Commtest Instruments vbBalancer Instrument Reference Manual

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Instrument Reference

Guide

Revision

May 19

2008

vbBalancer™ and vbBalancer+™

Imbalance Correction Instruments

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All rights reserved. No part of this document may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, mechanical, photocopy, recording or otherwise without the prior written permission of Commtest Instruments Ltd. For information, contact:

Commtest Instruments Ltd 28B Moorhouse Avenue Christchurch New Zealand E-mail [email protected]

Printed in New Zealand.

Disclaimer

The information contained in this document is subject to change without notice. Names and data used in examples are fictitious unless otherwise noted. This document is distributed as is, without warranty of any kind, either expressed or implied, respecting the information supplied, including but not limited to implied warranties for the document’s quality, performance, merchantability, or fitness for any particular purpose. Neither Commtest Instruments Ltd nor its employees, dealers, agents or distributors shall be liable to the user of this document or any other person or entity with respect to any liability, loss or damage caused or alleged to be caused directly or indirectly by this document.

Trademark Notice

vb™, vb1000v™, vb1000™, vb2000™, vb3000™, vb5™, vb6™, vb7™, vb8™, vbBalancer™, vbBalancer+™, 6Pack™, vbXManager™ and PROFLASH™ are trademarks of Commtest Instruments Ltd. vbSeries®, Commtest®, vbOnline® and Ascent® are registered trademarks of Commtest Instruments Ltd. Other trademarks and registered trademarks are the property of their respective owners.

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Contents

Section 1: Introduction.................................................1

Standard Features ................................................................. 1

Standard Kit Items ................................................................. 2

Instrument Capabilities........................................................... 3

Precautions............................................................................ 5

Hazardous Locations ............................................................. 7

Instrument Connections ......................................................... 9

Front Panel Buttons ............................................................. 10

LED Indicators ..................................................................... 11

Charging the Battery Pack ................................................... 12

Battery Features .................................................................. 12

Removing the Battery Pack.................................................. 13

Operating Overview ............................................................. 14

Balancing ...................................................................................14

Onsite Analysis ..........................................................................15

Section 2: Instrument Basics.....................................16

Powering On/Off .................................................................. 16

Navigating Menus ................................................................ 17

Returning to a Previous Menu.............................................. 17

Using Navigation Keys and Icons......................................... 18

Selecting an Option from a List ............................................ 19

Canceling an Option ............................................................ 21

Displaying Hint Labels and Detailed Help ............................ 21

Displaying Alternative Options ............................................. 22

Entering Alphanumeric Characters ...................................... 23

Entering Punctuation, Spaces and Special Characters ........ 25

Using Other Icons ................................................................ 26

Section 3: Using Sensors...........................................28

Supported Sensor Types ..................................................... 28

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Connecting Sensors to the Instrument ................................. 29

Mounting Sensors................................................................ 30

Setting up the Accelerometer............................................... 31

Permanent Mounting .................................................................32

Setting up the Tachometer................................................... 32

Tachometer Signal from a Keyphasor® ............................... 34

Section 4: Balancing Rotors ......................................35

Methods for Balancing Rotors.............................................. 35

The Balancing Process ........................................................ 36

Tips for Balancing ................................................................ 37

The Tachometer .................................................................. 37

Suggested Trial Weight Mass and Location ......................... 38

Manually Entering Balancing Information ............................. 38

Setting up a Balancing Job .................................................. 39

Balance Planes and Weight Positions....................................... 40

Balance Planes....................................................................40

Weight Position (Reference Mark) ......................................40

# Sensors...................................................................................41

CH Position..........................................................................42

Averages....................................................................................44

Machine Information ..................................................................44

Rotor Weight, Diameter and Speed ....................................44

Reference Mark ...................................................................44

Weight Orientation.....................................................................45

Tach Trigger ..............................................................................45

Weight Lin Dist ..........................................................................45

Store Units .................................................................................46

Combining Trim Weights...................................................... 46

Reviewing Previous Balancing Jobs..................................... 47

Section 5: Balancing Walk-through...........................49

Step 1. Set Up a New Balance Job ...................................... 49

Step 2. Take an Initial Reading ............................................ 50

Step 3. Take a Trial Reading ............................................... 51

Step 4. Balance the Rotor.................................................... 54

Step 5. Perform Trim Balancing ........................................... 55

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Step 6. Viewing and Saving Balancing Jobs ........................ 57

Section 6: Analyzing Measurements Onsite.............58

Tips for Taking Measurements............................................. 58

Walk-through: Taking Measurements................................... 59

Working with Charts............................................................. 62

Analyzing Measurements..................................................... 62

Using Cursors ............................................................................63

Zooming.....................................................................................65

Viewing Multiple Charts........................................................ 66

Changing Chart View........................................................... 66

Setting the Y Axis (Amplitude) Scale.................................... 67

Amplitude Display Units ....................................................... 68

Setting the RPM................................................................... 69

Viewing Orders .................................................................... 70

Viewing Revolutions............................................................. 71

Saving Measurements ......................................................... 71

Section 7: Setting Measurement Options .................73

Setting Measurement Units and Spectrum Scaling .............. 73

Setting Measurement Parameters........................................ 75

Creating Your Own Parameter Sets..................................... 76

Assigning Sensors to Channels ........................................... 77

Explaining Spectrum Parameters......................................... 78

Fmax..........................................................................................78

Spectral Lines ............................................................................79

Fmin...........................................................................................79

Tach Trigger ..............................................................................80

Averaging...................................................................................80

Average Overlap..................................................................80

Explaining Waveform Parameters........................................ 80

Equivalent Fmax........................................................................80

Number of Samples...................................................................80

Duration .....................................................................................81

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Section 8: Measurement Types and Their Uses.......82

Spectrum ............................................................................. 82

Waveform ............................................................................ 83

Tachometer Display............................................................. 83

Bump Test ........................................................................... 84

Coast-down/Run up ............................................................. 85

Taking Multi-channel Simultaneous Measurements ............. 86

Setting up Sensors and Channels............................................. 86

Saving Multi-channel Measurements ........................................87

Section 9: Taking Recordings ...................................89

Walk-through: Taking Recordings........................................ 89

Taking Individual and Multiple Recordings ........................... 90

Saving Recordings............................................................... 91

Reviewing Recordings ......................................................... 91

Deleting Recordings............................................................. 93

Attaching Notes ................................................................... 93

Section 10: Creating, Editing and Deleting Items ....94

Storage Capacity and Recording Volume ............................ 94

How are Recordings Organized and Stored?....................... 94

Working with Folders ........................................................... 96

Creating a Folder.......................................................................96

Renaming a Folder ....................................................................96

Deleting a Folder .......................................................................96

Restoring a Deleted or Over-Written Folder.............................. 96

Working with Machines ........................................................ 97

Creating Machine Structures .....................................................97

Creating Parameter Sets ...........................................................98

Adding Structures to Existing Machines.................................... 99

Copying Machine Structures ................................................... 100

Renaming Machine Structures ................................................100

Deleting Machine Structures ................................................... 101

Working with Sensors ........................................................ 101

Defining and Editing Sensors ..................................................101

Using the Bias Voltage Check .................................................103

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Deleting Sensors .....................................................................104

Working with Notes............................................................ 105

Creating Notes......................................................................... 105

Editing Notes ...........................................................................105

Attaching Notes .......................................................................105

Viewing Notes.......................................................................... 106

Removing Notes ......................................................................106

Deleting a Note Permanently...................................................106

Deleting all Recordings in a Folder .................................... 107

Deleting all Stored Information........................................... 107

Section 11: Utilities...................................................108

Setting the Date and Time ................................................. 108

Adjusting the Date Format.......................................................108

Selecting Your Local Timezone.......................................... 109

Adjusting Sound Volume.................................................... 109

Set the Instrument Language............................................. 109

Printing Directly to a Network Printer.................................. 110

Adjusting Screen Contrast ................................................. 111

Turning the Backlight On/Off.............................................. 111

Recharging the Instrument................................................. 112

Estimating Remaining Operating Time............................... 112

Conserving Battery Power ................................................. 112

Setting Backlight Timeout........................................................113

Setting Sleep Mode Timeout ...................................................113

Setting Complete Powerdown Timeout ...................................114

Checking How Much Memory is Available ......................... 114

Freeing Instrument Memory............................................... 114

Backing Up the Instrument Database................................. 115

Upgrading Instrument Firmware (Proflashing).................... 116

Section 12: Troubleshooting ...................................118

Contacting Technical Support ............................................ 118

Resetting an Unresponsive Instrument .............................. 118

Network Communications Problems .................................. 118

Ethernet Connection Lost in Windows Vista....................... 120

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Appendix: Specifications .........................................122

vbBalancer......................................................................... 122

vbBalancer+....................................................................... 124

Index ..........................................................................126

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Section 1: Introduction

Please keep this Instrument Reference Guide for future reference and read it before operating your balancing instrument.

Although this book makes use of common balancing and vibration analysis concepts, it is not intended as a comprehensive guide or training manual. Please ensure you have the relevant knowledge and experience to carry out the procedures described. It is essential to follow all appropriate safety precautions when working near rotating machinery.

Product and support feedback If you any have questions not answered by this reference guide, or would like to make a suggestion, please contact us at www.commtest.com.

Standard Features

• Balancing capability: single and dual plane

• Tachometer and Keyphasor® input for speed and phase

measurements

• DSP for fast, accurate calculations

• 24-bit A/D converter providing high-precision measurements

• Displacement, velocity and acceleration measurements

• Frequency and time domain measurements

• 1 GB non-volatile flash memory providing almost unlimited

recording storage

• Time and date stamped recordings

• vb firmware - upgradeable using Commtest PROFLASH

• Temperature compensated graphical LCD (Liquid Crystal

Display) with 480 x 320 pixels and white LED backlight

• 4500 mAh custom Lithium Ion battery pack

• Battery charger

• USB or Ethernet interface for PC communications

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Section 1: Introduction

Standard Kit Items

• vbBalancer portable imbalance correction instrument (vbBalancer or vbBalancer+) with carry strap and sensor bracket

• Power adapter 12 V 3 A output, center positive

• DC car adapter 12 V DC output

• USB data transfer cable

• Accelerometers (IEPE/ICP®-type)*

• Accelerometer coiled cables*

• Accelerometer magnetic mounting bases*

• Triple BNC adapter (vbBalancer+ model only)

• Non-contact laser tachometer sensor

• vbXManager software on CD-ROM

• Instrument Reference Guide

• Warranty card

• QA card

• Carry bag

* Number provided varies according to instrument model. vbBalancer: 2 units, vbBalancer+: 4 units.

Balancing kit items

• Reflective tape

• Adjustable tachometer stand with magnetic mount

• Tachometer extension cable (5 meters)

• Accelerometer extension cables (5 meters)+

Number provided varies according to instrument model.

vbBalancer: 2 units, vbBalancer+: 4 units.

Note: Thoroughly inspect your instrument kit's contents upon receipt. If any kit items are missing, please contact Commtest customer support or your sales agent for assistance.

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Section 1: Introduction

Instrument Capabilities

vbBalancer instrument capabilities vary according to model variant. For details of your specific instrument model's capabilities, see the information listed below.

Measurement Channels (Max)

vbBalancer vbBalancer+

Dual (2) Channel Simultaneous

Four (4) Channel Simultaneous

Balancing Capability

vbBalancer vbBalancer+

Balancing 2 Planes

Balancing 2 Sensors

Balancing 4 Sensors

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Section 1: Introduction

Measurement Capabilities

vbBalancer vbBalancer+

Spectrum/Waveform

Bump Test

Coast-down/Run-up

Sensor Output Accepted

vbBalancer vbBalancer+

Acceleration

Velocity

Displacement

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Section 1: Introduction

Precautions

Please read and understand this section before operating your instrument. Heed all warnings and recommendations to prevent data loss, data inaccuracy, damage to the instrument, or injury to yourself.

Do not attach sensors to any object with a high potential voltage i.e. a voltage that exceeds 50 V DC or 32 V AC or the ‘safety extra low voltage’ (SELV) defined by your local power authority.

Ensure the cables and bootstrap cannot become entangled with any rotating or moving machinery.

Do not bring any objects sensitive to magnetic fields near the magnetic mounting bases (e.g. cardiac pacemakers, credit cards, floppy disks, video tapes, audio cassette tapes, mechanical watches).

Do not operate the instrument in an explosive environment.

Do not detach the battery pack from the instrument for more than 10 minutes. This will cause the instrument's date/time to be lost. The instrument will retain all recordings and other information.

Neck-straps must be connected to the instrument via the 2.5 turn stainless steel rings provided. The strap must not be connected directly to the unit as this will defeat the 10 kg safety release provided by the rings. Replacement rings are available from Commtest.

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Section 1: Introduction

Use only an approved power adapter 12 V 3 A output, center positive. Do not use the plug-pack transformers supplied with previous Commtest instrument versions (such as the vb1000-3000 and Profiler) as these transformers will be damaged.

The cover over the comms and charger connectors provides an essential seal. It must be in place whenever using the instrument in an industrial environment.

Ensure that the drive current is turned on when using an IEPE/ICP®-type accelerometer, otherwise the measurements will be incorrect.

Mount the sensor properly before taking measurements to ensure their accuracy and consistency.

Use a mild detergent diluted in warm water to clean the instrument. Do not use abrasive or polishing substances, hydrocarbons, petrochemicals or solvents, as they will degrade the plastic casing.

Do not place the instrument or the magnetic mounting base anywhere that the temperature might exceed 140 °F (60 °C). This will degrade the battery pack and magnet.

If the instrument malfunctions, return it to an authorized dealer. Do not attempt to repair the instrument yourself as this will void your warranty.

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Section 1: Introduction

Hazardous Locations

Selected models of the vbBalancer range have been approved by the Canadian Standards Association (CSA) for use in hazardous locations meeting this classification: Class I, Division 2, Groups A, B, C, D.

Those models are clearly identified with the CSA logo and a Hazardous Location information panel. Models without those markings are NOT approved for operation in hazardous locations.

The Class I Div 2 classification is officially defined in the Canadian Electrical Code part 1, but can be summarized as:

A location in which volatile flammable gases or vapors are present but confined within closed systems from which they can escape only in case of accidental rupture or abnormal operation; or in which ignitable concentrations of gases are normally prevented by positive pressure or mechanical ventilation, and which might become hazardous through abnormal operation of the ventilation equipment.

The approval specifically covers use in the United States of America and also any other countries which recognize the CSA certification.

When using a certified vbBalancer in a hazardous location, the installation must comply with the vbX Installation Control Drawing for Hazardous Locations, including all its foot-notes and warnings. This drawing, number CIL2100VBX, is inserted on the following page.

The vbBalancer instrument will be supplied complete with appropriate sensors for use in Class I Div 2 environments. As indicated on the drawing, alternative sensors may be used, provided they are certified for use in these locations and their entity parameters meet the limits shown on the drawing.

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Section 1: Introduction

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Section 1: Introduction

Instrument Connections

The top panel of the instrument is equipped with the following connection interfaces.

1. Ethernet port. Connects to a standard 8P8C ('RJ45') male plug terminator

2. Charger power socket (12 Volt 3 Amp input). This may be used to power the instrument and/or to charge the instrument's battery pack

3. USB socket. Provides a data connection between the instrument and the vbXManager software's host computer

4. BNC sensor input (Channel 1)

5. BNC sensor input (Channel 2) OR LEMO seven-pin input* (Channels 2 to 4)

6. LEMO four-pin tachometer input

* This feature is only available on the vbBalancer+ instrument model

Note: The comms and charger area's protective rubber gasket should be kept closed and in place when collecting data in the field. Doing so will help maintain the environmental sealing of the instrument case.

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Section 1: Introduction

Front Panel Buttons

Instrument Front Panel

Turn the instrument On/Off.

Cancel/Go Back. A long press takes you back to the Main Menu.

Accept/Go forward to the next menu.

Activate alternate functions for each key. In some menus the keys can perform several functions; to see what options are available press ALT to toggle the key functions.

Help key: expand on-screen icons with easy to see hint labels. A long press displays detailed help text.

Navigate up/down through a list. To move more rapidly

through a list, press and hold.

Navigate left/right. Also expands and collapses levels in the navigator and directs movement between split-screen menus e.g. the Review Vibration Menu.

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Section 1: Introduction

LED Indicators

Five LED indicators located on the instrument's front panel indicate the instrument's current state and warn of measurement problems.

Instrument LEDs

Power supply (GREEN)

Illuminates when power is supplied to the

instrument from the power adapter.

Charging (RED)

Indicates that the instrument battery is

charging.

Danger (RED)

Illuminates when a DSP or critical error

occurs.

Alert (AMBER)

Not used on vbBalancer instruments models.

OK (GREEN)

Indicates that a measurement is being, or

has been, collected su

ccessfully (without an

error or alert triggered).

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Section 1: Introduction

Charging the Battery Pack

Warning: Before charging the battery pack, ensure that the power

transformer used is an approved power adapter 12 V 3 A output, center positive. Do not use the plug-pack transformers supplied with previous Commtest portable analyzers such as the vb1000-3000 or Profiler instruments.

The power adapter supplied in the kit provides the correct DC voltage.

• Connect the AC power adapter included with the instrument to a powered outlet (100-240 Volt, 50/60 Hz).

Note: The optional car adapter charging lead may also be used to charge the battery pack in a vehicle with a 12 V negative-chassis power system.

• Connect the adapter's DC output to the instrument's charger power socket. The instrument's Power supply and Charging LED indicators will illuminate indicating a charging state.

Notes: A full battery charge will complete in approximately 3 hours.

The fast-charge Lithium Ion-type battery pack should be charged for a minimum of 1 hour before or during its initial use.

Battery Features

The instrument is powered by a rechargeable custom Lithium Ion battery pack with a normal operating range of 6.5 V to 8.4 V.

The instrument is equipped with an internal backup component that protects data and settings in case the battery pack is momentarily removed from the instrument. The backup component is kept charged by the battery pack if the battery pack is functioning normally. The instrument has a number of inbuilt features which help ensure that the battery pack is always sufficiently charged.

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Section 1: Introduction

Below 7 Volts the instrument automatically turns off the backlight to prevent further power draining and displays a flashing battery icon as a reminder to recharge the battery.

At 6.5 Volts the instrument automatically powers down to conserve power.

With a battery charge of 25% or less the instrument will enter Complete Powerdown Mode when powered off.

Removing the Battery Pack

• Loosen the screws (2 x Phillips Head) attaching the battery cover to the bottom panel of the instrument.

• Set aside the battery cover and extract the battery.

Warning: Do not detach the battery pack from the instrument for more than 10 minutes as this will cause the date/time to be lost. However, all data will be retained.

Replacement batteries (part number BATT0206) are available from authorized Commtest Instruments distributors.

Warnings: Power should not be supplied to the instrument when removing the battery. Unplug any connected power adapters before proceeding.

Damaged batteries should not be re-inserted into the instrument. Dispose of damaged batteries responsibly.

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Section 1: Introduction

Operating Overview

You can use the instrument to perform the following tasks:

• Balance machines using single and dual plane methods

• Take live, free run measurements for onsite analysis of

vibration spectra and waveforms

Balancing

You can analyze and correct rotating mass imbalance problems in-situ. A rigid rotor can be balanced in one or two planes.

• Take an initial measurement of the imbalance.

• Attach a trial weight to the balancing plane and take another

measurement. For dual plane balancing, do the same for the second plane.

• Attach correction weights to the balancing planes as recommended by the instrument.

• Take a measurement in each plane to confirm that the rotor is balanced. Any residual imbalance can be removed via trim balancing.

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Section 1: Introduction

Onsite Analysis

You can measure vibration spectra and waveforms, and analyze these onsite. This is suitable for one-off investigations.

• Set measurement parameters on the instrument.

• Measure and analyze the spectrum or waveform.

• Record the data to memory (optional).

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Section 2: Instrument Basics

This section describes how to perform basic functions on your instrument.

You will learn to:

• Power up the instrument and turn it off

• Navigate menus and select options

• Enter and edit characters and punctuation

• Replace the on-screen icons with hint labels

• Display detailed help

Powering On/Off

• Press to power up the instrument or turn it off. The following menu displays at power up.

Main Menu

The Main Menu displays details such as the amount of charge remaining in the battery, today's date and time, the instrument serial number, firmware version, the instrument's user-defined description and the name of the currently selected folder.

• A long key press on

will always return you to the Main

Menu.

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Section 2: Instrument Basics

Note: Once powered up, and with a battery state above 25%,

pressing the button will place the instrument into Sleep Mode not Complete Powerdown Mode. If the battery state falls below 25% charge, the instrument will enter Complete Powerdown Mode immediately when turned off.

Navigating Menus

• To navigate menus, press the key that displays the name of the task you want to perform e.g. to begin balancing, from

the Main Menu press Balance.

Returning to a Previous Menu

• To return to a previous menu press If you have opened several sub-menus, pressing this key will return you to the original menu. A long press will return you to the Main Menu.

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Section 2: Instrument Basics

Using Navigation Keys and Icons

Use the keypad arrows and on-screen arrow icons to navigate backwards/forward through menus, move up/down and across lists, and expand/collapse structures containing other items. When you

are working with large numbers of machines, press to collapse the displayed machine structures. This will speed up navigation as you can move the selection bar from machine to machine, rather than having to scroll through each individual parameter set, location and point.

Move the selection bar in the direction indicated.

Move the selection bar to the top of a single column list. Move one column to the left in a multi-column list.

Move the selection bar to the bottom of a single column list. Move one column to the right in a multi-column list.

Expand the highlighted machine structure to show its points, locations and parameter sets. Move to the right-hand side of the screen in a split-screen menu.

Collapse the highlighted machine structure so that only the top level is visible. Move to the left-hand side of the screen in a split-screen menu.

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Section 2: Instrument Basics

Selecting an Option from a List

When there are a large number of choices available they will display in list format. On-screen arrows allow you to scroll up, down, or across a multi-column list by pressing the arrow keys.

• To select an option from a list use the arrows keys to move the selection bar until your option is highlighted, then press

to select that option.

Example:

• From the Main Menu press Measure Vibration.

• To select Tachometer Display press or repeatedly

to highlight this option.

• Press to select this option.

Jumping directly to the end of a list When there are a large number of options, left and right arrows will display on either side of the screen.

Example:

• From the Main Menu press Measure Vibration. (A long

key press on

will return you to the Main Menu if you

have another menu open.)

• Select Spectrum Waveform by pressing

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Section 2: Instrument Basics

• Press Spectrum Waveform. Left and right facing arrows will appear on the right-hand side of the screen indicating that you can 'jump' to either end of this list.

• To jump to the last entry in the list press Press to jump to the first list entry.

Scrolling through a multi-column list

Lengthy lists are displayed in multi-column format. You can jump across the columns as well as scrolling up/down.

Example:

• Press to return to the Spectrum Menu, then press Fmax Fmin.

• To move to the next column in a multi-column list press

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Section 2: Instrument Basics

Canceling an Option

• To cancel an option press This will normally return you to the previous menu. If you have opened several sub-menus, pressing this key will return you to the original menu. A long press will return you to the Main Menu.

Displaying Hint Labels and Detailed Help

Each on-screen icon can also display a hint label. Hint labels are turned off by default so that less screen space is used.

• To display hint labels press The hint labels will disappear when you press another key.

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Section 2: Instrument Basics

Example:

• From the Main Menu press Review Vibration. (A long

press on will return you to the Main Menu if you have another menu open.)

• Press to display the hint labels and press this key again to hide them.

Press and hold to display more detailed help information.

Example:

• From the Main Menu press and hold Detailed help text will be displayed.

• Press again to hide the detailed help text.

Displaying Alternative Options

Pressing a key causes the instrument to perform the task shown

beside that key. For example, in the following picture, pressing will cause the Y Axis of the on-screen chart to expand.

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Section 2: Instrument Basics

Chart menu before pressing

However, in many menus one key can perform two functions. When

this is the case a small icon will appear at the top of the screen

(see the arrow in the previous picture). Pressing the key causes a different set of options to appear. The following picture shows the same chart menu after pressing this key.

Chart menu after pressing

Entering Alphanumeric Characters

Names can be up to 50 characters long and contain a mix of upper case and lower case letters, spaces, numbers and punctuation. To enter letters and numbers use the instrument keys in the same manner as a 'multi-tap' type mobile phone, pressing the keys repeatedly to cycle through the characters until you reach the one

you want to use. For example, to enter the number 7 press four times. Pressing a different key causes the cursor to immediately go to the next space; if you need to use a character that is on the same key as the previous character, pause for a moment until the cursor moves forward so that you don't overwrite your text.

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Section 2: Instrument Basics

Example: To rename the currently selected folder to FANS:

• From the Main Menu press Folders.

• Press Edit Name.

• Press then Clear All to clear the current folder

name.

• Press three times until 'F' displays.

• To enter the letter 'a', press once.

• Press twice to display 'n'.

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Section 2: Instrument Basics

• Press four times to display 's'.

• To enter a space between words press . If you make a

mistake and wish to delete a character press

• Press then to display the advanced editing menu containing options for using upper and lower case characters etc.

• When you have finished entering your text press to save.

Entering Punctuation, Spaces and Special Characters

• To add punctuation, from the alphabetic character screen

press to display the punctuation menu.

• To use a punctuation character press the corresponding key. The instrument will then re-display alphabetic characters.

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Section 2: Instrument Basics

Spaces and special characters You can insert spaces between words, change from upper to lower case and delete or insert special characters as required. Pressing

to display hint labels will help you use the various editing

commands.

Example:

• From the Main Menu press Folders.

• Press Edit Name.

• Press to activate alternative functions then to

display the advanced editing menu containing options for lower case letters, deleting characters etc.

Using Other Icons

Each on-screen icon represents a function that you can use to perform a task, such as creating or deleting an item. To perform the task represented by the icon, press the key beside that icon.

Remember that you can press to display hint labels for each icon.

Use these icons to create your machines.

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Section 2: Instrument Basics

Use To do this

Create a new machine

Create a new point

Create a new location

Create a new parameter set

Use these icons to manage all your items.

Use To do this

Create a new item

Edit the selected item

Delete the selected item

Copy the selected item into memory

Paste the copied item to the highlighted position

Page 36

Section 3: Using Sensors

This section explains which sensors are compatible with your instrument and describes how to use them.

You will learn:

• What sensors may be used with your instrument

• How to use the supplied accelerometer and tachometer

• How to correctly mount a sensor

Supported Sensor Types

The following table summarizes the sensitivities and types of measurement that can be taken by each sensor supported on each instrument model.

vbBalancer

Sensor Type Sensitivity Measurement Types

Accelerometer

mV/g 0.1-10 000

Acceleration Velocity Displacement

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Section 3: Using Sensors

vbBalancer+

Sensor Type Sensitivity Measurement Types

Accelerometer

mV/g 0.1-10 000

Acceleration Velocity Displacement

Velocity Sensor

mV/in/s 0.1-10 000 mV/mm/s 0.34-90.55

Velocity Displacement

Displacement Sensor (or prox probe)

mV/mil 0.1-10 000 mV/µm 0.34-90.55

Displacement

For information on how to define a sensor see Defining and Editing Sensors (page 101).

Connecting Sensors to the Instrument

Sensors are connected to the instrument via BNC and, in the case of the vbBalancer+ instrument, seven-pin LEMO socket. Use the provided triple BNC adapter (LEMO breakout cable) to connect channels 2 through 4 if using these channels on a vbBalancer+ instrument.

BNC (left), seven-pin LEMO (right)

Note: The triple BNC adapter's three BNC inputs are numbered to indicate channel.

BNC Attach the sensor cable plug to the BNC connector(s) by inserting and gently turning clockwise. Remove by turning in an anti-clockwise direction then pulling up

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Section 3: Using Sensors

LEMO To attach a LEMO triple BNC adapter, line up the red dot on the LEMO connector with the red line on the instrument socket and insert. Remove by firmly gripping the connector and pulling away from the instrument without twisting.

Warning: Do not remove the LEMO connector by pulling the sensor cable. This may damage the cable. Always remove by gripping the end connector.

Sensor Inputs

Input vbBalancer vbBalancer+

BNC 1 (Channel 1)

BNC 2 (Channel 2)

LEMO 1 (Channels 2-4)

LEMO 2 (TACH)

Mounting Sensors

Your choice of sensor mounting will affect the accuracy of balance jobs and vibration measurements.

Accelerometers are usually mounted using the supplied magnetic base. However, for permanent installations on balancing stands, they can be stud mounted as described in Permanent Mounting (page

32). You can also apply these instructions to velocity sensors.

You should mount tachometers according to the manufacturer's instructions.

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Section 3: Using Sensors

Setting up the Accelerometer

Plug the accelerometer connector into an instrument BNC sensor input (or into a triple BNC adapter connected to the instrument if using a vbBalancer+ instrument). Now screw the accelerometer into the magnetic base and attach it to the measurement point using these guidelines:

• Attach the accelerometer to a sturdy, rigidly mounted and non-flexible structure, where vibration from the rotating part of the machine will be accurately transmitted. Do not attach sensors to sheet metal, guards, or any machine structure which is not closely coupled to the source of vibration in the spinning rotor, as the vibration of such a structure will be different to the vibration source.

• The attachment structure must be at least 10 times heavier than the accelerometer itself. Do not mount the accelerometer on lightweight motors or similar parts as the weight of the accelerometer will distort the vibration signal. Use a smaller accelerometer for small structures.

• Attach the accelerometer as closely as possible to, and in line with, the centerline of the bearings in order to avoid distorted signals.

• The mounting surface should be flat and smooth where the accelerometer makes contact. Attach the accelerometer using the supplied magnetic accelerometer base or a threaded stud on the machine surface. The accelerometer should not move independently of the machine part it is attached to.

• Ensure the accelerometer is oriented correctly as vibration can differ greatly with respect to direction.

• If you are undertaking an ongoing study of a particular measurement point, always attach the accelerometer at exactly the same position used for previous measurements (mark the position if necessary).

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Section 3: Using Sensors

• Keep the accelerometer clear from other cables, ensuring it is not twisted, kinked or tangled.

Permanent Mounting

To mount using the stud method, prepare a mounting spot on the machine following the specifications shown in the diagram below.

• Unscrew the magnetic base from the sensor and screw onto the threaded stud. We recommend you use a thread locking compound.

Stud Mounting Spot

Caution: Do not use a wrench to tighten the accelerometer as this may damage the sensor.

Setting up the Tachometer

A tachometer collects information on a machine's rotation speed, providing you with an exact reading of machine speed as a measurement is taken. This is more accurate than using a default RPM as a machine's speed can vary significantly under different loads.

The tachometer also provides information on the angle at which the rotor is vibrating. The angle is measured from a fixed reference mark on the rotor and is called the ‘phase angle’. To balance a rotor it is necessary to consider not just the amplitude of vibration but also the phase angle. The amplitude shows the severity of the imbalance and the phase angle indicates the geometry of the imbalance.

Warning: The laser tachometer is a class 2 laser product. Do not stare into the laser beam.

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Section 3: Using Sensors

Setting up the tachometer

• Locate the drill hole in the tachometer and screw this onto the end of the mounting base movable arm.

• Plug the cable socket into the tachometer connecting pins then turn the locking ring to make a secure connection.

• Locate the TACH input on the instrument and attach the other end of the cable to this.

• Stop the rotor.

• Cut out a small strip of the supplied reflective tape,

approximately 5 mm x 15 mm (0.2" x 0.5").

• Stick the reflective tape to a machine part that rotates at the rotor speed e.g. the shaft. This trigger spot should provide a pronounced increase in reflection as it passes under the tachometer light beam. The tape width must be at least double the diameter of the light beam spot.

• Mount the tachometer magnetic base to a stationary portion of the machine, convenient to the trigger spot.

• Position the tachometer slightly away from the centerline of the rotating machine part in order that it is not 'blinded' by reflections from the surface of the machine part. The sensor should be positioned within the measurement range shown in the following diagram.

• Start the rotor and wait till it is at normal running speed.

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Section 3: Using Sensors

• Now test if the tachometer will trigger. From the Main Menu

press Measure Vibration.

• Press Tach. The screen will display the rotor running speed in RPM and Hz. These values will continuously update but should stabilize, indicating that the tachometer is triggering reliably. If the RPM does not stabilize adjust the position of the tachometer.

Tachometer Signal from a Keyphasor®

If your machine has a proximity-probe based tachometer sensor (e.g. Keyphasor®), this can be used as the tach signal for your vbBalancer+ instrument. The sensor should have a buffered front-panel BNC output, to ensure the instrument's measurements can’t interfere with pre-existing speed measurements. Keyphasor LEMO connector tach cables can be purchased through your local Commtest reseller for this purpose.

The Keyphasor proximity sensor gap should be adjusted so the driver box output is -8 V +/- 2 V (i.e. -6 V to -10 V) when the sensor is over the shaft. This is the normal mid-range position for these sensors. When the sensor is over the keyway its output will be -14 V to -22 V, depending on its make and model.

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Section 4: Balancing Rotors

This section describes the procedure for performing balancing operations with your instrument.

You will learn to:

• Understand the balancing process

• Select appropriate balancing settings

• Set up a balancing job

• Manually enter balancing values

• Use the instrument's suggested balance weight calculations

Methods for Balancing Rotors

The instrument can balance rotors that are rigid and which do not flex significantly at their operating speeds.

An imbalanced rotor is one that has an uneven mass distribution that causes the rotor to vibrate when it is rotated. Balancing a rotor requires correcting the uneven mass distribution by adding or removing weight to/from precisely calculated positions on the rotor.

A rigid rotor can be balanced in one plane or two planes i.e. any uneven mass distribution in the rotor can be corrected by adding/removing weights to/from one or two selected cross-sectional planes on the rotor.

For single plane balancing the mid plane of the rotor is usually used as the balancing plane. For dual plane balancing, usually the planes at the extreme ends of the rotor are used; however, other planes on the rotor can be used also.

Since the effect of a rotating weight (i.e. the centrifugal force) increases with the radial distance of the weight, it is common to add weight to, or remove weight from, the rim of the rotor rather than a position close to the centre of rotation. Making weight adjustments at the largest possible radial distance minimizes the amount of weight that needs to be added to or removed from the rotor.

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Section 4: Balancing Rotors

The centrifugal force of a heavy spot on the rotor that causes the rotor to vibrate increases with the square of the rotational speed. The vibration level of the rotor may be acceptable at one speed but not at another. Therefore, it is important to always allow the rotor to settle to its normal operating speed before taking balancing analysis measurements.

Whether a rotor should be balanced in one plane or two planes depends on the dimensions and operating speed of the rotor. The following guideline is commonly used:

Rotor Length to Diameter Ratio

Operating Speed Balancing Technique

0.5 or less

1000 RPM or less Single plane balancing

More than 1000 RPM Dual plane balancing

More than 0.5

150 RPM or less Single plane balancing

More than 150 RPM Dual plane balancing

Note: Before attempting to balance a rotor you must confirm that the cause of vibration is uneven mass distribution in the rotor. Good balancing results can be obtained only if vibration is caused by uneven rotor mass distribution. Attempting to balance a rotor with other problems will not, in general, reduce the vibration level.

The Balancing Process

A rigid rotor can be balanced in one or two planes. The following steps are involved:

Setting Balancing Parameters - Select the units and balancing method.

Initial Reading - Measure the initial imbalance.

Trial Reading - Attach a trial weight to the balancing plane and take

another measurement. For dual plane balancing, the same is also done for the second plane.

Balancing - Attach correction weights to the balancing plane(s) as recommended by the instrument.

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Section 4: Balancing Rotors

Trim Balance - Take a measurement in each plane to confirm that the rotor is balanced. Any residual imbalance can be removed via additional trim balance cycles.

Tips for Balancing

• Before performing a balance job, clean the rotor removing any dirt or loose-hanging material such as rust, flaking paint etc, which may affect balancing results if they fall off later.

• Ensure that any weight(s) you add will not come loose at the normal rotor speed and that it will not obstruct machine motion. If possible, manually rotate the rotor to ensure that the weight does not clash with any part of the machine, keeping in mind that the rotor's center line may shift when operated at its normal speed.

• Ensure the weight of any mechanism used to hold the correction weights in place is included as part of the correction weight. If you are welding on the weight, make sure that the weight of the flux is not included (scrape the flux off before weighing the electrode).

• Ensure that the shape of the correction weight does not cause it to become a dirt trap since dirt accumulated on the weight may cause rotor imbalance.

• It is important to attach the correction weight(s) at the same radial distance that the trial weight was i.e. if the trial weight was attached 'n' mm/inches from the center of the rotor, the correction weight must also be attached 'n' mm/inches from the center of the rotor.

The Tachometer

The tachometer provides the instrument with information regarding the rotational speed of a rotor and the angle at which the rotor is vibrating. The angle is measured from a fixed reference mark on the rotor and is called the ‘phase angle’. To balance a rotor you must consider both the amplitude of vibration and also the phase angle. The amplitude shows the severity of the imbalance and the phase angle indicates the geometry of the imbalance (i.e. the location of the

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Section 4: Balancing Rotors

heavy spot). Setting up the Tachometer (page 32) contains information on how to set up the tachometer to measure phase angles.

Suggested Trial Weight Mass and Location

The instrument can assist with balancing operations by calculating an appropriate trial weight mass and location for you. Please refer to topics CH Position and Reference Mark, for help with calculating the trial weight location, and Machine Information, for help with calculating the trial weight mass.

Manually Entering Balancing Information

You have the option to manually enter amplitude and phase values for the initial, trial and trim readings. This allows you to:

 Interrupt the balancing process without saving the values,

then re-enter them later and continue balancing.

 Experiment with different trial weight masses and

placements to see the effect on the imbalance, without having to attach weights to the machine.

 Calculate the effect of further trim balances.

 Change the units used in a final balancing report by

selecting different units then re-entering the collected values.

• To enter a value manually, work through the balancing setup

process as normal then press to take a reading. The

icon will appear in the upper left-hand corner of the screen (for a dual plane balance the CH2 icon will also appear).

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Section 4: Balancing Rotors

• To enter your own values for CH1 press (press for

CH2 when using two channels, or and then select a channel when using three or more on a vbBalancer+).

• Press to enter an amplitude value and to enter

phase. Press twice to exit and return to the Initial, Trial or Trim Reading Menu and continue the balancing job.

Setting up a Balancing Job

The Balance Setup Menu gives you a large degree of flexibility in how you set up balancing jobs. Many of the setup items are optional; you can also select items in any order you wish e.g. you can select a machine to save the balancing report to at the beginning or end of the process, or perform balancing without saving the report.

• From the Main Menu press Balance.

• Press New Job. This clears any existing setup data

from previous balancing jobs.

• Press Setup and use the options in the Balance Setup Menu to apply your preferred balancing settings.

The rest of this section describes the Balance Setup Menu options. Balancing Walk-through on page 49 explains how to use these options when performing a balancing job.

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Section 4: Balancing Rotors

Balance Planes and Weight Positions

Use these options to set the type of balance job (single or dual plane) and specify a weight position reference system i.e. where on the rotor you will place the balance weights in relation to a reference mark.

Balance Planes

• From the Balance Setup Menu press then use the arrow keys to highlight the number of balance planes to use.

• Press to select. This will display the Balance Weight Setup Menu.

Weight Position (Reference Mark)

Performing balancing operations on a rotor requires you to establish a positioning system for balance weights. To do this you must first establish a reference mark somewhere on the rotor circumference then choose the weight positioning system that is most appropriate for your balance job.

Degrees Measure the angle in degrees (0° to 359°) from your reference mark. The radius of the rotor must stay constant.

Circumference arc Measure the linear distance around the outside of the rotor from the reference mark to the balance weights.

# Fixed positions Create a fixed number of attachment positions, e.g. drilled and tapped holes, that are equally spaced on a fixed radius from the center of rotation.

To assist with the physical balancing setup you can use a different weight position system for each balancing plane if desired.

• From the main menu screen press

Balance. Press

New Job to clear your setting or press Setup to use your existing configuration

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Section 4: Balancing Rotors

• Press Balance Planes then use the arrow keys to highlight the number of balance planes to use.

• Press to select. This will display the Balance Weight Setup Menu.

• From the Balance Weight Setup Menu press Plane A Weight Position then use the arrow keys to highlight your

choice and press to select.

• If you select circumference arc or # fixed positions this will open the Circumference or # Fixed Position sub-menus where you need to specify the rotor circumference or the number of fixed positions. Enter the required value then

press

Note: The circumference units used (inches or mm) are set in the

Balance Setup screen by pressing Weight Lin Dist then Linear Distance.

• If you have selected dual plane balancing press Plane B Weight Position and repeat the previous steps for Plane

• Press repeatedly if necessary to return to the Balance Setup Menu from where you will specify your sensor

settings. If you selected dual plane balancing, pressing will automatically take you to the Balance Sensor Setup Menu.

# Sensors

This option lets you specify the number and type of sensors you are using. This menu also contains an option that allows the instrument to recommend where to place trial weights (optional).

• If the Balance Sensor Setup Menu is not already displayed

press

# Sensors from the Balance Setup Menu then

select the number of sensors required and press

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Section 4: Balancing Rotors

• Press CH1 Sensor and select a sensor or Create New Sensor if a new one as required (refer to Defining and

Editing Sensors on page 101 for more information).

• Press to return to the Balance Sensor Setup Menu. To specify a 2nd, 3rd or 4th sensor for dual plane balancing

press to as required and repeat the previous step.

Note: The vbBalancer+ instrument allows full four-sensor simultaneous monitoring of both horizontal and vertical axes on each bearing. This ability provides confidence that a balance on any one axis has not worsened vibrations on the other. The vbBalancer instrument allows simultaneous two channel dual plane monitoring.

• If you want the instrument to help you determine where to place your trial weights use the CH Position option on the left-hand side of the screen (see next topic), otherwise skip

this step and press to return to the Balance Setup Menu.

CH Position

Note: This item is optional.

CH Position is used in conjunction with Reference Mark. The instrument uses this information to calculate where on the rotor you should place your trial weights after taking an initial reading. The aim is to reduce the initial vibration in order to maximize the accuracy of the trial weight readings. The instrument will recommend a trial weight angle based on the following:

• The phase of the initial reading

• The angle between the tachometer and sensor (the CH

Position)

• The angle between the tachometer reflective tape and the weight reference mark on the rotor (the Reference Mark)

You need to enter both the CH Position and the Reference Mark Location so that the instrument can calculate the trial weight angle. See Reference Mark (page 44) for further instructions.

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Section 4: Balancing Rotors

• If the Balance Sensor Setup Menu is not already displayed

press # Sensors from the Balance Setup Menu, select

the number of sensors to use then press .

• Press CH1 Position and enter the angle from the

tachometer to your sensor then press For dual plane balancing, repeat this step if you want the instrument to recommend trial weight placement angles for both planes.

After you take the initial reading the instrument will display the suggested trial weight angle in the upper right of the screen.

Notes: Angles are measured in the direction you designate as your Weight Orientation i.e. with rotation or against rotation.

If you are performing a dual plane balance you should only use this option in cases where each balance plane is physically close to its sensor, and the two planes are separated from each other by a distance greater than the rotor diameter. In particular for overhung rotors this option should only be used for single plane balancing on the closest bearing and balance plane, to help with reducing the static imbalance only. The CH2 or CH4 sensor and weight reference mark must be in line with those of CH1 or CH3.

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Section 4: Balancing Rotors

Averages

Averaging the 'out of balance' values can increase the accuracy of your measurements, allowing the instrument to make more precise recommendations for the size and placement of balance weights. A higher number of averages produces more accurate measurements, but lengthens the recording time accordingly.

Machine Information

Entering machine information is optional. It allows you to specify some of the physical properties of the machine being balanced.

Rotor Weight, Diameter and Speed

Entering the rotor's weight, diameter and speed helps the instrument to calculate the appropriate size and placement of trial weights based on your machine's physical properties. The aim is to calculate a trial weight which will cause a significant change from the initial reading.

• From the Balance Setup Menu press Machine Information and use the on-screen options to enter your

values. If you need to enter a decimal point press then

• If you need to change a measurement unit e.g. for rotor weight or diameter, return to the Balance Setup Menu and

press Weight Lin Dist. Change the units as required

then press

After you take the initial reading the instrument will display the suggested trial weight mass in the upper left of the screen.

Note: In Manual input mode and without a tachometer connected no suggested angle and weight will be provided by the instrument.

Reference Mark

Note: This item is optional.

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Section 4: Balancing Rotors

Reference Mark is used in conjunction with CH Position. The instrument uses this information to calculate where on the rotor you should place your trial weights after taking an initial reading.

You need to enter both the Reference Mark Location and the CH Position so that the instrument can calculate the trial weight angle. Refer to topic CH Position for more information.

• If the Balance Machine Menu is not already displayed press

Machine Information from the Balance Setup Menu.

• Press Reference Mark and enter the angle from the tachometer reflective tape to your reference mark then press

If these marks are aligned with each other enter zero.

After you take the initial reading the instrument will display the suggested trial weight angle in the upper right of the screen.

Weight Orientation

Weight Orientation allows you to choose where to place balance weights on a rotor, relative to the rotor's direction of rotation.

With rotation (WR) means you choose a reference point then place your weights forward of that point in the direction of rotation (i.e. in the same direction as the rotor turns).

Against rotation (AR) means that if the rotor is turning forward then you place your weights backwards from the reference point (i.e. in the opposite direction of the rotor’s rotation).

Ensure that with the rotor stationary you measure angles in the direction specified. Do not rotate the rotor in the direction specified.

Tach Trigger

Tach Trigger allows you to specify whether you are using a standard tachometer or a Keyphasor® if using a vbBalancer+ instrument.

Weight Lin Dist

Weight Lin Dist allows you to specify the measurement units for linear speed distance, balance weights and rotor weight.

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Section 4: Balancing Rotors

• To change the displayed units press Weight Lin Dist

then press to cycle through the linear speed options or

to open the Weight Units Menu where you can set

balance and rotor weight units.

• When you have set your units press to navigate back to the Balance Setup Menu.

Store Units

Store Units allows you to specify your preferred measurement units and overall scaling for balancing jobs.

Combining Trim Weights

As you continue to fine-tune a balance job, you may end up with several trim weights fixed at various angles on the balancing planes. You can combine all trim weights for an individual plane into one weight/angle solution using the Adjust Weights calculator.

• After taking a trim reading press to display the Trim

Weight Menu (or from the Balancing Menu Balance Readings).

• Press the left-hand arrow key beside Plane A (or Plane B)

then press Adjust Weights. The Adjust Weights Menu displays the locations and amounts of your individual trim weights, the weight vector (Existing Total), and the target weight and angle (the trim weight/angle solution you hope to achieve).

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Section 4: Balancing Rotors

• Use the left-hand arrow keys to highlight one of the trim

weights you want to remove then press Remove or Keep. The calculator will re-calculate the suggested weight/angle accordingly. You can experiment with different remove/keep combinations by repeating this process (to add

a subtracted weight back to the calculator press again).

• When you are satisfied with the suggested weight calculation

press to continue. To exit the menu without combining any trim weights, replace any removed weights before continuing.

Reviewing Previous Balancing Jobs

• From the Main Menu press Balance then Select Machine.

• Use the left-hand arrow keys to highlight a machine. All balancing jobs associated with that machine will display in the right-hand Recordings column.

• Press the right-hand arrow key select the Recordings column; a black border will appear around it indicating that you can now browse through the recordings.

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Section 4: Balancing Rotors

• The newest balance job is highlighted at the top of the

column. Press to display the selected recording or use the left-hand up/down arrow keys to select another.

• In the Balancing Menu press View and Save to see the Balancing Report.

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Section 5: Balancing Walk-through

This walk-through guides you through the process of balancing a rotor using single and dual plane balancing. Dual plane balancing requires additional steps; these extra steps are indicated with this

symbol

You will learn to:

• Take initial imbalance measurements

• Set up and apply trial weights

• Balance the rotor using correction weights

• Perform trim balancing to further reduce the vibration

• Save and review your balancing job

• Produce balancing reports

Step 1. Set Up a New Balance Job

• From the Main Menu press Balance then press New Job to clear any previous settings.

• Press Setup. Use the options in the Balance Setup Menu to choose the required settings for your balancing job.

The following screen shows the settings that were selected for this walk-through.

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Section 5: Balancing Walk-through

Step 2. Take an Initial Reading

• Stop the machine.

• Attach the sensor to the bearing housing closest to the rotor.

For best results attach it in the radial direction in which the machine is most flexible (and vibrates the most).

Attach a sensor to each of the bearings supporting the rotor. It is not important how the sensors are paired or which sensor is attached to which end.

• Set up the tachometer (see Setting up the Tachometer on page 32).

• Start the machine and let the rotor settle to its normal operating speed. Since the vibration level depends on the speed of the rotor it is important to take all readings while the rotor is operating at its normal speed.

• From the Balance Setup Menu press to take the initial reading. The initial reading measures the 'out of balance' level of the rotor.

After a few seconds, the instrument displays the speed of the rotor in RPM and Hz, the vibration level due to the imbalance (i.e. amplitude at 1X the rotor speed), and the phase angle of the vibration. Note that our measurement shows an

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Section 5: Balancing Walk-through

amplitude of 3.59 mil. The aim is to reduce this to an acceptable level.

For dual plane balancing two sets of values will display.

• Wait for the readings to stabilize then press

Step 3. Take a Trial Reading

• Stop the machine.

• Establish a reference mark on the balancing plane. This will

be used to measure the angular position of the trial weight and the final balance weights. The reference mark can be at any position around the balancing plane. It does not need to be referenced to the tachometer reflective tape position.

In dual plane balancing, establish a reference mark on Plane B also. It does not need to correspond with the Plane A reference mark.

• Attach a trial weight to the balancing plane. It is important that the trial weight is not too large, as this may damage machine bearings, and not too small as its effect will be imperceptible. Your trial weight must be of sufficient mass to change the imbalance by approximately 30% in amplitude or 30% in phase (these figures are the industry norm). This will allow the instrument to perform its calculations accurately.

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Section 5: Balancing Walk-through

• The trial weight position should be near the rim of the rotor but can be at any angular position. Starting at the reference mark, measure the angular position in the direction you specified for the Weight Orientation. This will be either WR (with rotation) or AR (against rotation).

• In the Trial Weight Menu press and enter the value for your trial weight. If you need to enter a decimal point press

then

• Press to return to the Trial Weight Menu then press and enter the position of your trial weight in relation to the reference mark.

• Press to return to the Trial Weight Menu. Press to specify whether you are adding or removing (drilling out) weight.

• Replace safety covers, start the machine again, and let the rotor settle to its normal operating speed.

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Section 5: Balancing Walk-through

• Press to take a reading of the imbalance with the trial weight added. After a few seconds, the instrument displays the speed of the rotor in RPM and Hz, the vibration level with the trial weight added.

• Wait for the readings to stabilize then press If the trial weight was not of sufficient mass to affect the imbalance the instrument will display a warning prompt. You can redo the trial reading several times if required or continue with balancing.

• The instrument then displays the prompt 'Will the Trial Weight be removed now?' Press the appropriate key. You can redo the trial reading several times if required or continue with balancing. Here we have added trial weights twice more to obtain a new trial reading.

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Section 5: Balancing Walk-through

Perform the same procedure for Plane B (attach a trial weight, enter its position and specify whether weight is being added or drilled out). If you are removing trial weights the Plane A trial weight must be removed before performing the Plane B trial reading.

Step 4. Balance the Rotor

With Initial and Trial Readings completed the Balance Weight Menu will now display. The instrument displays the weight required to correct the initial imbalance and the angular position at which it must be attached.

• Stop the machine. If you are removing trial weights as you go, do this now before attaching your correction weight.

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Section 5: Balancing Walk-through

• Attach or remove the recommended correction weight as indicated by the instrument then proceed to Trim Balance.

For dual plane balancing two sets of values will display.

Step 5. Perform Trim Balancing

• Replace safety covers, start the machine again and let the rotor settle to its normal operating speed.

• Press to take a trim reading. After a few seconds the instrument displays the vibration level with the imbalance corrected.

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Section 5: Balancing Walk-through

• Press to accept this measurement. The instrument will now display the details of additional weight adjustments required to trim balance the rotor (i.e. to further reduce the level of vibration/imbalance). You can end balancing at this point or continue with another reposition of trim balance weights, as indicated, to improve on the balance level. Repeat trim balancing until you are satisfied with the results.

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Section 5: Balancing Walk-through

Step 6. Viewing and Saving Balancing Jobs

• This step is optional. To view the Balancing Report Menu

press The screen displays the results of your initial and trial readings, the balance reading and any trim balances.

Saving the balance job

• From the Balancing Report Menu press Save Balance Job. Select or create a machine to save this balancing job to

then press To print the report directly from the

instrument press Print Report (see Printing Balance Reports Directly from the Instrument (page 110) for setup details).

Note: You can save multiple balance jobs to a single machine to create a 'history' of balancing.

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Section 6: Analyzing Measurements Onsite

This section describes how to take measurements and perform onsite analysis.

You will learn to:

• Take a measurement

• Change how a measurement is displayed

• Perform analysis using cursors and zooming

• Set a measurement's RPM

• Store a measurement

Tips for Taking Measurements

• You should always take measurements using the machine operating mode that is typical for that machine (using a typical load and running speed). This will ensure that the loads on the components, such as bearings, are the same as those that define their wear. For multi-operating mode machines it is best to take measurements when the loads on the bearings are at a maximum and to take all future measurements in the same mode.

• When taking the measurement, try not to lean on the machine and do not put heavy objects (e.g. heavy tool boxes) on it since this will change the vibratory behavior of the machine.

• If there are machines operating nearby that might affect the vibration of the machine you are measuring, stop those surrounding machines if possible.

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Section 6: Analyzing Measurements Onsite

• In addition to the measurements that you will be taking, if possible, stop and listen to the sound of the machine; look for loose bolts and oil leaks; take note of any machine parts that are vibrating visibly; feel for hot bearings and manually ‘feel’ the vibration (e.g. with a screwdriver) to look for symptoms that might later aid vibration analysis. This should be done only if it is safe to do so.

• If you have a stroboscope (not included in the instrument kit) you may wish to use it to ‘freeze’ rotating shafts, belts, couplings etc to observe their operating shapes and relative speeds in order to look for symptoms that might later aid vibration analysis.

Walk-through: Taking Measurements

Onsite analysis involves watching a machine's vibration on-screen as it occurs, and analyzing the measurement on the instrument. This method of measuring allows you to take a quick look at a machine's vibration patterns without storing the measurement. (You can choose to save the measurement at any time by creating a machine to save it to, or by selecting an existing machine definition stored in the instrument.)

• Attach the sensor (and tachometer if you are taking rotor speed and phase angle measurements). Now start the machine and allow it to operate under its normal load and running speed.

• From the Main Menu press Measure Vibration.

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Section 6: Analyzing Measurements Onsite

• Select your measurement type by using the arrow keys to

move the selection bar then press or by pressing the quick access buttons to the right of the screen.

• The measurement default settings are displayed on-screen. You can change any of these defaults before taking a measurement. See sub-heading 'Changing the default settings' at the end of this topic.

• To start the measurement press The instrument and sensor will take a short time to settle before measuring begins. Measurements are taken in 'free run' mode, which means that the signal continually updates on-screen until you stop the measurement.

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Section 6: Analyzing Measurements Onsite

• To stop the measurement press You can now analyze the measurement on-screen, including displaying the amplitude of spectral peaks and identifying harmonics (see Analyzing Measurements).

• To stop viewing the measurement and exit without saving

press

• To save the measurement press and select an existing machine location or create a new one (see Saving Measurements on page 71).

Changing the default settings

• To change any of the settings shown on the right of the screen, press the keys beside the on-screen icons.

• To change any of the settings shown at the bottom of the

screen press then press the keys beside the on-screen icons. Pressing keys causes the display to cycle through the available options or opens a sub-menu where you can enter a value or choose a value from a list.

Pressing lets you change the measurement setup

• If a sub-menu opens, make your changes then press This will apply your settings and return you to the previous menu where you can change further settings if required.

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Section 6: Analyzing Measurements Onsite

• To select a different sensor press then press Sensor Setup. Press the Change Sensor key opposite your chosen measuring channel then use the left-hand arrow keys

to highlight a sensor and to select it. Press the left-hand arrow key beside your chosen channel to enable it then

press twice to begin measuring.

Working with Charts

You can display a separate on-screen chart for each measurement channel. This allows you to watch multiple 'live' measurements at the same time, freeze all measurements on-screen and compare them together, and also toggle between the charts so that you can view them one at a time.

Viewing two waveforms simultaneously

Analyzing Measurements

• To halt a measurement so that you can analyze it press The overall vibration value will display at the top right of the screen.

• Press to display hint labels for analysis options such as zooming and displaying cursors.

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Section 6: Analyzing Measurements Onsite

Pressing displays analysis options

Using Cursors

Cursors are a valuable tool for analyzing your data. You can use them to show the amplitude and frequency of a peak, identify harmonics, and show the frequency difference between two peaks.

Placing a cursor on the chart

• Press or repeatedly to activate a cursor and move it across the screen. To move the cursor rapidly from peak to peak within a displayed waveform recording press and hold the key.

Placing a second cursor on the chart

• Press Second Cursor. The second cursor will not be immediately visible as it will be placed directly behind the first cursor (the new cursor's values will appear at the top right of the screen).

• Press or repeatedly to move the cursor to either side so that it becomes visible.

Toggling the active cursor

• Press

Second Cursor to toggle between the two

cursors.

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Clearing cursors

• Press then Clear Cursors to remove all cursors and harmonics.

Displaying the amplitude/frequency of a peak

• Press or repeatedly to activate a cursor and move it across the screen. The frequency and amplitude values indicated by the cursor will display at the top right of the screen.

Displaying the frequency or time difference between peaks

• Press or repeatedly to activate a cursor and move it to the first peak.

• Press Second Cursor to add a new cursor to the

display and press or repeatedly to move it to the second peak.

Both cursors' values appear at the top right of the screen. The delta symbol will appear on the far right of the

screen. The value beside the delta displays the frequency or time difference between the two peaks.

The delta indicates the frequency/amplitude difference of two peaks

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Displaying harmonics

• Press then press Harmonics Sidebands. Press

or repeatedly to move the cursor over different

peaks.

Additional cursors will display at frequency or time values that are whole-number multiples of the frequency or time value indicated by the main cursor.

Turning harmonics off

• Press then press Clear Cursors to remove all harmonics and sidebands.

Zooming

Zooming allows you to take a closer look at a specific area of interest on a chart.

Chart zoom and expansion options

• Magnifying glass icons on the left of the screen indicate that zooming options are available. (If the magnifying glass icons

are not visible press toggle them on.) Press to display hint labels for zooming and expansion options.

Zooming horizontally (across the chart)

• To expand the peaks of a spectrum or waveform use the right-hand arrow keys to move the cursor to the position of

interest and press X Axis Zoom repeatedly to zoom in on the cursor position by a factor of two per key press. The more spectral lines or waveform sample points used, the more times you can zoom.

Zooming vertically and horizontally

• To see low amplitude peaks more clearly move the cursor to

the position of interest and press Y Axis Zoom to zoom in by a factor of two per key press.

• Press

X Axis Zoom to expand the frequencies on either

side of the cursor.

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Zooming out

• Press X Axis Expand repeatedly to zoom out

horizontally and to zoom out vertically.

Viewing Multiple Charts

When you measure more than one channel simultaneously, or display both a spectrum and waveform, each chart will display on-screen. You can view the measurements on all charts at the same time (waveform or spectra only when viewing three of more measurements simultaneously) or select a specific chart to work with. When using analysis options such as zooming, these will only be applied to the selected chart.

Selecting a chart

• With the charts displayed press (You don't have to display the hint labels but this will help.)

• Press Select Chart. The axes of the selected chart will become thicker and darker to indicate that this chart has the

focus. Press repeatedly to toggle which chart you wish to work with.

Displaying a single chart

• To make one chart fill the entire screen select the chart as

described in the previous instructions then press Chart Zoom.

• To re-display all charts press again.

Changing Chart View

You can toggle between waveform and spectrum recordings, and set the default layout of multi-channel and single-channel onscreen measurements using the Change View and Multi Chart Layout functions.

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Note: The following functions are only available when viewing multi-channel (two or more) and multi-domain (spectrum+waveform) measurements.

Selecting a chart layout

• With the charts displayed press to display hint labels.

• Press Change View to alter the currently displayed

chart type. Press repeatedly to toggle between waveform or spectrum displays for up to four channels, and spectrum+waveform to view both measurement types onscreen simultaneously for individual channels.

Changing how multi-chart layouts are displayed

• With the charts displayed press to display hint labels.

• Press then press Chart Data Change to open the

Multi Chart Layout screen.

• Press to choose which channels will be displayed in your Multi Chart Layout.

• Press or to pick a layout from those listed. For single channel displays you may choose waveform, spectrum or spectrum+waveform. For multi-domain measurements using three or more channels and with all channels set to display simultaneously ('Show All Channels' in the previous step), you may only select waveform or spectrum for simultaneous display, not both.

Setting the Y Axis (Amplitude) Scale

Toggling the left axis scale between Linear, Log and dB will increase or decrease the amplitude of displayed peaks allowing you to see either the bigger picture or a more detailed view of the data. The Linear scale is suitable for most cases. Log scaling (base 10) is more useful for displaying vibration with both very large and very small amplitudes.

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• With the spectrum measurement displayed on-screen (either

still measuring or stopped) and highlighted press then

Y Axis Log to set the Y axis (amplitude) scaling options.

• Press Linear Log dB repeatedly to toggle between Linear, Log, and dB scaling (vdB and adB scaling are only available when measuring velocity and acceleration respectively).

• Press Y Axis Max. This is the highest amplitude value that will be displayed on-screen. Use the arrow keys to

highlight a value then press to select.

• Press Y Axis Range repeatedly to toggle the Y Axis range. This selects the lowest amplitude value that will be displayed on-screen relative to your chosen Max Value.

• When you have finished press to return to the measurement screen.

Fixed Y Axis scale options Setting a Max dB Value sets the highest value that the amplitude axis can display, so if a peak goes above this value while you are measuring you will not see the top of the peak. When using Linear scaling you have two extra display options.

Automatic: This allows the instrument to auto-scale the left axis to accommodate the highest and lowest peaks.

Current: This fixes the Y axis to whatever amplitude is currently displaying, regardless of how large or small the peaks become.

Amplitude Display Units

Your chosen Store Units (acceleration, velocity etc) determine which amplitude scaling options are available. The vdB scale is only available if you are taking velocity measurements and adB is only available if you are taking acceleration measurements. Linear and Log scaling are available for all measurement types. Choose from the following amplitude display units:

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Store Units Max dB Value

Linear Scale

Max dB Value

Log Scale

Acceleration

m/s2, mm/s2 m/s2, mm/s2

Velocity

mm/s, µm/s mm/s, µm/s

Displacement

mil, mm, µm mm, µm

Store Units Y Axis Fixed

Linear Scale

Y Axis Fixed

Log Scale

Acceleration

automatic, current, mm/s2 m/s2, mm/s2

Velocity

automatic, current, µm/s mm/s, µm/s

Displacement

automatic, current, m mm, µm

vdB The vibration velocity level vdB is defined as 20 times the logarithmic of the ratio of the RMS velocity level to a reference velocity value (the vdB reference). The value 1e-6 mm/s is an abbreviation for 1x10-6 mm/s and is the SI reference level. The value 1e-5 mm/s is the reference level used by the US Navy and many American industries.

adB The vibration acceleration level adB (US) is defined as 20 times the logarithm of the ratio of the RMS acceleration level to 1 µg RMS.

The SI version of adB is less commonly used, and has a reference value of 1 µm/s2.

Setting the RPM

Setting the 1X RPM allows you to view the chart in orders (for spectra) or revs (for waveforms). You can enter the RPM manually (if you know it), or set the RPM from a spectral 1X peak.

Entering the RPM manually

• With a measurement displayed press

then Set

RPM.

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• Enter a value using the number keys then press

Entering the RPM using the 1X peak

• Press or to move the cursor to the 1X peak.

• Press then Set RPM. The frequency of your

selected peak will be displayed.

• Press to save this frequency as the RPM value.

Note:

If a tachometer is connected to the instrument, the instrument will use the RPM from this rather than any entered value.

Viewing Orders

When orders are displayed, the frequency axis of a spectral chart is labeled in orders of running speed instead of in Hz or CPM. This allows you to see how closely spectral peaks correspond to the running speed of the machine. In addition, you can move a cursor to a peak of interest - the exact number of orders at that frequency will appear at the top-right of the screen.

• With a spectral chart displayed, set the RPM as described in

the previous topic and press

then X Axis Orders.

• To de-activate orders repeat the previous step.

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Viewing Revolutions

When Revs are displayed, the time axis of a waveform chart is labeled in revolutions of running speed instead of your regular measurement units.

• With the waveform chart displayed, set the RPM as described previously. The bottom axis will update to display revs.

Waveform chart displaying Revs on the X axis

Saving Measurements

• Stop the measurement by pressing then press

Save. You now need to select a machine, point and location to save the measurement to or create these now.

Selecting an existing machine

• Press Save to.. (keys to depending on the number

of channels used for the measurement), then press or

to scroll up and down and press Expand Navigator

repeatedly to expand out a machine so that its points and

locations become visible. Press to save the recording to your chosen location.

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Creating a new machine

• Press Save to.. (keys to depending on the number

of channels used for the measurement), then press Create New Machine. The following image shows the

machine creation icons after pressing to display hint labels

Creating a new machine to save the measurement to

• Enter a name for this machine then press

• Repeat this process to create a point then press

and use the arrow keys to select a location. Press until you see the message 'Data Saved'.

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Section 7: Setting Measurement Options

This section describes the different parameters used to take measurements and how to apply them.

You will learn:

• What the various parameters are for spectra, waveforms and other measurement types

• How to create parameter sets for taking measurements

• What measurement units and overall scaling options are

available

• How to assign sensors to channels

Setting Measurement Units and Spectrum Scaling

You can choose the standard US or SI units, or choose your own preferences. The table below summarizes the options.

• To set a preference, from the Main Menu press

Options then press Measuring Units.

• Press repeatedly to toggle which unit set is displayed. To set your own preferences select Custom then press the keys beside the first option you wish to change.

• Most on-screen options will open a sub-menu; press the keys repeatedly to cycle through the various options. When

you have finished press to save and return to the Measurement Units Menu.

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Units Spectrum

Scaling

Time Waveform Scaling

Accel

g, m/s2 RMS, 0-

pk,

pk-pk

RMS, 0-pk, pk-pk

Veloc

mm/s, in/s As above As above

Disp

mm, µm, mil As above As above

Unit Set SI US Custom

Frequency

Hz CPM Hz, CPM

vdB Units

vdB SI (1e-6 mm/s) vdB US (1e-5 mm/s) vdB US, vdB SI

adB Units

adB SI (1 µm/s2) adB US (1 µg) adB US, adB SI

Linear Speed Distance

mm in mm, in

Weight

g, kg lb, oz

lb, oz, tons, kg,

Balancing Units

Quantity Acceleration Velocity Displacement

Units

g in/s, mm/s mm, µm, mil

Scaling

RMS, 0-pk, pk-pk

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Setting Measurement Parameters

When you select a measurement type e.g. Spectrum Waveform from the Measure Menu the default parameters display on-screen.

Spectrum measurement setup showing default parameters

Example:

• From the Main Menu press Measure Vibration then

press Spectrum Waveform.

• Press to display hint labels then press Create New Paramset.

• The default parameters for a spectrum measurement are displayed. To change a parameter value press the key beside the value's on-screen label. This will cause the parameter to cycle through the available options, or it will open a sub-menu where you enter a value via the keypad or select a value from a list. If you have opened a sub-menu

save your changes by pressing

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Spectral lines sub-menu

Creating Your Own Parameter Sets

To create a new parameter set that you can store and reuse, do the following:

1. Open the menu for the measurement type you want to create

(from the Main Menu press Measure Vibration then use the arrow keys to select the required measurement type

and press to select it).

2. Press to display hint labels then press Create New Paramset to create a new copy of the default parameter set.

3. Press Edit Name and enter a description for this

parameter set then press

4. The new parameter set will be highlighted to indicate that it is selected. Press the keys beside the on-screen labels to set your values as described in the previous topic.

Example: Creating a custom spectrum parameter set

• From the Main Menu press Measure Vibration then

press

Spectrum Waveform.

• Press Create New Paramset.

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Section 7: Setting Measurement Options

• Press Edit Name and enter a name for this parameter

set then press

• Change Store Units to Acceleration. Press and select

the Accel then press .

• Set the Fmax to 1500 CPM. Press Fmax Fmin then

press to set the RPM to 10 x the machine running speed.

• Set the number of Spectral Lines to 800. Press Spectrum Waveform and use the arrow keys to highlight

'800 lines 2048 samples' then press

• Set the Average Overlap to 62.5%. Press to display

Averaging and Window options and press Average Overlap repeatedly to cycle through the values, then press

• Your new parameter set is now ready to use. If you have already defined a sensor and enabled a channel you can

now take a measurement by pressing Assigning sensors to channels is explained in the next topic.

Assigning Sensors to Channels

You must specify which sensor is assigned to each channel. When you take a measurement the instrument will know which sensor is being used and will offer you the appropriate measurement unit and overall scaling options for on-screen display. If you unplug a sensor in order to take a different type of measurement e.g. swapping an accelerometer for a current sensor, you will need to assign this new sensor to the channel.

• From the Main Menu press

Options.

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• Press Sensor Setup then press Change Sensor opposite your chosen measuring channel. (If this is new sensor that has not yet been defined in the instrument you will need to create a sensor definition before you can assign it to a channel. See Defining and Editing Sensors on page

101.)

• Use the arrow keys to highlight a sensor then press to assign it to your channel.

• To enable the channel for measuring, press the left-hand key beside your chosen channel. The text will change from --- to 'Enabled' to indicate that this channel can now be used to take measurements.

• Press twice to return to the Main Menu.

Multi-channel measurements To take simultaneous measurements, follow the procedure described previously and enable as many channels as required.

Explaining Spectrum Parameters

Fmax

The Fmax is the maximum frequency displayed on the spectrum i.e. the frequency range, starting from zero, over which vibration amplitudes are displayed.

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Section 7: Setting Measurement Options

In general, the higher the operating speed of the machine, the higher the Fmax needs to be to capture all crucial information. For vibration involving fingered elements such as gear teeth, fan blades, pump vanes, and bearing elements, an Fmax equal to 3 times the number of fingers multiplied by the operating speed is usually sufficient. For vibration not involving fingered elements, an Fmax equal to 40 times the operating speed is usually sufficient.

You can specify the Fmax of a measurement either as an exact value or as a multiple (order) of a machine's running speed.

• Select your measurement type then press Fmax Fmin. The options labeled 40 X and 10 X represent orders of running speed. The option ? X allows you to enter your own number of orders.

• Press one of the orders keys and enter your machine's default RPM value.

• Press twice to return to the measurement setup.

When you take the measurement the resulting display will use an Fmax with the specified number of orders (the value will be rounded up to the closest Fmax if an exact match is not available).

Spectral Lines

The resolution of the spectrum increases with the number of spectral lines used i.e. the more spectral lines the more information the spectrum contains. However, the more spectral lines used, the longer the measurement takes. Use many spectral lines only when required e.g. when you need to distinguish between two closely-spaced vibration frequencies or when the Fmax is very large. For coast-down or run-up measurements we recommend a resolution of 400 lines.

Fmin

The purpose of the Fmin setting is to eliminate the 'ski-slope' effect from the low frequency end of the spectra. All spectral lines below the Fmin value will be set to zero and will not be included in the overall RMS calculation.

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Section 7: Setting Measurement Options

Tach Trigger

When you select Tach Trigger, measuring begins only when a tachometer pulse is detected. If Tach Trigger is set to OFF the instrument will begin measuring as soon as the settling time has elapsed.

Averaging

When measuring vibration, several spectra are usually measured and averaged to produce an average vibration chart. The averaging process minimizes the effect of random variations or noise spikes that are inherent in vibration signals. Averaging is applied to amplitude values, not to the frequency range.

Average Overlap

Overlapping is a means of collecting and displaying data more quickly. As vibration measurements are collected a percentage of the new data is combined (overlapped) with each subsequent measurement. The higher the overlap percentage, the less newly acquired data is needed to generate a spectrum, and thus the faster the spectrum can be displayed. An overlap percentage of 50% is ideal for most cases.

Explaining Waveform Parameters

Equivalent Fmax

This allows you to control the waveform sampling rate by expressing it in terms of the maximum frequency of interest. For example, if you want a waveform with frequency content (Equivalent Fmax) up to 1 kHz, the instrument will automatically sample at 2.56 kHz. Changing the Eq. Fmax directly affects the sampling rate, so it has an inverse effect on the duration of the waveform.

Number of Samples

The resolution of the waveform increases with the number of samples used i.e. the more samples, the more information the waveform contains. However, the more samples in a waveform, the more memory is used up to store the waveform.

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Tip: An easy way to select the number of samples and duration is to let the instrument set them for you. Set the Equivalent Fmax so that it covers your required frequency range; the instrument will select the maximum number of samples and duration that can be used with this Fmax. You can then adjust these values as required.

Duration

The Duration of a waveform is its recording time. The duration value depends on the number of samples selected; increasing the number of samples increases the duration.

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Section 8: Measurement Types and Their Uses

This section describes how to setup and take different measurements types.

You will learn:

• How to take different types of measurements

• The uses of different measurement types

Spectrum

A vibration spectrum is a chart of vibration amplitude versus vibration frequency. The vibration spectrum of a machine component shows the frequencies at which the component is vibrating and the amplitude of vibration at each of these frequencies.

Spectra consist of discrete spectral lines displayed at fixed frequency intervals. The height of each spectral line represents the amplitude of vibration at that frequency. The more spectral lines in a spectrum, the higher the resolution of the spectrum (but more memory is used).

A simplified illustration of a discrete vibration spectrum

The key parameters you need to set are the number of spectral lines and the Fmax to ensure that all crucial information is captured.

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Section 8: Measurement Types and Their Uses

• From the Main Menu press Measure Vibration then

press Spectrum Waveform.

• Use the left-hand arrow keys to select a parameter set or

create a new one by pressing and setting the parameters as required.

• Press to begin measuring.

Waveform

Waveforms show how vibration levels change with time. A vibration waveform chart represents a series of equally spaced discrete sample points connected by straight lines. The chart shows the vibration level (amplitude) at each time interval during the measurement period. The more sample points in a spectrum the higher the resolution of the waveform (but the more memory used).

The key parameters you need to set are the duration and number of samples.

The duration determines the equivalent Fmax value.

• From the Main Menu press Measure Vibration then

press Spectrum Waveform.

• Use the left-hand arrow keys to select a parameter set or

create a new one by pressing and setting the parameters as required.

• Press to begin measuring.

Tachometer Display

Tachometer Display shows an updating readout of the machine speed.

• Connect the tachometer that will be used to measure the RPM.

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Section 8: Measurement Types and Their Uses

• From the Main Menu press Measure Vibration then

press Tach.

• Select the Standard tachometer or Keyphasor® sensor by

pressing Tach Type. This option is only available if using a vbBalancer+ instrument.

Bump Test

Note: This feature is not available on the vbBalancer instrument

model.

The bump test is a useful vibration analysis technique to help identify resonance frequencies in a machine's structure. It requires ‘bumping’ (i.e. hitting) the machine structure when the machine is stopped, while taking a peak hold measurement. Careful selection of the mallet or hammer is required along with the strength and direction of the bump to ensure that suitable frequencies are injected into the structure without causing damage.

• From the Main Menu press Measure Vibration then

press Bump.

• Use the left-hand arrow keys to select a parameter set or

press to create a new one and set the parameters as required.

• Press to begin sampling and 'bump' the machine with a hammer. Repeat several times.

Bump test measurements are taken in free run mode and use peak hold averaging. The instrument will take continuous samples and update the peak value for each spectral line whenever a line exceeds its previous value.

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Section 8: Measurement Types and Their Uses

Coast-down/Run up

Note: This feature is not available on the vbBalancer instrument

model.

Coast-down and run-up measuring involves taking a series of recordings with a short delay between them. This technique can be used to study the resonance behavior of a machine as its speed gradually increases during power-up, or decreases during coast-down.

• From the Main Menu press Measure Vibration then

press Coast Down/Up.

• Use the left-hand arrow keys to select a parameter set or

press to create a new one and set the parameters as required.

• Press and select the machine location to save

measurements to, then press again to begin measuring. After the first spectrum has been recorded switch off the machine, or begin ramping its speed up or down.

• Once the machine has stopped rotating, or its speed has

been fully adjusted, press to stop measuring and return to the Coast-down/Run-up Menu.

The measurement location will contain a large number of measurements.

Recommendations We recommend using a tachometer to obtain the RPM reading for each measurement as this aids interpretation.

You can set the Recording Interval as either a time interval between recordings, or as a change in machine RPM. We suggest using the latter, with the RPM Difference set to machine speed / 20. This will result in approximately 20 recordings being taken during a complete coast-down or run-up.

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Section 8: Measurement Types and Their Uses

A large number of recordings are taken during a coast-down or run-up. If you intend to repeat the process several times on a machine we recommend you save each set of recordings to a separate location so that they can be easily distinguished.

Taking Multi-channel Simultaneous Measurements

Taking a multi-channel measurement uses the same process as taking a single channel measurement. The only difference is that you must enable more than one channel, and save each measurement separately. You do not have to save each channel's measurements as you can selectively choose which ones to keep, e.g. you can save a measurement taken on channel 2 but discard the measurement taken on channel 1.

Setting up Sensors and Channels

• Select your measurement type and parameters as normal

and press then Sensor Setup.

• You will need to assign and enable a sensor to each channel you are measuring. Press Change Sensor opposite your chosen measuring channel. (If this is new sensor that has not yet been defined in the instrument you will need to create a sensor definition before you can assign it to a channel. See Defining and Editing Sensors on page 101.)

• Use the arrow keys to highlight a sensor then press to assign it to your channel.

• To enable the channel for measuring, press the left-hand key beside your chosen channel. The text will change from '---' to 'Enabled' to indicate that this channel can now be used to take measurements.

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• Repeat this process to enable additional channels then press

twice to begin measuring. To save the measurements

refer to the next topic.

Saving Multi-channel Measurements

1. When you are ready to stop measuring press

2. Press Save. This opens the Select Location to Save Menu.

3. You can save each channel's measurements or select only those that you wish to keep. Press the right-hand Save to.. key opposite the channel you wish to save.

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4. Use the arrow keys to select a location to save the

measurement or press if you need to create a new location. (See Storing Measurements on page 71 for more information.)

5. Press to return to the Select Locations Menu. Repeat this process from step 3 to store your other measurement(s). If you change your mind after saving a measurement press the channel's right-hand Save key again - the text will change to '(Don't Save)'.

6. When you have selected all the measurements you want to

save press The instrument will display 'Data Saved' before returning to the measurement screen.

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Section 9: Taking Recordings

This section describes how to take recordings with your instrument.

You will learn to:

• Take recordings

• Review and delete recordings

• Attach notes to recordings

Walk-through: Taking Recordings

The following instructions assume that you have already created your machine structures and have assigned parameter sets to the measurement locations.

1. Connect your sensors to the appropriate measurement locations. If you are taking tachometer readings, set up the tachometer also.

2. Ensure the folder containing the machines you want to monitor is selected; the name of the currently selected folder will display on the Main Menu beside the 'Folders' label. If

you need to select a different folder press Folders and

use the arrow keys to highlight your choice then press This loads the folder and all its machines into current memory and returns you to the Main Menu.

3. Press Review Vibration to display the machines within

this folder. If necessary, select Save by pressing (for a recording this should normally be set to Auto Save + Warn. Refer to Recording Save Options on page 91 for more information).

4. Use the left-hand arrow keys to scroll up and down and

press Expand Navigator repeatedly to expand out a machine so that its points and locations become visible.

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Section 9: Taking Recordings

5. To take an individual recording, highlight the parameter set that you wish to record. If you want to record all parameter sets at a location, highlight the location. The recordings will be taken one after the other in the sequence that they appear in the instrument.

6. To start the first recording press The instrument and sensor will take a short time to settle before recording begins.

When the recordings are finished the instrument stores them to the correct measurement location and returns you to the Record Review Menu. To take additional recordings, select another parameter set (or select a location to record all parameter sets under that location) and repeat this process from step 5.

Taking Individual and Multiple Recordings

You can choose to record all parameter sets at a location or select the parameter sets individually. This allows you to selectively record data, or speed up data collection by reducing the number of key presses needed to take multiple recordings at a single location.

• To record an individual parameter set, highlight it and press

to begin recording.

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Section 9: Taking Recordings

• To record every parameter set under a location, highlight the

location and press to begin recording.

Saving Recordings

When you are in the Record Review Menu you have several options for saving your recordings.

Auto Save

The instrument momentarily displays the recorded information on-screen before returning you to the Record Review Menu.

Record/Review

The instrument pauses after each recording so that you can review it on-screen.

• To take the next recording press This will either return you to the Record Review Menu or, if you have selected a location with multiple parameter sets underneath it, begin taking the next recording.

Free Run, Manual Save

The instrument will continuously record the signal and update the on-screen display.

• To stop measuring press To save the recording press

• To record the next parameter set without saving this

recording press This will either return you to the Record Review Menu or, if you have selected a location with multiple parameter sets underneath it, begin taking the next recording.

Reviewing Recordings

To review recordings immediately after taking them you can set the instrument's save option to Record/Review; to do this, from the Main

Menu press

Review Vibration then press repeatedly until

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Section 9: Taking Recordings

Record/Review + Warn displays in the lower right-hand corner of the screen.

To review stored recordings

1. From the Main Menu press Review Vibration.

2. To select a recording for review, use the left-hand arrow

keys to scroll up and down and press Expand Navigator repeatedly to expand out a machine so that its locations and parameter sets become visible.

3. When you highlight a parameter set its associated recordings will appear in the Review column. The newest recording is highlighted at the top of the column. To display

the newest recording press Review Selected Recording.

4. To display older recordings press once more to select the Review column; a black border will appear around the column indicating that you can now move up/down through the recordings. Use the left-hand arrow keys to select a

recording then press to display your selection.

Note: An asterisk beside a recording indicates that more than one recording type is contained within the record (spectrum and waveform).

The black border indicates all recordings can be reviewed