SECTION 8. TESTING AND TROUBLE- SHOOTING
WARNING: Do not change taps on the current sen- sors or adjust the trip unit settings while the breaker is carrying current. Failure to adhere to these instructions will void all warranties.
Testing
Before installing a converted breaker back into service, perform the following steps:
1.Verify that the trip unit is securely installed by performing a continuity test on the CT wiring and the trip unit.
a.Disconnect the black CT wires at each phase sensor.
b.Check for continuity with a continuity tester or VOM from the white lead of the phase A CT to the white lead of the phase B CT.
c.Repeat this continuity test for the white leads of the phase A and phase C CTs.
d.Measure the resistance across each phase sensor and compare the values measured to the values listed in Table 1.
e.Reconnect the black CT leads to all of the phase sensors. Ensure that this is done before continuing with performance testing of the breaker.
CAUTION: In addition to the continuity test described in Step 1 and before performance testing of the converted breaker, each phase of the breaker should be primary injected with a current level of about 10%, but no more than 20%, of the CT rating. During the application of test current, activate the trip unit screen by depressing the battery button on the trip unit face and check that the test current is displayed on the screen for each phase tested. If the trip unit fails to display the test current, stop the test immediately and verify the installation of the trip unit and wire harness before proceeding with any additional testing.
WARNING: If the converted breaker is energized or tested by primary injection with a sufficiently high test current with a loose or open circuit between the CTs and the trip unit, damage will occur to the trip unit, wire harness,
2.Check the insulation on the primary circuit with a
3.Measure the resistance across the line and load terminals for each phase using a
ter or millivolt tester. If the resistance differs considerably from phase to phase, the electrical connections may not be properly tightened or it could also indicate improper contact wipe.
4.To verify that the breaker has been properly retrofitted, perform a primary injection test on each phase. This test will check the CTs, bus, wiring harness, flux shifter, and trip unit as a complete system.
a.A
b.Set the
c.When ground fault is installed, the test can be performed by wiring two adjacent poles in series or by using the GE Digital Test Kit, cat. no. TVRMS2. This will prevent the breaker from tripping because of an unbalanced cur- rent flow.
CAUTION: Do not attempt to use GE Test Kit cat. no. TVTS1 or TVRMS on this trip unit.
Trouble-Shooting
When malfunctioning is suspected, first examine the breaker and its power system for abnormal condi- tions such as the following:
•The breaker is not tripping in response to over- current conditions or incipient ground faults.
•The breaker is remaining in a
•The shunt trip (if present) is activating improp- erly.
Nuisance Tripping on Ground Fault-Equipped Breakers
When nuisance tripping occurs on breakers equipped with ground fault trip, a probable cause is the existence of a false ground signal. Each phase sensor is connected to summing circuitry in the trip unit. Under
The sensors and their connections should be closely examined if nuisance tripping is encountered on any breaker whose ProTrip trip unit has previously demonstrated satisfactory performance. After dis-
23
