Phase Current Overload; Phase Unbalance Alarm - GE 239 Instruction Manual

8 TESTING
1. Alter the following setpoints:
6 3527(&7,21?3+$6( &855(17?29(5/2$'?29(5/2$' &859( 180%(5 
6 6<67(0 6(783?&7 ,13876?3+$6( &7 35,0$5< $
6 6<67(0 6(783?02725 '$7$?02725 )8// /2$' &855(17 $
6 7(67,1*?7(67 &21),*85$7,21?',6$%/( 67$57 3527(&7,21 <(6
2. Before beginning this test it is necessary to ensure that the thermal capacity value in $ 0(7(5
,1*?02725 &$3$&,7< is 0% to obtain a proper trip time. If required reset this value to 0% by short-
ing together the Emergency Restart switch terminals (39, 44) momentarily. The Emergency
Restart input will not function if any phase or ground current is injected.
3. Inject a current of 10 A into each phase in series. The relay will display a current value of:
displayed current
This represents four times 6 6<67(0 6(783?02725 '$7$?02725 )8// /2$' &855(17 setpoint.
Therefore, based on a 400% overload and curve #4, the trip relay should activate after a time of
23.3 seconds after the overload is first applied.
4. After the overload trip has occurred, verify by viewing $ 0(7(5,1*?02725 &$3$&,7< that the ther-
mal capacity used is 98% to 100%. The thermal capacity value will start decreasing as soon as
the overload condition is removed and therefore may vary depending upon how quickly after the
overload trip
$ 0(7(5,1*?02725 &$3$&,7< , momentarily short the Emergency Restart terminals and press the
reset key to reset the unit.
1. Alter the following setpoints:
6 3527(&7,21?3+$6( &855(17?81%$/$1&(?3+$6( 81%$/$1&( $/$50 21
6 3527(&7,21?3+$6( &855(17?81%$/$1&(?3+$6( 81%$/$1&( 75,3 2))
6 3527(&7,21?3+$6( &855(17?81%$/$1&(?3+$6( 81%$/$1&( $/$50 3,&.83 
6 3527(&7,21?3+$6( &855(17?81%$/$1&(?3+$6( 81%$/$1&( '(/$<  6(&
2. Connect the test set to inject current into phase A and phase C only. While viewing $ 0(7(5
,1*?&855(17?&855(17 81%$/$1&( 8% , slowly increase the current until the UNBALANCE ALARM
message comes on. Please note that the unbalance feature will not operate if the load is ≤ 30%
FLC. In the table below, record the injected current level at the point when the unbalance alarm
occurred. Use the formulae shown below to calculate percent unbalance using the currents
recorded in the table. Compare the calculated value to the displayed value on $ 0(7(5,1*?&85
5(17?&855(17 81%$/$1&( 8% and ensure they are match.
GE Multilin
Courtesy of NationalSwitchgear.com
actual injected current
=
$ 0(7(5,1*?02725 &$3$&,7<
the
239 Motor Protection Relay

8.4 PHASE CURRENT OVERLOAD

PHASE CT PRIMARY
×
---------------------------------------------------------- -
5 A
message

8.5 PHASE UNBALANCE ALARM

8 TESTING
100 A
×
--------------- -
10 A 200 A
= =
5 A
is viewed. After viewing
8
8-3