Electrical Test Instruments PI-2500-G2 and PI-5000-G2
Section V - Service Information and Documentation
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Copyright(C) 1994-2021 Electrical Test Instruments, LLC. All Rights Reserved
Page IV-9
MULTI-POLE MOLDED CASE CIRCUIT BREAKERS
Timing Test
1.
Consult breaker manufacturer's literature to determine any necessary pre-
cautions and expected test results. A test current of three times the rating
of the breaker should be used for this test.
2.
Follow steps 1 through 16 in pre-test installation and setup, as required, to
set up the breaker test set.
3.
Connect appropriate output tap to one pole of breaker under test.
4.
Setup MAC-21 for C.L. Maint (MAINTAIN on).
5.
Set MAC-21 RANGE to lowest range that is greater than desired test cur-
rent.
6.
Set TIMEBASE to CYCLES.
7.
Press PRESET key. Adjust preset time to 5.0 cycles. This value may be set
higher or lower, depending on trip characteristics of breaker.
8.
Press PRESET again to return to normal mode.
9.
Select MEMORY mode.
10.
Repeatedly jog the INITIATE button, while adjusting the OUTPUT
CONTROL higher, until the desired test current is read on the ammeter. If
insufficient current is obtained at maximum position of the Vernier, set the
OUTPUT TAP control to the next higher tap, return the Vernier to zero, and
continue.
11.
Press RESET button.
12.
Set TIMEBASE to SECONDS.
13.
Select MAINTAIN mode.
14.
If desired, N.C. mode may be used; connect contacts leads to an unused
pole of the breaker.
15.
Press and release INITIATE key; OUTPUT ON light should glow, timer
should run, and current display should read desired output current.
16.
While test is running, observe current reading. If necessary, adjust to cor-
rect value by using Vernier control.
17.
When breaker trips, the test set output should de-energize, timer should
stop, and OUTPUT ON light should turn off.
18.
Read and record trip current and trip time. Compare to manufacturer's
time/current curve.
19.
Repeat above tests for other poles of the breaker. Allow time for breaker to
cool. Note: it is acceptable if all poles of the breaker trip /- 15% of the
