Electrical Test Instruments PI-6000
Section IV - Operating Instructions
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Copyright(C) 1994-2019 Electrical Test Instruments, LLC All Rights Reserved
Page IV-2
BASIC GUIDELINES AND SUGGESTIONS
1.
Best timing and current accuracy will be obtained with the MAC-21 in
current 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
sensing cables. Although the voltage and current are minimal, under some
conditions 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
operation.
5.
To obtain maximum output current from the test set, especially when
using output cables, it is important to minimize both input and output
impedance. This can be accomplished by using the largest cable size
possible, or using multiple cables in parallel, to reduce resistance, and by
keeping cables 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
positions. 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 rheostat control should always be at least at 30% to produce desired
test current.
