Vanguard CT-7500 User Manual

OPERATING INSTRUCTIONS

For the

Model CT-7500

A Digital Circuit-Breaker Analyzer

Manufactured by

Vanguard Instruments Co., Inc.

1711 Grevillea Ct.

Ontario, California 91761

TEL: [phone] Jan 2001
FAX: [phone] Rev 2

MODEL CT-7500 OPERATING INSTRUCTIONS

TABLE OF CONTENTS

1.0 INTRODUCTION…. …..

2.0 CT-7500 DESCRIPTION

2.1 On-Line Timing (Quick-Shot) Mode

2.2 Time-Versus-Travel Circuit Breaker Analyzer Mode

2.2.1 Contact Timing Channels

2.2.1 Analog Voltage Monitoring Channel

2.2.3 Digital Voltage Monitoring Channel

2.2.4 Trip/Close Current Monitoring

2.2.5 Travel Transducer Input Channels

2.2.6 Breaker Initiate Capability

2.2.7 Built-In Thermal Printer

2.2.8 Printer Port

2.2.9 Computer Interface Capabilities

2.2.10 Timing Shots Storage Capabilities

2.2.11 Breaker Test Plan Storage Abilities

2.2.12 Diagnostic Capabilities

2.2.13 CT-7500 Display Control Switches

3.0 TEST RESULTS TABULATION

3.1 Electrical Measurement Results

3.2 Mechanical Measurement Results

3.3 Analog Voltage Input Results

3.4 Digital Voltage Input Results

3.5 Initiate Current Results

3.6 Slow-Close Test

4.0 TEST-RESULT GRAPHICS

4.1 Thermal Printer Graphic Printout

4.2 Ink-Jet Printer Output

5.0 CONTROLS AND DISPLAY

6.0 CT-7500 ANALYZER SPECIFICATIONS

7.0 CT-7500 SPECIAL FEATURES

7.1 CT-7500 Operating Voltage

7.2 CT-7500 Main Power Fuse

7.3 CT-7500 Printer and Printer Paper

7.4 CT-7500 Printer Paper Control

7.5 Replacing CT-7500 Thermal Paper

7.6 CT-7500 LCD Contrast Control

8.0 TEST HOOKUP CONNECTIONS

8.1 Contact Cable Hookup

8.2 Initiate Cable Hookup

8.3 Analog Voltage Monitor Hookup

8.4 Digital Voltage Monitor Hookup

8.5 External Trigger Input

8.6 AC Current Sensor Hookup

9.0 OPERATING PROCEDURES

9.1 Timing a Circuit Breaker

9.1.1 Timing an Open Operation With No Resistor

9.1.2 Timing an Open Operation With Insertion Resistor

9.1.3 Timing Close-Open Operation Using Channel #1

9.2 Get Tabulated Results Using Thermal Printer

9.3 Get Graphic Timing Results Using Thermal Printer

9.4 Save Timing Shot in EEPROM

9.5 Print EEPROM Timing Shot Directory

9.6 Recall a Timing Shot

9.7 Deleting a Timing Shot

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MODEL CT-7500 OPERATING INSTRUCTIONS

9.8 Recall a Breaker Test Plan

9.9 Print a Breaker Test Plan

9.10 Print Breaker Test Plan Directory

9.11 Shot Description

9.12 CT-7500 Channel Configuration

9.13 Computer Interface

9.14 Breaker Travel Analysis

9.14.1 Breaker Stroke

9.14.2 Breaker Over-Travel Distance

9.14.3 Breaker Bounce-Back Distance

9.14.4 Contact Wipe

9.14.5 Breaker Contact Velocity

9.14.6 Analysis Point Selection

9.14.7 Analysis Point No 1

9.14.8 Analysis Point No 2

9.15 Set-Up Open Timer Analysis Points

9.16 English/Metric Selection

9.17 Set CT-7500 Internal Clock

9.18 Slow-Close Test

9.19 Transducer Self Test

9.20 Check Cable Hookup

9.21 Automatic Print Setting

10.0 Running the CT-7500s in Tandem

11.0 CT-7500 Trouble Shooting Guide

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APPENDIX

A. ITE Circuit Breaker Model 14.4K Timing Chart
B. CT-7500 Test Plan for ITE Circuit Breaker Model 14.4K.
C. CT-7500 Timing Chart for ITE Circuit Breaker Model 14.4K.
D. CT-7500 Tabulated Test Report for ITE Circuit Breaker Model 14.4K.
E. Timing Chart for Siemens TCP-149 Circuit Breaker
F. CT-7500 Test Plan for Siemens TCP-149 Circuit Breaker

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MODEL CT-7500 OPERATING INSTRUCTIONS

LIST OF FIGURES

Figure 5-1. CT-7500 Control Panel
Figure 8-1. Typical Circuit-Breaker Test Cable Hookup
Figure 8-2. Typical Series Contacts Test Cable hookup
Figure 8-3. Typical Dc Trip and Close Control Test Cable Hookup
Figure 8-4. Typical DC Trip and AC Close Control Test Cable Hookup
Figure 8-5. Typical Voltage-Monitoring Test Cable Hookup
Figure 8-6. Typical External Trigger Hookup
Figure 8-7. Transducer Cable Hookup
Figure 8-8. AC Current Sensor Hookup
Figure 9-0. CT-7500 Operating Steps
Figure 9-1. Steering Map of Menus and User Options
Figure 9-2. Typical Tabulated Printout of Open Operation on Thermal Printer
Figure 9-3. Typical Tabular Printout of Open Operation on Ink-Jet Printer
Figure 9-4. Typical Graphic result on Thermal Printer
Figure 9-5. Typical Graphic report on Ink-Jet Printer
Figure 9-6. Typical Graphic-Expansion result Printout on Thermal Printer
Figure 9-7. Open and Close Timing Graph Interpretation
Figure 9-8. Open-Close and Close-Open Graph Interpretation
Figure 9-9. Typical Timing Shot Directory Printout on Thermal Printer
Figure 9-10 Typical Test-Plan Printout on Thermal Printer
Figure 9-11 Typical Test Plan Directory Printout
Figure 9-12 Typical Slow-Close Test Report

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LIST OF TABLES

Table 5-1 Model CT-7500 Controls and Display
Table 7-1 Voltage Selection Jumper Setting
Table 9-1. Open Operation with No Resistor
Table 9-2. Open Operation with Insertion Resistor
Table 9-3. Close-Open Operation with No Resistor
Table 9-4. Get Tabulated Results
Table 9-5. Plot Chart and Tabulated Report
Table 9-6. Save Timing Shot in EEPROM
Table 9-7. Print Timing Shot Directory
Table 9-8. Recall a Timing Shot
Table 9-9. Delete a Timing Shot
Table 9-10.Recall a Test Plan
Table 9-11.Print a Breaker Test Plan
Table 9-12.Print a Breaker Test Plan Directory
Table 9-13.Entering Shot Identification Header
Table 9-14.Select Channel Configuration
Table 9-15.Selecting or Aborting Computer Control
Table 9-16.Setting Up "OPEN" Analysis Points Using Distance
Table 9-17.Select Metric Units of Measure
Table 9-18.Setting the Clock and Calendar
Table 9-19.Programming a Slow-Close Test
Table 9-20.Performing a Transducer Self Test
Table 9-21.Checking the Cable Hookup
Table 9-22.Automatic Print Setting

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MODEL CT-7500 OPERATING INSTRUCTIONS

MODEL CT-7500 OPERATING INSTRUCTIONS

1.0 Introduction

The Model CT-7500 is a microprocessor-based digital time-versus-travel Circuit Breaker
Analyzer with a special on line test mode. This on line test mode (Quick-Shot mode) allows the
user to capture breaker contact close time and contact open (clear) time while the breaker is still in
service. In the off line test, the Model CT-7500 fully analyzes utility circuit-breaker performance:
contact time, stroke, velocity, over-travel, bounce-back, and contact wipe.

Contact-motion analysis includes: Open, Close, Open-Close, Close-Open, and Open-Close­Open. A timing window is selectable between 1-second or 10-second periods. The 10-second
window allows timing of long events (e.g., circuit switcher contacts).

The CT-7500 is available in three models:

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CT-7500-3; three contact channels.

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CT-7500-6; six contact channels.

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CT-7500-12; twelve contact channels.

All the CT-7500 models have the following input:

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Three Digital Travel Transducer Input channels.

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One Analog Voltage Monitor Input channel.

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One Digital Voltage Monitor Input channel.

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One Trip/Close current monitor channel.

There are two modes of operation for the CT-7500: Stand Alone Mode and Computer Control
Mode. This manual will focus on the CT-7500 Stand Alone Mode. The Computer Control Mode is
covered under the CT-7500 PC software manual.

2.0 CT-7500 Description

2.1 On-line Timing (Quick-Shot) mode

A clamp-on AC current probe connected to the breaker bushing CT lets the CT-7500
measure breaker switching time (while the breaker’s still in service). The CT-7500 can time an
OPEN operation by sensing the time when the OPEN coil is energized until the bushing CT
current returns to zero. CLOSE time is detected when the close coil is energized until the bushing
CT current is detected.
This “Quick-Shot” mode provides a quick way to diagnose breaker performance and savings in
maintenance cost.

2.2 Time-Versus-Travel Circuit Breaker Analyzer Mode

The CT-7500 applies a 35Vdc voltage to each of the contact channels. This test voltage is
sensed by an analog to digital converter (A/D) to determine the state of the contact (close, or
open, or insertion resistor). The CT-7500 records the A/D reading at a 10 KHz rate, and stores
these readings in memory. The contact/resistor time is then derived from data stored in memory.

The CT-7500 uses three up-down counters to sense the breaker’s transducer reading. The
CT-7500 travel transducer employs an optical encoder to send quadrature signals to the CT­7500’s counters. With the use of the digital transducer and counters, the user never has to set up

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MODEL CT-7500 OPERATING INSTRUCTIONS

or calibrate the transducer.

The CT-7500 has a built-in initiate circuit to operate circuit breakers. Since this solid-state
circuit is controlled by the micro-processor, the CT-7500 can perform multiple operations (O-C, C­O, O-C-O) with ease. Each Trip and Close initiate circuit is fuse protected. The user is also
required to hold the “ARM” switch during a test to complete the initiate circuit.

The CT-7500 can also store up to 200 breaker-timing test records and 45 breaker test-plans in
FLASH EEPROM. Stored timing test records can be recalled and printed or transferred to the PC.
Using the breaker test plan during a test, the users do not have to set the velocity calculating
points. The CT-7500 will also print “PASS” and “FAIL” results on test report.

2.2.1 Contact Timing Channels

A breaker's interruption of contacts is timed with the dry-contact input channels. Each channel

can detect the main contacts and insertion resistor contacts times (in millisecond and cycles).

Note

The CT-7500 can detect insertion resistors in a 10-7000 ohm range. Resistances over 7000
ohms are detected as an open contact.

2.2.2 Analog Voltage Monitoring Channel

An analog voltage input is dedicated to monitoring a breaker's dc power supply or coil voltages

(0-255 V dc or peak ac).

Note

Input voltage range is 0-300Vdc or peak AC. Reading range is 0-255Vdc.

2.2.3 Digital Voltage Monitoring Channel

One digital voltage input channel monitors voltage on/off status. Voltage threshold from 30-255
Vdc is considered as “ON” status. Voltage threshold less than 30 Vdc is considered as “OFF”
status.

2.2.4 Trip/Close Current Monitoring

A built-in Hall-effect sensor records Trip and Close coil current levels and duration. The
breaker's operate coil current waveform is graphically plotted on a printout. Current reading is also
printed in the tabulated report.

2.2.5 Travel Transducer Input Channels

Each CT-7500 has 3 digital transducer input channels. These transducer channels require
neither setup nor calibration.

2.2.6 Breaker Initiate Capability

A built-in solid-state initiate device lets users operate a breaker from the CT-7500. Operational
modes include: Open, Close, Open-Close, Close-Open, Open-Close-Open. Multiple operations

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MODEL CT-7500 OPERATING INSTRUCTIONS

(e.g., Open-Close, Close-Open, Open-Close-Open) can be initiated with a programmable delay
time or by sensing the breaker's contact state.

Because solid-state switching is used in the initiate circuitry, the CT-7500 can switch a
breaker's ac or dc control circuit. Each trip and close circuit is protected by a 3-ampere fuse. The
initiate circuit is also protected by an interlock "ARM" switch.

2.2.7 Built-in Thermal Printer

A 4.5-inch wide thermal printer prints the breaker's contact analysis results in both tabular and
graphic formats.

2.2.8 Printer Port

A parallel printer port can drive a H-P color ink-jet printer, from which a color graphic of timing
charts and tabulated results can be printed on 8½-11-inch paper.

An Ink-Jet printer is supplied with each CT-7500.

2.2.9 Computer Interface Capabilities

A built-in RS-232C port lets timing shots stored in CT-7500 EEPROMs to be down-loaded to an
IBM-compatible PC. Windows-based (Windows 95, Windows 98, Windows Me, Windows 2000,
and Windows NT) Breaker Analysis Software is supplied with the CT-7500. This software allows
the user to:

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Time Circuit breakers from a PC.

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Retrieve timing shots stored in CT-7500.

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Recall timing shots from a hard drive for re-analysis (at an office PC).

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Create breaker test plans on a PC and load into the CT-7500.

2.2.10 Timing Shots Storage Capabilities

The CT-7500 uses Electrical Erasable PROMs (EEPROM) to store timing-shot data. Unlike
other media, EEPROMs are immune to temperature, shock, and humidity. Stored shots can be
recalled to reanalyze test data, to re-print test reports, or transfer data to an IBM compatible PC
for record keeping. Up to 200 timing shots can be stored in the EEPROMs. The number of shots
stored in EEPROMs can vary, depending on the size of the shot records.

2.2.11 Breaker Test Plan Storage Abilities

Up to 45 breaker’s test plans can be stored in the CT-7500. Test plans comprise breaker
specifications (i.e., stroke, velocity, contact time). By recalling and using a test plan, operators
can immediately test breakers and view a pass/fail report (made by comparing test performance
with specifications in the test plan). Breaker specifications need not be referenced to compare
test results to determine if a breaker passed.

A breaker test plan can be created by using the Breaker Analysis Software (supplied with each
CT-7500). The test plan is then loaded into the CT-7500 via an RS-232C serial port.

2.2.12 Diagnostic Capabilities

The CT-7500 can run diagnostics on its own electronics. Self-testing of contact cable hook-ups
and transducers lets users checkout CT-7500 accessories whenever verification is required.

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MODEL CT-7500 OPERATING INSTRUCTIONS

2.2.13 CT-7500 Display and Control Switches

An alpha-numeric keypad lets the user enter breaker’s name plate data (Substation name,
Breaker Model, etc) and control function. A 4-line by 20-character LCD readout displays user
messages. The LCD is back lighted so messages can be viewed in low light levels.

3.0 Test Result Tabulation

3.1 Electrical Measurement Results

Each CT-7500 contact channel provides the following test results:

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Contact Close time, (Quick-Shot) Mode.

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Contact Open (Clear) time, (Quick-Shot) Mode.

The CT-7500 can detect insertion resistors in a 10-7000 ohm range. Resistances over 7000
ohms are detected as an open contact.

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Main contact and insertion resistor contact times (Time-Travel Test).

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Contact bounce time (Time-Travel Test).

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Contact spread time (Time-Travel Test).

NOTE

3.2 Mechanical Measurement Results

Each digital transducer channel provides the following test results:

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Breaker stroke (Time-Travel Test).

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Over travel (Time-Travel Test).

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Bounce back (Time-Travel Test).

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Contact wipe (Time-Travel Test).

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Velocity (Time-Travel Test).

Breaker contact speed calculation is based on a contact's travel distance over a period of time,

which is defined by the manufacturer's specifications.

A CT-7500 not only calculates simple distance-over-time speeds, but can also support other

formulas. An example is Siemen TCP breaker calculation formula:

V=12.2 x a/b

The formula and analysis points can be stored in a test plan for use later in the field.

NOTE

If operators use a breaker test plan (see paragraph 9.8) during testing, the test report will also
indicate a Pass/Fail condition for each test parameter (i.e. contact time, stroke, velocity, etc.).

3.3 Analog Voltage Input Results

The analog voltage input channel (V1) measures the breaker's dc control voltage during
operation. Printed voltage readings include nominal voltage (supply voltage at no load) and
minimum voltage (supply voltage under load or when a coil is energized).
This connection allows the user to monitor the DC power supply voltage fluctuation during
breaker’s operation. This feature is handy to detect breaker’s power supply problem; which

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MODEL CT-7500 OPERATING INSTRUCTIONS

normally can not be seen using a volt meter.

NOTE

Voltage reading range is 1.0-255 V dc.

3.4 Digital Voltage Input Results

The Digital Voltage Input channel (V2) monitors voltage on/off conditions and graphs the result.
A voltage level above 30Vdc is considered as “ON” condition. This input channel is dedicated to
monitor breaker’s auxiliary switch action during breaker’s operation.

NOTE

Input voltage range is 1.0-300 V ac/dc.

3.5 Initiate Current Results

The CT-7500 not only plots Trip or Close current waveforms, but also prints steady-state
current readings of trip and close coils during operation.

NOTE

1. If the CT-7500 initiates the OPEN test or CLOSE test under the Quick-Shot test, the test report
will show OPEN or CLOSE coil current reading and current wave form.

2. If the user operates the breaker for the Quick-Shot test (external trigger), no coil current reading
or waveform will be recorded.

3.6 Slow-Close Test

A slow-close test finds the contact touch distance and penetration by using the travel
transducer and dry contact channels.

4.0 Test-Results Graphics

4.1 Thermal Printer Graphic Printout

A 4.5” wide built-in thermal printer prints graphic waveforms of contact channels, travel curves,
and actuator-coil currents. With a zoom graphics mode, the user can select an enlargement by
specifying the timing zone.

4.2 Ink-Jet Printer Output

A color graphic report can be printed on the HP Ink-jet printer (supplied with each CT-7500).
The CT-7500 will print color graphics of contact channels, travel channels, current waveforms on
8½- by 11-inch paper.

5.0 Controls and Display

(See Figure 5-1 and Table 5-1.)

Before using the CT-7500 Analyzer, users should become familiar with all of its controls and
display indications. The keypad and display are used to operate the CT-7500 Analyzer. Figure 5­1 shows the control panel and numbered lines pointing to each control and indicator. The line
numbers refer to Table 5-1, which describes the function of each control and indication.

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Figure 5-1. CT-7500 Control Panel

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Table 5-1. Model CT-7500 Controls and Displays

Fig. 5-1
Index no. PANEL MARKING

FUNCTIONAL DESCRIPTION

1

2

3

4

5

6

7

8

9

CONTACT INPUT (1-12) Connector, 3-pin: each input is a continuity (dry)

sensor for detecting a contact closing or opening (a
timing input to the processor).

(30V-300V) VOLTAGE

V1 & V2/ VOLTAGE INPUT

TRIGGER/VOLTAGE INPUT Connector, 3-pin: input (30-300 Vac, dc, or peak)

CT AC current sensor input channel.

AC 100-240V; 5A MAX Power plug (3-wire), ac fuse, ON/OFF switch: Switch

GROUND Stud, 5/16-18 threads, with wing nut; safety ground

TRANSDUCER INPUT

(T1, T2, T3)

(Printer; No panel marking) Thermal printer; prints on specially treated 4½-inch

PRINTER Printer port connector, 25-pin.

Connector, 3-pin: each input is a voltage detector for
timing voltage (30-300 V dc/peak) of trip or close coil
switching (active period).

triggers timing functions.

is 2-pole rocker, input power on & off.

terminal.

Connector, 16-pin: each input (T1-T3) is a Travel
Encoder output (contact motion data).

wide paper; processor controlled.

10

11

12

13

14

15

1-9, 0, ENTER, START, STOP,
CLEAR, ↑ PAPER LCD,

PAPER LCD

↓

REMOTE ARM SWITCH Remote Arm Switch connector. The remote Arm

"PUSH" TO ARM Pushbutton switch, spring-loaded: press & hold to

(Display; no panel marking) Liquid-Crystal Display (LCD), back lighted: 4-line by

CLOSE/ 3 A Close circuit fuse (3 amperes).

OPEN/ 3 A Open circuit fuse (3 amperes).

Keypad, 16-key; keys are momentary-contact
pushbutton switches: makes menu selections, enters
alpha-numeric data, adjusts LCD contrast, and
moves paper.

switch with a 15ft cable is provided with each CT-

7500.

complete trip & close circuits for breaker tests.

20 characters per line: displays menus, options,
prompts, and test-result data.

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Table 5-1. Model CT-7500 Controls and Displays (cont’)

Fig. 5-1
Index no. PANEL MARKING

FUNCTIONAL DESCRIPTION

16

17

INITIATE Connector, 4-pin; switching circuit for operating the

circuit breaker being tested.

RS-232C Connector, 9-pin:RS-232C computer interface.

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6.0 CT-7500 Analyzer Specifications

CONTACT TIMING

SIZE & WEIGHT

OPERATING POWER

AC CURRENT SENSOR

DRY-CONTACT INPUTS

TIMING WINDOW

RESOLUTION

DRY-CONTACT
CHANNEL PROTECTION

CONTACT RESISTANCE

INSERTION RESISTANCE

TRIGGER INPUT

Open, Close, Open-Close, Close-Open, and Open-Close-Open

16d by 14w by 11h (inches); Less than 32 pounds

3 amps, 90-120Vac/200-240Vac 50/60 Hz

0-25 Ampere, non-contact AC current sensor

3, 6, or 12 dry-input channels; Each detects Main & Insertion-Resistor contacts

Selectable: 1 second or 10 seconds

± 100 microseconds at 1-second duration; ±1.0 millisecond at 10-seconds duration

Fuses protect all isolated power supplies; All contact inputs are grounded until test;

Inputs are MOV protected

CLOSED: <20 ohms; OPEN: >10,000 ohms

Range: 10 to 7,000 ohms

Open/Close: 30 to 300 volts, dc or peak ac

(See table below.)

VOLTAGE INPUTS

CURRENT-SENSOR INPUT

BREAKER INITIATE

TRAVEL TRANSDUCERS

CONTACT TRAVEL
POINT DIFFERENCE

BREAKER ANALYSIS

display,

SOFTWARE (included)

COMPUTER INTERFACE

DISPLAY

HARD-COPY PRINTOUT

COLOR PRINTER

Two: 1.0-300 volts, dc/peak ac; analog voltage recording 1.0-255 V dc

One: Non-contact, Hall-Effect sensor, 0.2 to 25 amp ranges, dc to 5 kHz

Initiate Open, Close, Open-Close, Close-Open, Open-Close-Open

3 travel-transducer channels; Linear motion: 0.0-60.0 (±0.01) inches;
Rotary Range: 0-360o (± 0.36

Measures"Slow-Close" contact point distance (Hard Copy)

Analysis software runs on IBM-compatible. Software package for graphic

numerical reports, and database utility for shop or office

RS-232C Port

Back-lighted LCD screen: 4 lines by 20 characters, sunlight viewable

Contact travel waveforms & tabulated results print on 4.5-inch thermal paper

Built-in parallel printer port. CT-7500 produces both graphic and tabulated test
results in color on 8.5 by 11 (inches) paper via external ink-jet printer

o)

CARRYING CASE (optional)

Hard shipping case for both CT-7500 and Travel Transducer

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WARRANTY

One year warranty on parts and labor; post-warranty service contracts available

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7.0 CT-7500 Special Features

7.1 CT-7500 Operating Voltages

The CT-7500 operating voltage is selectable between 110/120 V, 50/60 Hz or 220/240 V,
50/60 Hz. Voltage selection is set by one jumper/connector on the Initiate PCB (JP3) and one
jumper/connector on the Power Supply PCB (JP1). Jumper setting for both connectors is shown
in table 7-1.

Table 7-1. Voltage Selection Jumper Setting

VOLTAGE SELECTION CONNECTOR PIN

110/120 Vac Pin 1& 2, 3 & 4
220/240 Vac Pin 2 & 3

Note:

Operating voltage is set from the factory.

7.2 CT-7500 Main Power Fuse

The CT-7500 uses an AC input module containing the AC receptacle, Power switch, and
Protective fuse. Replacement fuse should be: 20mm, 2A-250Vac slow blow.

7.3 CT-7500 Printer and Printer Paper

The CT-7500 built-in thermal printer uses 4.5-inch wide thermal paper for printing test
results. To maintain the highest quality test-result printing and to avoid paper jamming, the use
of paper supplied by our factory is highly recommended. Additional paper can be ordered from
either of the two sources listed below:

Vanguard Instruments Co, Inc.

1710 Grevillea Court

Ontario, CA 91761
Tel: [phone]

Fax: [phone]

Part Number: TP-4 Paper

OR

BG Instrument Co.

13607 E. Trent Avenue

Spokane, WA 99216

Tel: [phone]

Fax: [phone]

Part Number: TP4 paper

7.4 CT-7500 Printer Paper Control

To advance paper from the printer, press and release the “↑ PAPER LCD” switch; to

retract the paper from the printer, press and release “↓ PAPER LCD” switch.

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7.5 Replacing CT-7500 Thermal Paper

The thermal paper roll is residing in the pocket under the printer cover. To replace the
thermal paper roll, follow these steps:



Remove printer cover.



Remove leftover thermal paper roll from paper holder.



Unroll new thermal paper roll.



Feed thermal paper into the slot between the paper pocket and roller.

The printer will pull paper under the thermal head.



Roll thermal paper roll and place this paper roll in paper holder.



Lift thermal head and align thermal paper if necessary.



Reinstall printer cover.

Note

Thermal paper will show a red stripe to indicate “Close to End of Paper”.

7.6 CT-7500 LCD Contrast Control

To Darken the LCD display, press and hold the “↑ PAPER LCD” switch for two seconds; to
lighten the LCD display, press and hold the “↓ PAPER LCD” switch for two seconds.

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8.0 TEST HOOKUP CONNECTIONS

8.1 Contact Cable Hookup

A typical contact cable connection to a circuit breaker is shown in Figure 8-1.

NOTE

It is advisable to ground one side of the contacts for most testing. If a breaker is floating
(i.e., ungrounded), ensure contact-channel inputs are protected against static discharge.

A typical series contact connection is shown in Figure 8-2.

8.2 Initiate Cable Hookup

A CT-7500 will trip or close breakers with a solid-state device, which will operate on any ac or
dc control voltage from 10 to 300 volts. Both the trip and close circuits are protected by 3-ampere
fuses.

A typical dc trip and dc close control circuit test hookup is shown in Figure 8-3.

A typical dc trip and ac close control circuit is shown in Figure 8-4.

8.3 Analog Voltage Monitor Hookup

The analog voltage input (V1) lets users monitor a breaker's dc-control voltage during
operation. The analog voltage input (V1) will record the norminal dc voltage (at no load) and the
minimum dc voltage (while the Trip or Close coil is energized).

Nominal and minimum voltage readings will print on a tabulated report. Analog waveform will
also plot in a graphic report. This lets the user see the breaker's dc control voltage "dip" under
load. Problems, such as a poor connection or an excessive voltage drop, during operation can
thus be easily detected.

A typical voltage monitoring hook up is shown on Figure 8.5.

NOTE

Maximum voltage recorded is 255 Vdc.

8.4 Digital Voltage Monitor Hookup

The Digital V2 voltage input channel lets users monitor the voltage ON/OFF state. The voltage
ON/OFF state will be plotted on the graphic report. A typical hook up is shown on Figure 8.5.

8.5 External Trigger Input

External trigger mode lets a user start a recording when the CT-7500 senses a voltage. A
typical application for this external trigger mode is to time a circuit breaker in a close operation and
to start timing only when the close coil is energized (bypassing the 52X relay delay time).
Since the 52X relay carries the close coil current, the user wants to connect the CT-7500’s initiate
cable to the close terminal (figure 8-4). The CT-7500 will energize the 52X relay to start the close
operation. The CT-7500 then will start the timing when it senses the voltage across the closing
coil. See Figure 8.6 for a typical test hookup.
Another application (for external trigger) is to start timing the breaker when the user trips or closes
the breaker remotely.

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NOTE

Minimum trigger voltage is set for 30 V ac/dc. Maximum continous voltage is 300Vac/dc.

Different trigger voltages can be set at the factory, based on specific requests from users.

The CT-7500 will start looking for the external trigger input voltage after the CT-7500 Initiate

Sequence is completed (CT-7500 stops beeping after the user presses “START” key) and

message “LOOKING FOR TRIGGER VOLTAGE” is shown on LCD.

This external trigger voltage needs to be sensed by the CT-7500 within 5 second after the

Initiate sequence. The CT-7500 will return to main menu if no voltage is sensed.

8.6 AC Current Sensor Hookup

A clamp-on AC current sensor connecting to the breaker bushing CT allows the CT-7500 to
sense breaker bushing current. The AC current sensor requires a 100mA current to operate.
Maximum current is 25 amperes. Typical hookup is shown on figure 8-8.

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Figure 8-1. Typical Single Break Contact Cable Hookup

Figure 8-2. Typical Series Contacts Test Cable Hookup

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Firgure 8-3. Typical DC Trip and Close Control Test Cable Hookup

Figure 8-4. Typical DC Trip and AC Close Control Test Cable Hookup

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Figure 8-5. Typical Voltage-Monitoring Test Cable Hookup

Figure 8-6. Typical External Trigger Hookup

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