Electrical Test lnstruments MAC-20 Retrofit
Package
Section Ill
-
Operating lnstructions
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 COrufnOl
higher, until the desired test current is read
on the ammeter.
lf
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.
3. Press RESET button.
4.
Set TIMEBASE to SECONDS.
5. Select LATCH mode.
6. lf desired, N.C. mode may
be used; connect contacts leads to an unused
pole
of
the breaker.
7. Press and release INITIATE key;
CLOSE or 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, CLOSE or
OUTPUT ON
light
should
turn off, and TRIP or OUTPUT OFF light should
glow
(lf
applicable).
9.
Read
and
record
trip current and trip time. Compare to manufacturefs time/current
curve.
lf necessary,
adjust the trip unit and repeat the test.
10. 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.
1 1. Shut down test set, disconnect breaker, and
prepare
for subsequent testing or
relocation according to steps 20 through 25 in
general procedures
outlined
above.
Pick-Up of the lnstantaneous Unit
1. Consult breaker
manufacturer's literature
to
determine
any
necessary
precautions
and
expected test results. Note: lf the instantaneous setting is such that the ex-
pected
test result is above that which may be easily
produced
by the test set, a
valid test may be
performed
by adjusting the setting to its minimum value. At the
end of the test,
restore the instantaneous setting to its specified value,
2. Follow steps 1 through
18 in
general
test
procedures,
as required, to set up the
breaker test set.
3.
Setup MAC-20
for C.L. MOM.
4. Set
MAC-20 RANGE to lowest
range that is
greater
than desired test current.
5. Set TIMEBASE
to CYCLES.
\_
6.
Press PRESET key.
Adjust
preset
time to 6.0 cycles.
(This
value may be set higher
Electrical
Test lnstruments, lnc.
Page lll12
Copyright(C)
1 994-1998
All Rights Reserved
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