Description; Application - GE IAC66K Instructions Manual

The type IAC66K relay is similar to the IAC51B except:
to give a very l ong time operating characteristic, Fig. 1; (2) the tap ranges are shown in Table I, and (3 )
the relay has two instantaneous units, one standard unit, and one special high dropout unit.
is mounted in the front of the relay while the special unit is mounted in the rear.
are shown in Fig. 3 and the outline and panel drilling in Fig. 7.
The Type IAC66K relay is used for motor protection.
are shown in Fig. 4. The recommended settings for the three units are as follows:
Based on these settings, the ratings of the three units should be chosen as follows:
MOTOR FULL
LOAD CURRENT
0.8 -
1.4 - 2.6
l.B - 4.3
1.8 - 4.3
2.9 - 5.0
When adjusted as shown above, the relay operates as follows:
1. For overloads, the 51 unit times out, picking up external auxiliary 51X, which rings the alarm
bell.
2. For locked rotor, the 50/IOC-B unit will pick up instantaneously and the 51 unit will pick up
with time delay.
the motor.
3. For a fault, the 50/IOC-A unit will pick up instantaneously to trip the breaker and cause shut
down of the motor.
These instructions do not
every possible c ontingency to be met i n connection with installation,
further information be desired or should particular problems arise which are not covered s ufficiently
the purchaser's purposes,
To the extent required
but no such assurance is given with respect to local codes and ordinances because they vary greatly.
TIME OVERCURRENT RELAYS
T IME OVERCURRENT UNIT
NORMAL DROPOUT INST.
OVERCURRENT UN IT
H IGH DROPOUT INST.
O VERCURRENT UNIT
51 UNIT
1.7
l - 2
1.5- 3
2. 5 - 5
2 - 6
4 - 8
When both units have operated, the breaker is tripped to cause shut down of
cover
p o
urp rt to
the matter
should be referred to the General Electric Company.
the
products described herein meet applicable
GE I-44233
TYPE IAC66K
DESCR IPTION
(1) the U-magnet construction has been altered

APPLICATION

Typical external connections for motor protection
P.U. SETTING
MULTIPLES OF
UNIT FULL LOAD CUR.
1.15 to 1.4
51
50/IOC-A
50/IOC-B
RECOMMENDED RATINGS
50/ IOC-A
UNIT
10 - 40
10 - 40
20 - 80
20 - 80
20 - 80
all details or variations in
3
The s tandard
The internal connections
8 to 15
2 to 3
50/IOC-B
UNIT
2 - 6
4 - 12
4 - 12
4 - 12
4 - 12
equipment nor to provide
operation or maintenance.
ANSI,
NEMA
IEEE and
for
Should
for
standards;