GEK-86105
TYPE IAC66M
TIME OVERCURRENT RELAY
DESCRIPTION
Type IAC66N relays contain a long time induction overcurrent unit, a standard
instantaneous unit, a high dropout instantaneous overcurrent unit, a six-cycle time
delay telephone relay, and two target and seal-in units.
See Figures
1
and
2
for
the location of these units, and Figure
3
for outline and panel drilling dimensions.
APPLICATION
The IAC66M relay was designed for motor overload and fault current protection.
The
induction
overcurrent
unit
provides
overload
protection
and
should
be
set
accordingly,
depending
on the service
factor of the machine.
The standard
instantaneous unit should be set above the maximum asymmetrical motor inrush
current.
The six-cycle time delay telephone relay used in conjunction with the high
dropout instantaneous unit permits it to override the transient asymmetrical motor
inrush current.
One of the target seal-in units is for use with the induction unit,
and the other is for use with the high dropout instantaneous unit.
The typical
external connection diagram is shown in Figure
5.
RATINGS
INDUCTION UNIT
The induction unit coil is available in several ranges of pickup current.
Table
I
lists ranges, tap values, continuous-current ratings and short time current ratings
of the
induction unit coil.
The induction unit contacts will close
30
amperes for voltages not exceeding
250
volts.
The current carrying ratings are affected by the tap selected on the target
and seal-in coil, as indicated in Table
II.
I
f the tripping current exceeds
30
amperes, use an auxiliary relay that is connected such that the tripping current
does not pass through either the contacts or the target and seal-in coils of the
protective relay.
These instructions do
not purport
to cover
all details or varidtions
in
equi
p
ment
nor to provide for
every
possible
contingency to be met
in co
n
n
e
ct
i
o
n
with
installation,
operation or
�intenance.
Should
furthe�
1nformation be desired or should particular problems arise
which are
not
covered
.sufficiently tor
the
purchdser's purposes, the �tter should be referred
to the
General
Electric
Compan�.
To the extent required
the
products described herein
meet applicable
ANSI,
IEEE and NEMA
standards;
but
no
such assurance is given
with
respect to
local
codes and
ordinances because
they vary
greatl�.
3
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