GE 239, Instruction Manual

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8-2 239 Motor Protection Relay GE Multilin
8 TESTING 8 TESTING
8
8.3 PHASE CURRENT ACCURACY
Any phase current protection is based on the ability of the 239 to read phase input currents accu-
rately to ±2% of full scale. Perform the steps below to test the phase current accuracy.
1. Alter the following setpoint.
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2. To determine if the relay is reading the proper input current values, inject phase currents shown
in the table below, view the readings in
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, and verify with the expected read-
ings stated in the table.
3. Alter the setup to inject current into the 1 A input of each phase and repeat the above step with
current settings shown in the table below.
Table 8–1: PHASE CURRENT ACCURACY TEST, 5 A INPUT
INJECTED
CURRENT EXPECTED
READING IN EACH
PHASE †
ACTUAL PHASE
A READING (A)
ACTUAL PHASE
B READING (A)
ACTUAL PHASE
C READING (A)
0.5 A 10 A
1.0 A 20 A
3.5 A 70 A
5.0 A 100 A
10.0 A 200 A
†
Table 8–2: PHASE CURRENT ACCURACY TEST, 1 A INPUT
INJECTED
CURRENT EXPECTED
READING IN EACH
PHASE †
ACTUAL PHASE
A READING (A)
ACTUAL PHASE
B READING (A)
ACTUAL PHASE
C READING (A)
0.1 A 10 A
0.3 A 30 A
0.6 A 60 A
1.0 A 100 A
2.0 A 200 A
†
displayed current injected current
PHASE CT PRIMARY
5 A
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 
 
×
=
displayed current injected current PHASE CT PRIMARY
×
=