MCCB-250 MOLDED-CASE CIRCUIT BREAKER TESTER USER’S MANUAL Vanguard Instruments Company, Inc. 1520 S. Hellman Ave.
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.
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 ......................................................................
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 2. OPTION 3. OPTION 4.
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.
MCCB-250 USER’S MANUAL 1.3 REV 2 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.
REV 2 MCCB-250 USER’S MANUAL 1.4 Controls and Indicators The MCCB-250’s controls and indicators are shown in Figure 1. A leader line with an index number points to each control and indicator, which is cross-referenced to a functional description in Table 2. The table describes the function of each item on the control panel. The purpose of the controls and indicators may seem obvious, but users should become familiar with them before using the MCCB-250.
MCCB-250 USER’S MANUAL REV 2 Table 2. Functional Descriptions of MCCB-250 Controls and Indicators Item Number Panel Markings 1 COM Current source common terminal. 2 250A 250A current source terminal. 3 120A 120A current source terminal. 4 25A 25A current source terminal. 5 5A Functional Description 5A current source terminal RS-232C (serial) interface port for factory firmware programming and diagnostics.
REV 2 MCCB-250 USER’S MANUAL 2.0 FUNCTIONAL DESCRIPTION 2.1 MCCB-250 AC Current Source The MCCB-250 provides five AC current outputs (items 1, 2, 3, 4, and 5 in Figure 1). AC test current is set by the [CURRENT CONTROL] knob. This test current is measured and displayed on the LCD screen. The MCCB-250’s output current ratings are shown in Table 3 and Table 4 below. Table 3. MCCB-250 Current Output CURRENT OUTPUT 120 Vac @ 5A 24 Vac @ 25A 6 Vac @ 120A 3 Vac @ 250A Table 4.
MCCB-250 USER’S MANUAL 2.2 REV 2 MCCB-250 Current Output Control The MCCB-250 current source output is controlled by the [UP ARROW] and [DOWN ARROW] keys (item 13 in Figure 1). Three control modes are available: ON+TMR, OFF, and MOMT. The OFF mode indicates that both the current source output and timer are off. The MOMT mode turns on the current source momentarily. To turn on the current source, press and hold the [DOWN ARROW] key.
REV 2 2.3 MCCB-250 USER’S MANUAL Timer Stop Input and Control After a test is started, the MCCB-250 timer can be stopped and the current source turned off using one of three modes: dry contact input, wet contact input, or interruption of the MCCB-250 current output. The [LEFT ARROW] key is used to select the desired mode. When the DRY CONTACT mode is selected, the MCCB250 will output a DC voltage to the [TIMER STOP] terminals to sense the state of the dry contacts.
MCCB-250 USER’S MANUAL 2.4 REV 2 MCCB-250 Timer The MCCB-250’s built-in time/cycle counter can be used to time events in milliseconds and cycles. The elapsed time is displayed on the LCD screen along with the test current after a test is completed. A typical test results screen is shown in Figure 2. The timer is turned on when the ON+TMR mode is selected. Figure 2. Typical MCCB-250 Test Results Screen 2.
REV 2 MCCB-250 USER’S MANUAL 3.0 OPERATING PROCEDURES 3.1 Testing the Time Delay of a Protection Relay Figure 3 illustrates a typical connection of the MCCB-250 to a protection relay to test its “Open Time Delay”. The MCCB-250 injects a test current through a bus. The test current is sensed by the CT of the protection relay. One of the relay dry contacts is used to stop the MCCB-250 timer. Figure 3.
MCCB-250 USER’S MANUAL REV 2 Use the steps below to test the time delay of a protection relay: a. Connect the Safety Ground to the MCCB-250. b. Connect the AC power cord. c. Connect the Current Cables from the MCCB-250 to the bus as shown in Figure 3. d. Connect the [TIMER STOP] cables as shown in Figure 3. e. Turn the [CURRENT CONTROL] knob to zero. f. Turn on the [POWER SWITCH]. g.
REV 2 3.2 MCCB-250 USER’S MANUAL Measuring Current Transformer Primary and Secondary Currents Figure 4 shows a typical connection of the MCCB-250 to a current transformer. In this configuration, the MCCB-250 injects a test current through the CT primary. The CT secondary current is sensed by the MCCB-250’s [EXT CURRENT] input. Figure 4.
MCCB-250 USER’S MANUAL REV 2 Follow the steps below to measure the CT primary and secondary currents: a. Connect the Safety Ground to the MCCB-250. b. Connect the Current cables from the MCCB-250 to the bus (CT primary) as shown in Figure 4. c. Connect the CT secondary winding to the MCCB-250 [EXT CURRENT] input as shown in Figure 4. d. Turn the [CURRENT CONTROL] knob to zero. e. Turn on the [POWER SWITCH]. f. Hold the [DOWN ARROW] key to momentarily turn on the current source. g.
1520 S. Hellman Ave • Ontario, CA 91761 • USA Phone: 909-923-9390 • Fax: 909-923-9391 www.vanguard-instruments.com Copyright © 2009 by Vanguard Instruments Company, Inc.
