Ground Fault Current Functions; Rtd Measurement Tests; Table 4-1 Rtd Resistance Vs. Temperature - GE MULTILIN 269 MOTOR MANAGEMENT RELAY Series Instruction Manual

4 RELAY TESTING
To simulate an overload condition turn "ACCEL.
TIME=" to "off" (SETPOINTS, page 1) and inject a cur-
rent of 9 Amps in all three phases. This will be read by
the relay as:
displayed current = 9 Amps × 100/5 = 180 Amps
which is two times the Full Load Current setpoint of 90
Amps. The trip output relay should activate after a time
of 116 seconds which is the time to trip for a 200%
overload using curve #4. This time may be less due to
the charging of thermal memory because of the pres-
ence of unbalance or previous overloads.
memory may be discharged to 0% by shorting together
the Emergency Restart terminals (54, 55) momentarily.
To check the displayed negative to positive sequence
unbalance ratio inject currents of 5.0 Amps, 5.0 Amps
and 3.9 Amps into the relay and examine the
"UNBALANCE RATIO". The reading should be 14%.
Other unbalance conditions can be checked by calcu-
lating the negative to positive sequence current ratio for
the injected phase currents and comparing this to the
ACTUAL VALUES display.

4.4 Ground Fault Current Functions

The ground fault current function uses digital current
information converted from the analog ground fault CT
input. The 269 relay must read the injected ground
fault current correctly in order for the ground fault func-
tion to operate properly. Using factory default setpoints
to test the ground fault input circuitry, pass a phase

Table 4-1 RTD Resistance vs. Temperature

TEMP
°C
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
4-4
Thermal
OHMS
OHMS
100 OHM Pt
120 OHM Ni
(DIN 43760)
100.00 120.00
103.90 127.17
107.79 134.52
111.67 142.06
115.54 149.79
119.39 157.74
123.24 165.90
127.07 174.25
130.89 182.84
134.70 191.64
138.50 200.64
142.29 209.85
146.06 219.29
149.82 228.96
153.58 238.85
157.32 248.95
161.04 259.30
164.76 269.91
168.47 280.77
172.46 291.96
175.84 303.46
current conductor through the ground fault CT window
as shown in figure 4-1.
should then be the same as the "GROUND FAULT
CURRENT" display in ACTUAL VALUES mode. If the
injected current is adjusted to over 4.0 Amps for longer
than 10.0 seconds the ground fault alarm should be-
come active. If over 8.0 Amps is injected for more than
50 msec. a ground fault trip should occur. These tests
can be performed for other CT ratios and setpoints.

4.5 RTD Measurement Tests

The correct operation of each of the RTD inputs can be
tested by simulating RTDs with potentiometers. To test
a 269 relay configured for use with 100 OHM platinum
RTDs, 100 OHM potentiometers and resistors can be
used. These should be connected to each RTD as
shown in figure 4-1.
Table 4-1 shows RTD resistances for various tempera-
tures. Individual, actual stator and bearing RTD tem-
peratures can be viewed in ACTUAL VALUES mode,
page 2.
To test overtemperature trip/alarm functions the simu-
lated RTD potentiometers should be adjusted to corre-
spond to high RTD temperatures.
Stator RTD Voting in Setpoint Values page 5 should be
defeated first. This allows for individual trip/alarm over-
temperature testing.
OHMS
100 OHM Ni 10 OHM Cu
100.00
105.97
112.10
118.38
124.82
131.45
138.25
145.20
152.37
159.70
167.20
174.87
182.75
190.80
199.04
207.45
216.08
224.92
233.97
243.30
252.88
The actual injected current
OHMS
9.04
9.42
9.81
10.19
10.58
10.97
11.35
11.74
12.12
12.51
12.90
13.28
13.67
14.06
14.44
14.83
15.22
15.61
16.00
16.39
16.78