Electrical Test Instruments MAC-20 User Manual

Electrical
Test lnstruments
MAC-20 Retrofit
Package
Section
lll
-
Operating
lnstructions
BASIC
GUIDELINES
AND SUGGESTIONS
1. Best timing
and current
accuracy will
be obtained
with the
MAC-20
in current
2.
'"tTrlt"i;'J,11";odes
are
prererred
for
most testins
purposer.
Er""ption.
"'",
a) Non-series-connected
devices such
as motor
overload
relays or shunt-trip
breakers.
b) Ratioing
of current transformers.
c) Heat
runs of cables, buswork,
etc.
(Connect
contacts
to thermostat).
d) Use
of MAC-20 as a
manually operated
timer.
3.
lf 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.
The MAC-20
may cause
a brief
initiation
when
power
is applied.
Although this
will not
normally affeci
testing,
it is important
to keep
in mind.
Therefore, set
the
output
Tap switch
and
Vernier to their
lowest
positions
before
energizing
the
test
set.
5.
Always choose
an
ammeter
range that
allows the
test current
to be
read
in
the
area
from 20o/o to
8O%o of the
maximum.
This
provides
greatest
accuracy
of read-
ings, least
chance
of overrange,
and optimum
current
latch
operation.
6.
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.
7.
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
out-
put
connections.
when using
tap
1, the vernier
control
should
always be
at least
at
30%
to
produce
desired test
current.
Electrical
Test lnstruments,
lnc.
Page
lll-3
Copyright(C)'1
994-1
998
All Rights
Reserved

Electrical Test Instruments MAC-20 Specifications

General

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