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-5
BASIC GUIDELINES AND SUGGESTIONS
1.
Best timing and current accuracy will be obtained with the MAC-21 in cur-
rent latch (C.L.) mode.
2.
Current Latch modes are preferred for most testing purposes. Exceptions
are:
a)
Non-series-connected devices such as motor overload relays or shunt-
trip breakers.
b)
Ratioing of current transformers.
c)
Heat runs of cables, bus work, etc. (Connect contacts to thermostat).
3.
If Contacts Mode is selected, use caution when connecting continuity sens-
ing cables. Although the voltage and current are minimal, under some con-
ditions it could cause electrical shock. ALWAYS connect one clip at a time,
and NEVER rest the other hand on any current-carrying parts of the
breaker while the test set is powered up.
4.
Always choose an ammeter range that allows the test current to be read in
the area from 20% to 80% of the maximum. This provides greatest accuracy
of readings, least chance of overrange, and optimum current latch opera-
tion.
5.
To obtain maximum output current from the test set, especially when us-
ing output cables, it is important to minimize both input and output im-
pedance. This can be accomplished by using the largest cable size possible,
or using multiple cables in parallel, to reduce resistance, and by keeping ca-
bles close together by tying or twisting, to reduce inductance.
6.
For all breaker test sets, much better output current waveform and stability
can be achieved when the controls of the test set are in their higher posi-
tions. To test smaller breakers, it is helpful to introduce additional output
impedance, by using some length of adequate, but lighter gauge, wire to
connect the breaker to the output connections. When using tap 1, the Ver-
nier control should always be at least at 30% to produce desired test cur-
rent.
