Electrical Test Instruments MAC-20 User Manual

Electrical
Test lnstruments
MAC-20
Retrofit
package
Section
lV
-
Service
lnformation
and Documentation
6. set
MAC-20
Range
to 1 000
A,
and adjust
output
of breaker
test
set to exacily
g00
Amperes.
lf
Coarse Tap
is 1,
and
Output
Control Vernier
is less
than
50%, addi_
tional
resistance
must
be added
to output
circuit.
This is
important,
because
wave-
form
distortion
is more
prevalent
at
lower levels.
7. lf the
MAC-20
reading
differs
from
the
standard
by more
than rateil
accuracy,
adjust the
gain potentiometer
on the
analog
board for
proper
reading.
lf an
error
of
more
than 5%
is noted,
and
unit has
been
in service,
the accuracy
and
validity
of
previous
tests
may be
questionable;
otherwise,
there
may
be a
problem
in
the test
setup.
8.
Check calibration
at 200,
400,
600,
and 1000
Amperes.
9.
Adjust
the current
to zero,
and
press
RESET
key.
10. Raise
the
current
slowly,
until the
timer
begins
to run. This
is
the current
Latch
Threshold,
which
should
be
about
5% of full
scale range.
11.
Set the current
at 50% of
full scale
(500
A), and
stop the
current.
12.
Set the
MAC-20
to MEMORY
mode,
and
press
the
RESET
Switch.
13. lnitiate
a fast
momentary
pulse
of no more
than
6 cycles
(0.1
sec) duration.
The
meter
should
read
the
same value,
within
2%,
that was
set in
step 11
above.
14.
Check
pulse
reading
operation
in this
manner for
currents
of
200, 400,600,
and
1000
Amperes,
and varying
duration.
15.
set Timer
Timebase
to
SECoNDS.
Press
Master
Reset
Switch.
set N.o.
mode.
using
a stopwatch,
initiate
for
exacily
ninety
(90)
seconds. Timer
should
read
g0.00
seconds,
+/-
0.0'1
seconds.
(Note:
actual reading
may
vary
because
of inability
to
control and
measure
pulse
length.)
16. lf
everything
checks
out,
the MAc-20
can be
assumed
to be in
calibration,
and
no
other
adjustments
are required.
Electrical Test lnstruments,
lnc.
Page lV-2
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1 994-1 998
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Reserved

Electrical Test Instruments MAC-20 Specifications

General

Brand	Electrical Test Instruments
Model	MAC-20
Category	Controller
Language	English