Characteristics; Operating Prrnciples; Pickup; Operating And Reset Times - GE ICW51A Instructions Manual

CHARACTERISTICS
OPERA TING PRINCIPLES
The induction disk unit of the ICW relays
covered by these instructions is similar in operating
principles to the familiar watthour-meter unit.
Operating torque results from the interaction of the
magnetic fluxes produced by the current coil (upper)
and potential coils (lower). Maximum operating
torque occurs when the operating current at the
relay terminals leads the polarizing voltage by 90
degrees. Consequently
if
quadrature polarizing
voltage is used (see APPLICATION) maximum torque
will
occur when the power system line current is at
unity power factor.
PICKUP
Power Relays Type ICW GEH-2056
to tap setting with rated voltage on the potential
circuit are shown in Fig. 2. Pickup and reset time
curves for the Type ICW52A over-and under-power
relay in terms of percent of the power required to
close the left contact with rated voltage on the
potential circuit are shown in Fig. 3.
Dropout time for the ICW51A and ICW52B
relays, i.e. time to reopen the left contact when the
relay is deenergized, is approximately 0.05 secs.
Reset time, i.e. the time required for the contact
and shaft assembly to reset against the stop, will of
Course depend upon the time dial setting.
It
is
apprOximately 22 seconds for the No. 10 time dial
setting and will be proportionately lower for lower
time dial settings.
BURDEN
The relays can be set to pick up, i.e. close the
left hand contact, at the 3-phase secondary watts
listed in Table A (RATINGS). Pickup will be within
± 5 percent of the tap value selected. Closer ad-
justment of pickup watts, or adjustment for a pickup
pOint between tap pOSitions, can be obtained by ad-
justing the lower control spring as described under
INSTALLATION PROCEDURE. The relays will
drop out, i.e. open the left hand contact, at approxi-
mately 96 percent of the pickup setting.
*
Potential Burden at Rated Voltage:
RATED
Volts
Freq.
Watts Vars
Volt-amp P.F.
120 60 4.62
1.01 4.73 0.98
208
60 7.43 1.09 7.51 0.99
240 60 9.80
2.00 10.0 0.98
480 60 61.3
6.1 61.6 0.99
120 50 4.38
0.66 4.43 0.99
OPERATING AND RESET TIMES
208 50 5.12 0.79
5.18 0.99
PiCkup time curves for the Types ICW51A and
*
The burdens imposed on the current transformer
ICW52B overpower relays as a function of multiples are shown in Table D.
*
TABLE D
RATINGS
""BURDEN AT BURDEN IN OHMS
MINIMUM PICKUP
IMPEDANCE AT:
RANGE
V
Freq.
R X Z 5 Amp 10 Amp 20 Amp 40 Amp
10-40
120 60 2.08 6.4 6.7 5.70 3.82
Z.HH
2.34
15-60
120
60 0.92 2.8
2.9 2.80
2.70 1.40 1.10
26-104
208
15-60 120 50 0.80 2.3 2.4
2.32 1.74 1.16 0.91
20-80 120 60 0.52 1.6 1.7 1.70 1.44 0.97 0.73
25-100 120
44-175 208
60 0.33 1.0 1.04 1.04
0.96 0.68 0.47
100-400
480
25-100
120
50 0.30
0.80 0.85 0.85 0.79 0.55 0.39
50-200
208
60 0.25 0.75
0.78 0.78 0.76 0.55
0.~7
~0-2DO
20H
50
0.21 0.62 0.65 0.65
~ti4 0.46 O.~l
50-200
120
87-350
208
60 0.08 0.25 0.26 0.26
0.26 0.24 0.17
100-400 240
50-200 120
50
0.07 0.21
0.22 0~2 0.22 0.20 0.14
100-400
120
60 0.02 0.063 0.07 0.07 0.07 0.07 0.06
175-700
208
200-800 120
350-1400 208
60
0.005
0.016 0.017 0.017 0.017 0.017 0.017
200-800
120
50 0.004 0.013
0.014
0.014 0.014 0.014
0.014
100-1000 120 60
0.23 0.70 074 0.74 0.74 0.53 0.36
100-1000
120 50 0.20 0.58 060 0.60
~§O ~U -.!L~
**
The values given are those for the minimum tap of each relay. The values for other taps at
pickup (Tap Rating) varies approximately inversely as the square of the tap rating. Burdens
are on the basis of the pickup current with rated voltage applied to the potential circuit.
·Indicates revision
5