ALL-TEST PRO AT31 User Manual

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ALL-TEST Pro, LLC

ALL-TEST PRO® 31

Table of Contents

I. Introduction ..................................................................................................... 5

II. Safety ............................................................................................................. 6

Instrument Warnings and Considerations ......................................................... 6

General Safety Considerations ......................................................................... 6

III. ALL-TEST PRO® 31 Kit Components ....................................................... 7

Instrument Operation ....................................................................................... 7

Input Section ................................................................................................ 7

Display Section ............................................................................................ 8

Indicator Light Section ................................................................................. 8

Display Screen ............................................................................................. 8

Keypad Section ............................................................................................ 9

Instrument Test Leads ................................................................................ 10

IV. Testing a Three Phase Induction Squirrel Cage Motor.......................... 11

Operating Procedure 3-Phase Motors ............................................................. 11

Winding Test ................................................................................................. 11

Turn the Instrument On .............................................................................. 12

Select the Motor Test ................................................................................. 12

Observe/Record the Test Data .................................................................... 12

ERROR CODES ........................................................................................ 13

Continue with Other Phases ....................................................................... 14

Continue with Last Phase ........................................................................... 15

Phase Balance Test ........................................................................................ 17

Insulation Resistance Testing ......................................................................... 20

Rotor Test ...................................................................................................... 22

Bar Test ..................................................................................................... 22

Wave Form Test ......................................................................................... 23

Changing the Motor Test Frequency .............................................................. 24

V. Additional Functions and Features ........................................................... 26

Electro-Magnetic Interference (EMI): ............................................................ 26

Resetting the Unit .......................................................................................... 27

VI. Charging Your ALL-TEST PRO® 31 ....................................................... 28

VII. Data Interpretation Three Phase Motors ................................................ 29

Data Interpretation Tables .............................................................................. 29

Additional Data Interpretation Considerations Three Phase Motors ............ 30

Test Location ............................................................................................. 30

Rotor Windings .......................................................................................... 30

Confirming Suspected Winding Shorts ....................................................... 30

Method 1: Rotor Compensation .................................................................. 31

Method 2: Variable Frequency Test ............................................................ 31

VIII. DC Motor Testing .................................................................................... 32

Testing an Assembled DC Motor ............................................................... 33

Series DC motor ......................................................................................... 33

Compound or Shunt DC motor ................................................................... 33

Testing Shunt Field .................................................................................... 33

Armature Testing ....................................................................................... 33

DC Motor Analysis ........................................................................................ 34

IX. Additional Test Methods ........................................................................... 35

Wound Rotor Motors ..................................................................................... 35

Wye-Delta Motors ......................................................................................... 35

Capacitor Testing ........................................................................................... 36

X. Tech Support and Information ................................................................... 37

XI. Available Accessories for the ALL-TEST PRO® 31............................... 37

XII. Training Class ........................................................................................... 37

ALL-TEST PRO® 31 User Manual

I. Introduction

The light-weight, hand-held instrument can be used for immediate detection of winding shorts, insulation to ground faults, cable faults and more on AC/DC electric motors, transformers, coils, machine tool equipment, linear motors and much more. Testing can be performed at the motor connection box, the disconnect, or motor control center hundreds of feet away.

The ALL-TEST PRO® 31 (AT31) is designed to provide a simple test method for:

· troubleshooting faults

· commissioning new and rebuilt machines

· verifying quality assurance in electric motors and other wound equipment.

The patented tests performed for early winding fault detection:

· winding impedance test

· phase angle

· I/F current frequency response tests

· EMI (Electro-Magnetic Interference) test for detection of low-level EMI currents that can

affect readings and may be the result of other faults within the motor circuit

Note: The ALL-TEST PRO® 31 provides real time measurements of the on-going test. When combined with the ALL-TEST IV PRO™ provides the most comprehensive off-line motor analysis

system available at any price.

Insulation Resistance to ground: To prevent electrical shocks and to assure safety of personnel the AT31 provides an insulation to ground test. The insulation resistance test provides either 500 or 1,000 VDC, to measure the insulation resistance up to 500 Meg-Ohm.

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II. Safety

CAUTION: The AT31 is designed to test de-energized equipment safely and quickly. Improper application of the AT31 on live circuits is a danger to the user and will result in the destruction of the testing circuit, requiring instrument replacement.

Instrument Warnings and Considerations

The ALL-TEST PRO® 31 is a CE registered instrument. The following is a list of considerations for equipment life and accurate data collection:

Ensure that all power has been removed from the circuit being tested, including static power

stored in capacitors – Discharge all capacitors being tested.

Attaching the AT31 to live voltage will destroy the unit and void the warranty.

Do not attempt to change the batteries. Contact your distributor of the AT31, ALL-TEST Pro. LLC

at 860-399-4222 or via email, support@alltestpro.com, to have the battery pack replaced.

Do not open the instrument. Electrostatic charges may damage surface mount electronics. Please

contact your vendor or ALL-TEST Pro authorized repair center.

Use only the supplied charger for charging the instrument. It is an integral part of the charging

circuit. Using the wrong charger will damage your instrument.

General Safety Considerations

Following are general safety considerations for using the AT31 motor tester:

The AT31 is an off-line motor tester. All power and residual power must be disconnected. It

provides a safe method of testing your electric motors.

Follow all safety rules of your company and OSHA (or country equivalent) for off-line testing

methods, including appropriate Personal Protective Equipment (PPE). Improper or unsafe operation of

the equipment is the sole responsibility of the user.

For MCA testing, the AT31 sends out a low voltage, high frequency signal not harmful to the technician or most electronic equipment (variable frequency drives and soft starts). However, electronic equipment and personnel must observe appropriate safety considerations (disconnect electronic equipment) when performing the insulation to Ground resistance test (Meg-Ohm) test.

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III. ALL-TEST PRO® 31 Kit Components

Figure 1: AT 31 Kit

The AT31 Kit contains all of the necessary components necessary to test most electrical machinery:

A. ALL-TEST PRO® 31 instrument B. Batteries (installed) C. Test leads and clips D. Charger (115 or 230 Volt) E. Manual on CD Rom F. Carrying Pouch G. Reset Key (Only sent with units before Serial number 2029)

Instrument Operation

The instrument is divided up into three working areas:

1. Input Section

2. Display Area

3. Keypad

Input Section

The input section provides all the external connections to the ALL-TEST PRO® 31

A. Test lead port B. Charger port C. Ground test lead port for Insulation to Ground

Measurements

D. Reset Button (Serial number 2029 and higher)

A B

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Display Section

The display section is divided into 2 sections:

1. Indicator Lights

2. Display Screen

The Indicator Lights (section 1) informs the operator when an operation or test is being performed. The Display screen (section 2) allows the operator to select tests to be performed by the AT31.

Indicator Light Section

1. Charging light – Indicates that the unit is charging, light is illuminated red while charging, light

is green when fully charged.

2. Test indicator light – Light is illuminated green when the unit is testing

3. Insulation Test indicator light – The light illuminates yellow when the instrument is testing

insulation resistance. Caution – Applied voltage is 500 or 1,000 Volts DC.

Display Screen

The display screen has individual icons to select and perform the various motor and winding tests.

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1. Z/ψ Icon performs the Impedance (Z), Phase Angle (ψ), Current/Frequency (I/F) and Phase

Balance tests (used to identify developing winding faults).

2. ROT Icon performs the Rotor test (used to find squirrel cage induction motor rotor faults).

3. INS Icon performs the Insulation to ground resistance test (used to verify that the insulation to

ground resistance is sufficient to prevent electrical shock).

4. Battery charge level indicator. A fully charged battery will have 7 bars (it is recommended to

keep the AT31 on charge when not in use to ensure proper operation).

5. PWR OFF Icon turns the instrument off (the AT31 will automatically shut-off after about 5

minutes).

6. EMI Icon tests for EMI signals within the Motor System that could cause errors in the AT31 test

results.

Keypad Section

The keypad section provides keys to operate and control the functions of the AT31.

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1. Up direction and MODE key returns the AT31 display screen to the main menu.

2. F1/ON and Left direction key turns the AT31 on and moves the curser across the display screen

toward the left.

3. ZERO /OK (Selection) key selects which test to perform and provides reference selection to

calculate % difference of the measured impedance value.

4. Down direction and TEST key toggles between display screens and performs selected tests.

5. Right direction and F2/Hz key allows the operator to change the test frequency for the winding

test and moves the cursor across the display screen to the right.

Instrument Test Leads

The ALL-TEST PRO® 31 uses a 15 pin DB connector for winding testing. The red test lead is the output and the black test lead, is the return. For insulation testing, the yellow test lead should be connected to ground.

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IV. Testing a Three Phase Induction Squirrel Cage Motor

Testing can be performed remotely from the motor control center, the motor disconnect or at the motor itself. This instruction is provided to demonstrate all of the features of the ALL-TEST PRO® 31, which can also be used to evaluate other types of electric machines.

Note: The M2000 demo motor is used in this manual for procedural purposes only, it is not designed to simulate faults or test other features of the ALL-TEST PRO® 31

Materials for Testing with the ALL-TEST PRO® 31Figure 2: Equipment and Materials

To perform a motor test with the ALL-TEST PRO® 31 requires:

· ALL-TEST PRO® 31

· Test leads and lead clips

· A pen and paper (or a copy of the Motor Test Form on page 38).

Testing can be performed directly at the motor, at the nearest motor control center or disconnect. For

purposes of this manual, we will test at the motor using an M2000 training motor, this is for procedure only (the M2000 is not designed to simulate faults with the AT31).

Operating Procedure 3-Phase Motors

Winding Test

Measures and displays the winding impedance (Z), Phase Angle (ψ), Current Frequency response (I/F) and Impedance phase balance.

1. Label the three motor leads T1, T2, T3.

Note: It is very important to take the data in the same order

for long term trending.

2. Connect the Test leads to the Motor leads T1 & T2.

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Note: For quick trouble shooting the order of the readings is not important. However, for long term trending of the data, testing should be performed in the same order each time.

Optional: Connect the Yellow lead to ground, this is only required for measuring insulation to ground.

Turn the Instrument On

Press and hold the F1/ON key for 1 to 3 seconds. This will bring up the main display screen.

Select the Motor Test

1. Using the ◄ F1 and ► F2, keys highlight the Winding Test icon

2. Press the ZERO/OK Key to select the Winding Test icon (Z/ψ) from the main menu.

Observe/Record the Test Data

1. The default value is 200 Hz, as displayed in the bottom right corner of the display screen. a. The value of the impedance should be between 1 and 999 Ω. If the Z is less than 1 or

greater than 999 Ω change the test frequency of the winding test (see Changing the Motor Test Frequency on page 24).

b. The current frequency response value (I/F) must be between -15 and -50, if it is not

change the frequency of the winding test.

c. If the phase angle (Fi) is less than 15°, change the winding test frequency.

Note: If any of the measurements fall outside the above ranges, the test is not valid.

2. Display screen 2 displays the results of the current frequency test. To view display screen 2

Press the TEST key.

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ALL

TEST

31 Motor Test

Display screen 1: Displays the measured impedance in ohms 107, phase angle in degrees 66°, and the

frequency of the winding test, 200 Hz. The screen number (1) is displayed in the upper left hand corner.

Display Screen 1

Display Screen 2: Displays the results of the Current Frequency (I/F) response test (-45), (the current at

400 Hz is 45% lower than the current at 200 Hz). The doubled test frequency is displayed in the lower right hand corner; screen number (2) is displayed in the upper left hand corner. Note: The 16% shown in upper right corner is the change in phase angle when the test frequency is doubled. Not used for analysis purposes.

Display Screen 2

1. To return to the Display Screen 1 Press the TEST key again, this displays the impedance and

phase angle measurement.

2. Record the measured values on the Motor Test Form.

Motor ID: Location: Test Date: Test Frequency

Impedance (Z) Phase Angle (°) Z-Test or I/F

Pro®

Form

Phase 1-2

107

-45

Phase 1-3

Phase 2-3

If the impedance readings are out of range an error code will be displayed on the measurement screen.

· E1 error code means the impedance value is greater than 1000 ohms.

· E2 error code means the impedance value is greater than 10,000 ohms.

ERROR CODES

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Continue with Other Phases

1. Move the test leads to T1 & T3 to make the measurements on the next phase.

2. Read the Impedance (Z) and Phase Angle (ψ) values from display screen 1 for winding. Do not

fill in the phase balance until all three phases have been measured.

3. Depress the TEST key to display the Current Frequency Response (I/F).

Winding 2 Current

Frequency Response

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4. Record these test results on the Motor Test Form.

Motor ID: Location: Test Date: Test Frequency

Impedance (Z) Phase Angle (°) Z-Test or I/F Phase balance (opt)

Ins Resistance

Was rotor set to lowest value during phase balance test? Y__ N__

Rotor test performed? Y___ N___

Comments:

ALL-TEST Pro® 31 Motor Test Form

Phase 1-2

107 107

66 66

-45 -45

Phase 1-3

Test Voltage

Phase 2-3

Continue with Last Phase

1. Move the Test Leads to T2 & T3

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2. Read the Impedance (Z) and Phase Angle (ψ) values from display screen 1 for winding. Do

not fill in the phase balance until all three phases have been measured.

3. Press the TEST key to display the Current Frequency Response (I/F).

Winding 3 Current Frequency

4. Record these test results on the Motor Test Form.

Motor ID: Test Motor Location: Warehouse Test Date: 8/8/06 Test Frequency 200 Hz

Impedance (Z) Phase Angle (°) Z-Test or I/F Phase balance (opt)

Ins Resistance

Was rotor set to lowest value during phase balance test? Y__ N__

Rotor test performed? Y___ N___

Comments:

ALL-TEST Pro 31 Motor Test Form

Phase 1-2

107 107 109

-45 -45 -45

Phase 1-3

66 66 66

Test Voltage

Phase 2-3

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Phase Balance Test

This calculates the impedance unbalance between phases. This value can be used to relate energy, reliability and production-cost avoidance potential to electric motor systems impedance unbalance. The Impedance Unbalance Calculator (IUC) is available from ALL-TEST Pro. The concept of the IUC comes from Keeping the Spark in Your Electrical System: An Industrial Electrical Distribution Maintenance Guidebook published by the US Department of Energy, Bonneville Power Administration, Pacific Gas & Electric, PacifiCorp and Tacoma Public Utilities. As impedance varies with each phase, the current in each leg of the motor varies. This generates increased losses in the form of heat. Heat reduces both insulation life and the life of the lubricant. (The Impedance Unbalance Calculator is available from ALL-TEST Pro).

1. Place the Test leads on any 2 motor leads, for discussion purposes use T1 & T3.

2. Press the ZERO key to set the reference phase to zero. This establishes (T1-T3) as the reference

phase.

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3. Turn the motor shaft until the highest impedance value is obtained.

4. Press the ZERO key again. This sets the reference phase (T1-T3) to “0”. Enter 0 on the Motor

Test Form

5. Move the Test leads to T2 & T3. This determines the Impedance Phase Balance or Unbalance

Referenced to (T1-T3).

6. Turn the shaft slowly until the lowest percentage value is obtained. (The percentage should be

less than 3% of phase unbalance. A percentage > 5% indicates a fault in the winding and

should be investigated further).

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7. Record this value on the Motor Test Form for Phase 2-3. In this case the value is “0”.

8. Move the test leads to T1 & T2, this checks the Impedance Balance/Unbalance of Phase of the

final phase winding T1-T2 to T1-T3.

9. Turn the shaft slowly until the lowest percentage value is

obtained.

10. Record this value on the Motor Test Form for Phase 1-2. In this case the value is “2” which is

acceptable. Refer to the “Data Interpretation” Section of this manual for Acceptance criteria.

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Motor Voltage Rating

Insulation Test Voltage

1000

Volts AC

500 V

100

0 to 2500 Volts AC

1000 V

2501 to 5000 Volts AC

1000

– 2500 V

Application

Pass/Fail

Value

Insulation systems prior to 197

0 > 1 Meg

-Ohm + 1 Meg

Ohm per kV rating of motor

Random Wound motors less than 600 V

> 5 Meg

Ohms

DC Armatures and Form Wound motors over 600 V

> 100 Meg

Ohms

Insulation Resistance Testing

To prevent electrical shocks and to assure safety of personnel the AT31 provides an insulation to ground test. The insulation resistance test provides either 500 or 1,000 VDC, to measure the insulation resistance up to 500 Meg-Ohm.

NOTE: The following tables provide the recommended voltages and Minimum Insulation Resistance to

Ground values. If these values differ from your equipment manufacturers, follow their guidelines.

Insulation Resistance Test Voltage

Insulation Resistance Values (IEEE 43-2000)

1. Using the ON key or the MODE key from the keypad section to navigate to the display screen

(This is the main menu).

2. Use the ◄►to highlight the INS icon from the display screen. This

sets the ALL-TEST PRO® 31 up to measure insulation resistance to

ground.

3. Connect both the Red lead & the Yellow lead to ground.

4. Press the ZERO/OK key to select the Insulation Resistance Test. This displays screen 8, the

insulation resistance test screen.

5. View the insulation test voltage selected (upper right hand corner of the insulation resistance

display screen). Refer to the insulation resistance test voltage table above for the correct voltage.

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6. Press the F2 key to toggle between 500 & 1000V.

7. Press the TEST key and hold until the display shows ‘0’ MΩ. This is to verify the test leads are

connected to a good ground.

8. Move the “Red” test lead to any motor lead. Standard Insulation Resistance measurements

instruments require testing all 3 leads. This is not necessary with the ALL-TEST PRO 31 if impedance readings were successfully made on all three phases.

9. Depress the TEST key and hold until 500 MΩ is displayed. If the ALL-

TEST PRO 31 does not display 500 MΩ after one minute of testing, stop and record the value and test voltage on the Motor Test Form.

10. Depress the MODE key to return to the Main Display Screen.

ALL-TEST PRO 31 Motor Test Form

Motor ID: Test Motor Location: Warehouse

Test Date: 8/8/06 Test Frequency 200 Hz

Impedance (Z) Phase Angle (°) Z-Test or I/F Phase balance (opt)

Ins Resistance

Was rotor set to lowest value during phase balance test? Y__ N__

Rotor test performed? Y___ N___

Comments:

Phase 1-2

107 107 109

-45 -45 -45

>500

Phase 1-3

66 66 66

2 0 0

Test Voltage

Phase 2-3

500

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Rotor Test

Squirrel Cage Induction motors operate on the magnetic inductance principle. The rotor bars provide the path for the current to flow on the rotor. The current flow through the rotor bars creates a magnetic field which in turn causes the rotor iron to become a very strong electro-magnet. If rotor bars are open, broken or have large casting voids, current will not flow properly through the rotor bars. This causes unbalanced magnetic forces applied between the rotor and the stator, low operating torque and could eventually created physical contact between the rotor and the stator.

The ALL-TEST PRO® 31 provides a feature that performs 2 unique quick rotor tests to determine if any rotor issues are present in an assembled induction rotor. Rotor issues such as broken or loose rotor bars, casting voids in the cast aluminum rotors, eccentrically machined rotors and high resistance connections are some of the rotor issues easily recognized by the ALL-TEST PRO® 31.

Bar Test: Provides a visual “real time” indication of the response of the rotor to the energized stator field.

Waveform Test: Provides an additional visual indication of the change in response of the rotor to the energized stator field in the shape of a time wave form.

Both rotor tests send a low voltage AC sine wave signal through the stator winding and manual rotation of the shaft induces a voltage into the rotor bars.

The ALL-TEST PRO® 31 measures and displays the interaction between these 2 magnetic fields. A rotor without issues should provide a symmetrical and repeatable display. Induction rotors with issues will provide erratic, distorted displays. Additional tests are recommended to assist in determining the exact cause of the rotor issue.

Bar Test

1. Use the ON key or the MODE key on the keypad section to turn the instrument on and access the

main menu

2. Connect the instrument leads to any 2 motor leads

3. Use the ◄►to highlight the ROT icon screen

4. Depress the ZERO/OK key. The “Bar” Rotor Test will begin

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5. The screen displays “Measuring… Please wait” Wait until the screen changes and the instrument

issues an audible “beep” before going to step 6. Note: This may take several seconds.

6. Turn the shaft by hand until the bar appears on the display screen. This is display screen 4.

7. Continue to rotate the shaft until a percentage value appears on the right side of the display

screen. (Note: This value should be > 3% for a rotor test to be considered reliable. If the value is less than 3 the results of the rotor test may be unreliable.)

8. To check the rotor condition: a. % Value Method:

i. Turn the shaft and stop when the bar is in the middle of the display screen and the value

is 0%. If the bar does not cross zero, repeat steps 6 and 7 at a slower rate until it does cross zero.

ii. Turn the shaft until the bar moves to the extreme left side of the screen, note the

displayed value (ex - 4.5%).

iii. Turn the shaft until the bar moves to the extreme right side of the screen, note the

displayed value. (Ex 4.7%)

iv. Compare these values. If they are within 1 integer of each other, the rotor doesn’t

exhibit any issues. However values exceeding 3 integers should be investigated further.

b. Bar display method: Turn the shaft one full turn and if the bar “hangs” or “hesitates” at

either end or in the middle, there is a rotor issue and further testing should be performed.

Wave Form Test

1. While still on the Bar Test Screen (display screen 4) press the TEST key.

2. A line will be displayed across the screen. Smoothly and consistently turn the shaft; (the faster the shaft turns the more waveforms are displayed) adjust the speed until 3 or 4 complete waveforms are displayed.

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3. After several seconds the waveform will lock in place. This will be accompanied with an audible “beep”.

4. The waveform should be symmetrical and repeating, with generally rounded peaks on the top of the wave forms. (Note: If the results are unclear repeat the test at a slower speed until 2 or 3 peaks are displayed.)

5. Non-repeating or flat peaks on the waveform indicate a rotor issue.

6. Press MODE key to return to the Main Screen

7. From the Main Screen use ◄► to select PWR OFF icon

8. Press the OK key to turn the ALL-TEST PRO 31 off.

Changing the Motor Test Frequency

The default testing frequency for the ALL-TEST PRO® 31 is set at 200 Hz. This test frequency should be good for the majority of winding tests. However, there are a few instances where a different frequency may be required. The ALL-TEST PRO® 31 allows the user to select a test frequency of (25, 30, 50, 60, 100, 200, 400, or 800 Hz). The test frequency selected is not dependent on the frequency of the applied voltage to the winding. It is more dependent on the instrument making a valid measurement.

Note: Increasing the test frequency will increase the impedance measurement

Reducing the test frequency will decrease the impedance measurement.

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· Test frequencies must be changed if

1) The impedance values are less than 1 Ω or greater than 999 Ω.

2) The Fi and/or I/F values are outside of the recommended tolerances (See the Data

Interpretation Section of this manual)

Select the Motor Test

Using the ◄ F1 or ► F2, key highlight the Winding Test (Z/ψ) icon

1. Press the ZERO/OK key to select the Winding test (Z/ψ) from the main menu. This will display screen 1.

2. While display screen 1 is displayed press the F2 key. The ALL-TEST PRO® 31 will emit an audible “beep”

and the ‘1’ displayed in the upper left corner of the display screen will change to Also the value of the frequency in the lower right hand part of the display screen1 will change. In

this case it is 200 Hz.

3. Press the ▲▼buttons:

a. The applied frequency will immediately change to the new value. b. The new impedance and phase angle (Fi) values will be

displayed.

c. The display screen number returns to 1.

4. The ALL-TEST PRO® 31 frequency change is one step at a time. To change to another frequency the steps 2 & 3 must be repeated for each frequency. (Note: The test frequency can only be changed from display screen 1.)

Changing the test frequency will also change the I/F value.

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V. Additional Functions and Features

Electro-Magnetic Interference (EMI):

It is electromagnetic radiation which is emitted by electrical circuits carrying rapidly changing signals, as a by-product of their normal operation, and which causes unwanted signals (interference or noise) to be induced in other circuits. This interrupts, obstructs, or otherwise degrades or limits the effective performance of those other circuits.

NOTE: These voltages can come from cables of other energized machines lying in the same cable tray as the cables for the machine being tested.

The EMI feature of the ALL-TEST PRO® 31 measures if there is any EMI present in the motor system, which may cause errors in ALL-TEST PRO® 31 or ALL-TEST IV PRO ™ readings.

Facts about EMI:

· EMI may cause non-repeatable or unsteady test results.

· A constantly changing value for impedance during testing indicates either the shaft is still rotating or there

is EMI present from another cable.

· EMI is a ‘floating’ voltage, which will often have a value above the ground reference (0 Volts).

· The EMI may be sinusoidal depending upon the cause for the EMI (see Figure 3).

· EMI values over 1 Volt should be investigated and corrected whenever possible.

· EMI values above 10 milli-Volts may interfere with test results.

If the impedance values are constantly changing,

1st Verify that the rotor of the motor being tested is not turning, and 2nd Test for EMI using the following procedure:

Figure 3: Electro-Magnetic Induction

0.4 milli-Volts

0.2 milli-Volts

0 Volts

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1. Using the ◄► keys, select EMI from the main menu.

2. Press the ZERO/OK Key to select the EMI test.

3. The ALL-TEST PRO® 31 display screen instructs the operator to short the test leads together (These are the red & black lead), and press the ZERO/OK key. This calibrates the ALL-TEST PRO® 31 to ‘0’

4. The testing light will illuminate and 0.0 mV will be displayed on the screen. This is display screen 9.

5. Connect the winding test leads to the winding or machine that is being tested. If any EMI is present, the values that are displayed are the low and high values of the EMI, (peak & valleys) being detected.

6. Press F2/Hz key to toggle between the low & high EMI value.

Resetting the Unit

On occasion, the ALL-TEST PRO® 31 may fail to respond to keyboard, or lock up due to excessive EMI present or other reasons. Sometimes the unit may lock up during normal operation. If this occurs on units with a serial number 2028 and lower, a reset key is included in your kit.

Units with serial number 2028 & below - Reset using the included accessory reset key

1. Remove the test leads and plug the reset key into the test lead 15pin DB connector.

2. The ALL-TEST PRO® 31 will be reset to the main menu.

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3. Remove the reset key and replace in the ALL-TEST PRO® 31 carrying case. (Do not misplace the reset key, however if lost contact ALL-TEST Pro sales support for a replacement reset key).

Units with serial number 2029 & above - Reset using internal reset button:

The latest release of the ALL-TEST PRO® 31, serial numbers 2029 and higher have an internal reset button located on the top of the ALL-TEST PRO® 31. To reset the unit if it locks up, simply PRESS the reset button (highlighted below in yellow) using a paper clip, pen tip or some other small device.

VI. Charging Your ALL-TEST PRO® 31

CAUTION: The supplied charger is an integral part of the charging circuit. Using any other charger will destroy your AT31 and will VOID any warranty. If the supplied charger becomes lost or defective

contact ALL-TEST Pro sales support for a replacement.

The installed batteries are not subject to retained memory and to insure the ALL-TEST PRO® 31 is fully charged leave it plugged into the charging unit when not in use. A fully charged battery should last about 8 hours. A fully charged battery should display about 8V on the display screen with the battery charger connected to the ALL-TEST PRO 31. The operational time can vary depending on the number of insulation to ground tests performed on a single battery charge. The more Insulation resistance tests the shorter the operational time. NOTE: If the ALL-TEST PRO® 31 is not continuously

left on trickle charge it should be charged at least once a month.

To charge the ALL-TEST PRO® 31;

1. Plug the battery charging unit into the battery charging port on the top of the ALL-TEST

PRO® 31.

2. Plug the other end of the battery charging unit into the wall receptacle. The supplied charger

is universal and can be used for 120/240 V & 50/60 Hz. Simply attach the required adapter for the countries wall receptacle.

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Test Limits

Description

Impedance

Special

This result can be used to trend the condition of a winding. If the

Phase Angle (Fi)

+/- 1 point

is a winding short indicator. A result of 35, 36, 37 degrees is

Current/Frequency

+/-

2 points

I/F is a winding short indicator. A result

of -44, -45, -46 would be

Phase Balance

+/- 5% Indicates winding unbalance which will result in current unbalance,

Insulation

See Table 2 and

Indicates ground wall insulation failure or severe winding

Motor Voltage Rating

Insulation Test Voltage

< 1000

Volts AC

500 V

1000 to

2500

Volts AC

1000 V

2501 to 5000 Volts AC

1000

- 2500 V

3. When charging the charging indicating light will be illuminated red.

4. The display screen will provide the instruments condition during the charge. The data on the

screen will identify information on the battery charge including length of time on charge, battery voltage level and battery temperature.

5. The battery charge indicating light will turn green when fully charged. If the unit is not being

used, it is recommended that the unit be left on a trickle charge.

VII. Data Interpretation Three Phase Motors

The basic tolerances for the ALL-TEST PRO® 31 are the same as the ALL-TEST IV PRO™,

Data Interpretation Tables

During testing with the ALL-TEST PRO® 31 if a fault is detected using the interpretation tables, review all of the additional data interpretation consideration before issuing a pass/fail on the winding tested. When making repair/replace decisions it is also important to evaluate the specifics of the application, such as: Is the motor in a critical application, what are the operating conditions, environment, etc.?

Table 1: Three Phase Motor Test Results

overall readings decrease significantly, between tests, then the winding is degrading or contaminated.

OK, a result of 35, 32, 32 would be a fault (shorted winding). This value should be greater than 15 degrees.

(I/F)

Resistance

OK, -44, -46, -46 is borderline and -42 -45, -45 would be a fault (shorted winding). These readings should be between -15 and -50.

motor heating and poor starting. It is recommended that this value remains under 3% with 5% indicating a fault.

contamination.

Table 2: Insulation Resistance Voltage

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Application

Pass/Fail Value

Insulation systems prior to 1974

> 1 Meg

-Ohm + 1 Meg

Ohm per kV rating of motor

Random Wound motors less than 600 V

> 5 MegOhms

DC Armatures and Form Wound motors over 600 V

> 100 MegOhms

Table 3: Insulation Resistance Values (IEEE 43-2000)

Additional Data Interpretation Considerations Three Phase Motors

There are three additional considerations when using an ALL-TEST PRO® 31:

· Test location

· Rotor windings

· Confirming winding faults

Test Location

If a fault is detected when testing from the motor control center, motor disconnect, or from any distance away from the motor through cabling, it is important that a confirmation test be performed at the motor connection box prior to condemning a winding. Note: ALL-TEST PRO® MCA instruments will detect

cable faults.

· If the readings are good at the motor during the confirmation test, then the fault may be in the cable.

· If the reading improves, but is still poor, at the motor, then there may be a fault in both the motor and cable.

· If the reading shows similar results at the motor, then the fault exists in the motor.

Rotor Windings

In the case of synchronous motors or generators that have windings in the rotor, if a fault is detected with the ALL-TEST PRO® 31, rotate the shaft any amount and retest. If the readings change, or move with the repositioning of the rotor, then the fault will most likely be found in the rotor windings.

If the readings remain the same then the fault is most likely in the stator. In addition to the recommendations from the next section, also see pages 34-35.

Confirming Suspected Winding Shorts

Experience has shown that for most three phases, AC, squirrel cage, inductions motors, 200 Hz are the best frequency at which to test the condition of the windings. However in some cases, due to the permeability of the rotor or stator core, the rotor design, air gap, winding configuration or rotor position, the default frequency may provide a false negative at 200 Hz. However, we have found that if the winding appears good at any frequency it is generally a good winding.

Note: The these guidelines are generic and hold true for identifying developing winding shorts for most applications. However, it may be necessary to compare reading to like motors.

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If the winding test indicated a developing winding short, based upon an unbalance in phase angle (Fi) and/or Current Frequency Response (I/F) and:

1. Impedance is balanced (<3% from average) then a variable frequency test should be

performed. (See variable frequency test below)

2. Impedance is unbalanced (>3% from average) then a rotor compensated test should be

performed. (See rotor compensation test below)

The test results, such as those found in Table 4, indicate a potential winding fault as Fi is out by more than 1 from average:

Table 4: Sample Test Results

T1-T2 T1-T3 T2-T3

Fi 66 67 69

I/F -44 -44 -45

Method 1: Rotor Compensation

Note: This test was developed for the ALL-TEST Pro kit using the ALL-TEST PRO IV™. Using the ALL-TEST PRO® 31 & the ALL-TEST PRO IV™ together is the best method available for simply and accurately determining the condition of the windings in AC 3 phase induction motors.

One of the reasons for the result shown in Table 4 may be a rotor position or a rotor anomaly, such as severe casting voids, rotor eccentricity, etc. To separate a rotor fault from a winding fault it is necessary to perform a rotor compensation. Use the procedure listed below to perform the rotor compensation test:

1. With the Instrument test leads connected to T1 & T2. From display screen 1, turn shaft until

the maximum impedance value is obtained.

2. Read and record the impedance and phase angle reading from display screen 1.

3. Depress the TEST key to read and record the I/F value.

4. Move the Test leads to T1 & T3, turn the shaft until the maximum impedance value is

obtained on this phase.

5. Read and record the impedance and phase angle reading from display screen 1.

6. Depress the TEST key to read and record the I/F value.

7. Move the Test leads to T2 & T3, turn the shaft until the maximum impedance value is

obtained on this phase.

8. Read and record the impedance and phase angle reading from display screen 1.

9. Depress the TEST key to read and record the I/F value.

The results should be +/- 1 digit from the average, and the I/F values should be within +/- 2 units from average.

Method 2: Variable Frequency Test

The variable frequency test is used to confirm winding faults if the impedance readings are balanced. It is recommended to test the winding at 400 Hz, 100Hz, 50 Hz and 25 Hz. If it tests “good” at any of

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these frequencies then it is generally a good winding (follow the procedure for changing the test frequency).

Example 1. If the test results remain similar, meaning that the actual readings may change by a few digits, but the difference between the readings remains the same, then the winding is considered good; In Table 4 the test spread of the Fi is 3 units, 66 to 69, after changing. At the test frequency, the results in Table 5 show the Fi values changed from 70 to 73. The spread is still 3 units. This is generally a “good” winding

Table 4: Sample Test Results

T1-T2 T1-T3 T2-T3

Fi 66 67 69

I/F -44 -44 -45

Table 5: Adjusted Frequency Sample, Good

T1-T2 T1-T3 T2-T3

Fi 70 71 73

I/F -44 -44 -45

Example 2. If the unbalances of Fi and/or I/F at the other test frequency increase then the winding is most likely in poor condition. In table 4, the spread of Fi is 3 units, 66 to 69, after changing. At the test frequency, see Table 6, the Fi values changed from 70 to 75. Then the spread has increased to 5 units. This winding should be considered to be in poor condition.

Table 6: Adjusted Frequency Sample, Bad

T1-T2 T1-T3 T2-T3

Fi 70 71 75

I/F -45 -45 -47

VIII. DC Motor Testing

Electrical testing of DC motors is a challenge, and the ALL-TEST PRO® 31 can provide some limited troubleshooting capabilities for them. However, for a more detailed and thorough analysis, we suggest you use the ALL-TEST IV PRO™. One of the key issues is the inability to compare like coils. However, it is possible to do some limited comparisons of coils, (if the information is available). Trending changes over time is also possible, as well as measuring & trending insulation resistance to ground of both the field and the armature windings.

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Testing an Assembled DC Motor

Connect the ALL-TEST PRO® 31’s ground lead (yellow lead) to an earth ground at the test point.

Series DC motor

DC series motors provide a special problem since the series field is constructed of a few turns of very large wire to handle the high current through the armature and field. This combination provides a very low impedance value. The best method of testing this type of motor is by trending, looking for changes, particularly I/F and phase angle (Fi).

Testing Series Field

1. Connect the instrument test leads to motor series field leads S1 & S2.

2. Select the Motor Test from the main menu (see Winding Test section).

3. Adjust the test frequency to get the impedance value above 1 Ohm and below 999 Ohms.

4. Record the test frequency, impedance and phase angle readings.

5. Compare these results to series field readings from a similar motor or to a baseline reading on the same motor and note any changes.

Testing the Armature Field See the Armature Testing section below.

For Interpretation: See the DC Motor Analysis section on page 34

Compound or Shunt DC motor

Testing Shunt Field

1. Connect the instrument test leads to shunt field connectors F1 & F2.

2. Select the Motor Test from the main menu (see Winding Test section).

3. Adjust the test frequency to get the impedance value above 1 Ohm and below 999 Ohms.

4. Record the test frequency, impedance and phase angle readings.

5. Compare these results to readings from a similar motor or to a baseline reading on the same motor and note any changes.

Testing the Armature Field See the Armature Testing section below.

Armature Testing

DC armatures are time consuming but relatively easy to test. There are three basic methods of testing DC armatures.

· Trending

· Assembled

· Disassembled

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TRENDING

Series Motor-Connect the instrument test leads to A1 & S2, record and trend Impedance, Phase angle and I/F. Impedance reading will vary with temperature, and is important that comparative reading are taken at the same temperature. If the impedance is decreasing with time the armature winding are either contaminated or degrading. Changes in phase angle and I/F signify winding shorts.

ASSEMBLED

1. Connect the instrument test leads to the A1 and A2 armature leads.

2. Lift all but two of the DC motor brushes 90 degrees from each other.

3. Select the Motor Test from the main menu (see Winding Test section).

4. Adjust the test frequency until you are between 1 and 999 Ohms of impedance.

5. Position the leading edge of one of the brushes at the edge of one rotor bar. Note the impedance and phase angle values.

6. Repeat step 6 until you have completed one full revolution.

7. If the impedance values are consistent and/or repeating, the armature is good. If not, there is a short.

Note: This test can also be performed using I/F (Screen 2) and % Deviation (Screen 3).

DISASSEMBLED

1. Connect the instrument ATF 1100 Armature Test Forks.

2. Select the Motor Test from the main menu (see Winding Test section).

3. Separate the Armature Test Forks to approximately 90 degree span of the commutator. Lock the test fork span by tightening the locking handle on the test fork. (If the commutator is too large expand the test forks to their maximum dimension).

4. Mark one of the commutator segments as the starting point.

5. Place one of the test forks on the marked commutator segment; place the other test fork on the commutator segment determined by step 3 above.

6. Adjust the test frequency until you are between 1 and 999 Ohms of impedance.

7. Read and record the impedance value from the ALL-TEST PRO 31 display screen.

8. Repeat step 6 until you have completed one full rotation around the commutator.

9. If the impedance values are consistent and/or repeating, the armature is good. If not, there is a short.

Note: This test can also be performed using I/F (Screen 2) and % Deviation (Screen 3).

DC Motor Analysis

DC field coil analysis is performed by using one of three methods:

1. Trend – Trend the windings over time or compare to a past reading. The Fi and I/F readings should be within one digit from the baseline reading.

2. Compare – Two similar DC motors (same manufacturer and model) can be compared to each other. The Fi and I/F readings should be within one digit of each other.

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3. Split the fields – Evenly split the fields and compare the test results. The Fi and I/F readings should be within one digit of each other.

The DC armature can be evaluated using one of three methods:

1. Trend – the overall armature circuit reading is trended over time. The Fi and I/F should not

change more than one digit.

2. Compare – Compare the armature results from two similar DC motors (see above) to each other.

The Fi and I/F readings should be within one digit of each other.

3. Bar to bar testing – The test results should show as a repeating pattern.

IX. Additional Test Methods

Wound Rotor Motors

When testing a wound rotor motor, the stator coils and rotor coils must be tested separately. The procedure below must be followed, or results will not be reliable.

When testing the stator coils, the three phases of rotor coils must be shorted together and connected to an earth ground to “bleed off” circulating currents induced by the stator. Data interpretation rules are the same as for induction motors as shown on page 29.

Rotor coils are tested through the slip rings. All three stator phases must be shorted together and grounded. Once again, data interpretation rules are the same as for induction motors as shown on page

29.

Wye-Delta Motors

Wye-Delta motors are often found on large chillers as well as in other applications. They will have six leads numbered T-1 through T-6, all running to the motor control center. When testing this type of motor, use the following connection sequence:

Phase 1 T1 to T4 Phase 2 T2 to T5 Phase 3 T3 to T6

Note that testing T1-T2, T1-T3, and T2-T3 will normally show open phases (no continuity).

MegOhm testing should be performed on each of the three phases.

Data interpretation rules are the same as for induction motors as shown for on page 29.

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Capacitor Testing

Note: This is a Pass/Fail test.

Motor starting capacitors and power factor correction capacitors can be effectively tested with the ALLTEST PRO® 31. This test will not provide the capacitance value of the test specimen, but will indicate if the capacitor is performing properly in an AC Circuit.

1. Turn line power off. Disconnect one capacitor lead from the circuit.

2. Short the capacitor terminals to remove any remaining charge.

3. Put the ALL-TEST PRO® 31 in “winding test” mode by selecting the Motor icon from the mode screen.

4. Connect the red and black test leads to the capacitor.

5. An impedance value should be displayed. If impedance value shows “---”, the capacitor is open.

6. Observe the phase angle measurement in the upper right of the display. If the capacitor is good, this number is very close to 90.

7. Press the TEST key. For a good capacitor, the main display will show 90 or above. A reading below 90 indicates a poor or failed capacitor.

8. Turn the instrument off.

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X. Tech Support and Information

Technical support can be obtained by emailing or faxing your questions to ALL-TEST Pro, LLC at:

Email: support@alltestpro.com Fax: 860-399-3180

Please put “AT31 Tech Support” in your subject line.

XI. Available Accessories for the ALL-TEST PRO® 31

ATF1100 DC Armature Test Fixture AT3402-4 Condition Calculator™ 4.0 Software ATM2000 Motor Fault Training Motor

XII. Training Class

AT-MCCLASS Motor Diagnostics Workshop

For more information contact ALL-TEST Pro, LLC at: Phone: 860-399-4222 Website: www.alltestpro.com (lists the schedule) Email: CE@alltestpro.com

ALL-TEST Pro, LLC

121 Spencer Plain Rd

PO Box 1139

Old Saybrook, CT 06475

Phone: 860-399-4222

Toll Free Phone: 800-952-8776

Fax: 860-399-3180

Email: support@alltestpro.com

Web: www.alltestpro.com

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ALL-TEST Pro 31 Motor Test Form

Motor ID: Location: Test Date: Test Frequency

Impedance (Z) Phase Angle (°) Z-Test or I/F Phase balance (opt)

Ins Resistance

Was rotor set to lowest value during phase balance test? Y__ N__

Rotor test performed? Y___ N___

Comments:

ALL-TEST Pro 31 Motor Test Form

Motor ID: Location: Test Date: Test Frequency

Impedance (Z) Phase Angle (°) Z-Test or I/F Phase balance (opt)

Ins Resistance

Was rotor set to lowest value during phase balance test? Y__ N__

Rotor test performed? Y___ N___

Comments:

Phase 1-2

Phase A-B

Phase 1-3

Test Voltage

Phase A-C

Test Voltage

Phase 2-3

Phase B-C

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Specifications and Main Features

Frequently Asked Questions

User Manual