Vanguard MCCB-250 User Manual

MCCB-250

MOLDED-CASE CIRCUIT BREAKER TESTER

USER’S MANUAL

Vanguard Instruments Company, Inc.

1520 S. Hellman Ave.
Ontario, California 91761, USA

TEL: [phone]
FAX: [phone]

September 2009

Revision 2

MCCB-250 USER’S MANUAL REV 2

SAFETY SUMMARY

FOLLOW EXACT OPERATING PROCEDURES

Any deviation from the procedures described in this User’s Manual may create one or more
safety hazards, may damage the MCCB-250, or cause errors in the test results. Vanguard
Instruments Company, Inc. assumes no liability for unsafe or improper use of the MCCB-250.

All safety precautions provided in this manual must be observed during all phases of testing
including test preparation, test lead connection, actual testing, and test lead disconnection.

SAFETY WARNINGS AND CAUTIONS

Only trained operators shall use this device. All circuits under test shall be off-line and fully
isolated.

DO NOT MODIFY TEST EQUIPMENT

To avoid the risk of introducing additional or unknown hazards, do not install substitute parts or
perform any unauthorized modification to any MCCB-250 test unit. To ensure that all designed
safety features are maintained, it is highly recommended that repairs be performed only by
Vanguard Instruments Company factory personnel or by an authorized repair service provider.
Unauthorized modifications can cause safety hazards and will void the manufacturer’s
warranty.

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REV 2 MCCB-250 USER’S MANUAL

TABLE OF CONTENTS

CONVENTIONS USED IN THIS DOCUMENT ....................................................................... 1

1.0 INTRODUCTION .................................................................................................................. .. 2

1.1 General Description and Features ................................................................................... 2

1.2 Furnished Accessories ...................................................................................................... 2

1.3 MCCB-250 Technical Specifications ................................................................................. 3

1.4 Controls and Indicators .................................................................................................... 4

2.0 FUNCTIONAL DESCRIPTION ................................................................................................. 6

2.1 MCCB-250 AC Current Source .......................................................................................... 6

2.2 MCCB-250 Current Output Control ................................................................................. 7

2.3 Timer Stop Input and Control .......................................................................................... 8

2.4 MCCB-250 Timer .............................................................................................................. 9

2.5 External Current Input ..................................................................................................... 9

2.6 LCD Contrast Control ....................................................................................................... 9

3.0 OPERATING PROCEDURES ................................................................................................. 10

3.1 Testing the Time Delay of a Protection Relay ................................................................ 10

3.2 Measuring Current Transformer Primary and Secondary Currents .............................. 12

LIST OF TABLES

Table 1. MCCB-250 Technical Specifications .................................................................................. 3

Table 2. Functional Descriptions of MCCB-250 Controls and Indicators ........................................ 5

Table 3. MCCB-250 Current Output ................................................................................................ 6

Table 4. MCCB-250 Overload Current Output ................................................................................ 6

LIST OF FIGURES

Figure 1. MCCB-250 Controls and Indicators .................................................................................. 4

Figure 2. Typical MCCB-250 Test Results Screen ............................................................................ 9

Figure 3. Typical MCCB-250 Application ....................................................................................... 10

Figure 4. Typical Current Transformer Current Ratio Test Connections ...................................... 12

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MCCB-250 USER’S MANUAL REV 2

CONVENTIONS USED IN THIS DOCUMENT

This document uses the following conventions:

• A key, switch, input, or knob on the MCCB-250 is indicated as [KEY], [SWITCH],

[INPUT], [KNOB]

Menu options are referenced as (MENU OPTION).

•

• MCCB-250 LCD screen output is shown as:

1. OPTION 1

2. OPTION 2

3. OPTION 3

4. OPTION 4

• Warning messages are indicated as:

WARNING

.

Warning message

• Important notes are indicated as:

Note details

NOTE

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REV 2 MCCB-250 USER’S MANUAL

1.0 INTRODUCTION

1.1 General Description and Features

The MCCB-250 is a programmable, high-current source designed specifically for testing molded­case circuit breakers as well as thermal, magnetic, or solid-state overload motor-protection
relays.

MCCB-250 Timer

The MCCB-250’s built-in timer can test the time-delay characteristics of protection relays and
molded-case circuit breakers. Once the test is initiated, the current source and the timer are
automatically turned on at the next zero-crossing point of the AC. The timer stops when the
MCCB-250 input detects a change in the dry contact or voltage input, or detects the removal of
the test current. The test results are then displayed in milliseconds and fractions of a cycle(s) on
the unit’s back-lit LCD screen (20 characters by 4 lines).

MCCB-250 Current Source

The MCCB-250 has 4 current-source outputs (5 A @ 120 Vac, 25 A @ 24 Vac, 120 A @ 6 Vac,
250 A @ 3 Vac) that conduct the test current through the high-impedance load circuits. Each
current source can tolerate short-duration over-loads up to 4 times the rated current. This
feature is used for testing the instantaneous trip element of molded-case circuit breakers.
When using this feature, the selected test current is displayed on the LCD screen. When the
MCCB-250 is used as a current source, the current-flow time (the current-on period) is
displayed on the LCD screen.

External Current Input

The MCCB-250 also provides an external current input (0 – 10 A). Both internal and external
current source readings can be viewed at the same time.

1.2 Furnished Accessories

The MCCB-250 comes furnished with the following:

• Two 10-foot #4 AWG current cables with heavy-duty alligator clamps

• One 10-foot #10 AWG current cable

• Two 10-foot external current input cables with alligator clips

• Two 10-foot external timer input cables with alligator clips.

• One ground cable

• One power cord

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1.3 MCCB-250 Technical Specifications

Table 1. MCCB-250 Technical Specifications

TYPE 250 Ampere current source

PHYSICAL SPECIFICATIONS Dimensions: 16.8”W x 12.6”H x 10.6”D (42.6 cm x 32.0 cm x 27.0 cm);

Weight: 46 lbs (21 kg)

INPUT POWER 100 – 120 Vac or 200 – 240 Vac (factory pre-set), 50/60 Hz

OUTPUT CURRENTS 0 – 5 A @ 120 Vac max; 0 – 25 A @ 24 Vac max;

0 – 120 A @ 6 Vac max; 0 – 250 A @ 3 Vac max

INTERNAL CURRENT METER 100 mA – 1000 A; Accuracy: 1% of reading ±20mA

MEASUREMENT METHOD Isolated CT

EXTERNAL METER RANGE 10 mA – 10 A; Accuracy: 1% of reading, ±2mA

MEASUREMENT METHOD Isolated CT

TIMER READING RANGE 1ms – 2 hours; Accuracy: 0.1% of reading ±1ms

TIMER STOP INPUTS Voltage input (24V – 300V, DC or peak AC), dry contact input, or removal

of primary current

DISPLAY Back-lit LCD Screen (20 characters by 4 lines); viewable in bright sunlight

and low-light levels

COMPUTER INTERFACE RS-232C port for factory calibration and diagnostics

SAFETY Designed to meet IEC61010 (1995), UL61010A-1, CSA-C22.2 standards

ENVIRONMENT Operating: -10˚C to 50˚ C (15˚F to +122˚ F); Storage: -30˚ C to 70˚ C (-

22˚F to +158˚ F)

CABLES Power cord, ground cable, two 10-foot (#4 AWG) test leads, one 10-foot

(#10 AWG) test lead , four 10-foot external input cables

OPTIONS Transportation case

WARRANTY One year on parts and labor

MCCB-250 USER’S MANUAL REV 2

The above specifications are valid at nominal operating voltage and at a
temperature of 25°C (77°F). Specifications may change without prior notice.

NOTE

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