GE IAV51A Instructions Manual page 4

GEH-1814 Voltage Relays Type IAV
The IAV51K relay is similar to the IAV51D
except that it has an external capacitor.
The lA V52A relay is similar in every respect
to the lA V51A relay except that it has additional
contacts for closing a second circuit.
The lA V53A relay is an under-and overvoltage
relay with double-throw contacts.
contacts close the voltage increases to some
as
predetermined value. The right-hand contacts close
when the voltage decreases to some lower value.
Between these two voltage values both contacts are
open. Time-voltage characteristics are shown in
Fig. 2.
The Type lA V53B relay differs from the Type
IAV53A relay in that it does not have seal-in ele­
ments. Time-voltage characteristics are shown in
Fig. 2.
The Type lA V53C relay is similar to the Type
lA V53A relay except that there are no taps on the
coil. The relay is adjusted to close its right con­
tacts in 10 seconds when the voltage is reduced
from 58% rated voltage to zero voltage; with this
calibration the relay closes its left contacts in ap­
proximately 10 seconds when the voltage is in­
creased from 58% of rated voltage to rated voltage.
These relays are used connected line-to-ground so
that under normal conditions the relay receives 58%
of rated phase-to-phase voltage and both relay con­
If the phase to which the relay is
tacts are open.
connected is grounded, the relay voltage goes to
zero and the right-hand contacts close in 10 seconds.
If either of the other two phases are grounded, the
relay voltage increases to rated voltage and the
left-hand contacts close in approximately 10 seconds.
The lA V53D relay is similar to the Type lA V-
53B relay except that it has a shorter time curve.
Time-voltage characteristics are shown in Fig. 4.
RATINGS
The operating circuit ratings available are 115
or 230 volts at 60, 50 or 25 cycles. The operating
coil will stand rated voltage continuously on any
tap and will stand tap voltage continuously on the
taps above rated voltage.
The current closing rating of the contacts . is
30 amperes for voltages not exceeding 250 volts.
The current-carrying ratings are affected by the
selection of the tap on the seal-in coil as indicated
in the following table.
4
Function
Tripping Duty
Carry Continuously
The left-hand
The 2-ampere tap
ohms and a 60 cycle impedance of 0.53 ohms while
the 0.2-ampere tap has a
a 52 ohm 60 cycle impedance. The tap setting used
on the seal-in element is determined by the current
drawn by the trip coil.
The 0.2-ampere tap is for use with trip coils
that operate on currents ranging from 0.2 up to 2.0
amperes at the minimum control voltage. If this tap
is used with trip coils requiring more than 2 am­
peres, there is a possibility that the
will reduce the current to so low a value that the
breaker will not be tripped.
The 2-ampere tap should be used with trip coils
that take 2 amperes or more at minimum control
voltage, provided the tripping current does not ex­
ceed 30 amperes at the maximum control voltage. If
the tripping current exceeds 30 amperes an auxiliary
relay should be used, the connections being such
that the tripping current does not pass through the
contacts of the target and seal-in coil of the pro­
tective relay.
. The above data in regard to contact rating ap­
plies to all relays covered by these instructions
except the Types lA V53B and IAV53C which do not
have seal-in units. In these cases, the contact rat­
ings are limited in their current-carrying capacity
by the interrupting ratings as shown below:
Function
Make and
Interrupt
at
* Noninductive Load
Amperes
0.2-Amp Tap
2-Amp Tap
3
30
0.3
3
a d-e resistance of 0.13
has
ohm d-e resistance and
7
-ohm resistance
7
Amperes
Volts
AC
125 1.5
250 0.75
600 0.00
DC
0.3*
0.15*
0.00