Electrical Test Instruments PI-6000
Section IV - Operating Instructions
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Page IV-10
19.
Repeat the above tests for the other poles of the breaker, allowing time for
breaker to cool. Note: Results are acceptable if all poles of the breaker trip
within the manufacturer's time range for the value of test current chosen.
All poles of the breaker need not trip in exactly the same amount of time.
20.
Shut down test set, disconnect breaker, and prepare for subsequent
testing or relocation according to steps 18 through 22 in pre-test
installation and setup outlined above.
Timing Test, Short Time Delay
Note: The breaker's trip time for short time delay will always be less than 30
cycles and may be as low as 4-5 cycles. Therefore, setting test current will
require some practice. However, the magnitude of the test current is not
critical; for instance, if the S.T.D. is set for 1000 amperes, there will be little or no
difference in timing if a test current of 1500, 2000 or 2500 amperes is used.
Set up of controls is the same as for timing test L.T.D. Consult breaker
manufacturer's literature to determine any necessary precautions and
expected test results.
1.
Follow steps 1 through 8 under Timing Test Long Time Delay.
2.
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 rheostat, set
the OUTPUT TAP control to the next higher tap, return the rheostat to zero,
and continue.
3.
Press RESET button.
4.
Set TIMEBASE to SECONDS.
5.
Select MAINTAIN mode.
6.
If desired, N.C. mode may be used; connect contacts leads to an unused
pole of the breaker.
7.
Press and release INITIATE key; OUTPUT ON light should glow, timer
should run, and current display should read desired output current.
8.
Breaker should trip within 30 cycles (0.5 seconds). When breaker trips, the
test set output should de-energize, timer should stop, OUTPUT ON light
should turn off.
9.
Read and record trip current and trip time. Compare to manufacturer's
time/current curve. If necessary, adjust the trip unit and repeat the test.
