Effective 8/2006
Page 21
I.L. 66A7534H04
Note:
For circuit breakers with 100A thru 400A sensors
the
Ground Fault Setting
could be raised or turned
OFF
and either “Long Time” or “Short Time” tests could be
conducted. Adjusting the
Long Delay Setting
to 0.4x
would help to minimize the current requirements to
simulate to overload levels.
The above test essentually proves out the sensor wiring,
the rating, the rating plug as well as polarity of the CH
Type-V current sensors and tripping of the circuit breaker.
5.4.2.3 Secondary Injection Testing
If desired, further testing can be done by injecting test
current across the CH Type-V current sensor’s output
terminal screws or injecting directly into the circuit
breaker’s secondary contacts (A-4, A-19) or (A-5, A-20) or
(A-6, A-21)
(See Figures 1.5 and 5.5)
Note:
If the circuit breaker is out of the cell, it may be
beneficial to make a test harness.
The test harness will
have female AMP sockets (#66598-2) in one housing on
the one end. The other should consist of spade
terminations that connect to the
5A
and
Common
posts on
the MS-2 current source.
An inductor (Signal Transformer CL-1-2) or 25 ohm resistor
should be placed in series with the red terminal post to
stablize the output for currents less than 1.5 amperes.
Attach the separate True RMS ammeter in series with this
component. The rest of the wiring is direct to the phase
input secondary contacts.
Hook up a circuit breaker
Aux Switch
to the MS-2 tester’s
Contacts
terminals to stop the clock and the source of
current.
TEST 2. Continue ramping up current and the circuit
breaker should trip via ground element between 40 to 50%
of plug rating.
This test arrangement checks both the phase current
sensor and the residual ground element since a single
pole is energized.
(See Figure 5.3)
TEST 3. Repeat Test 1 and 2 on other two poles.
TEST 4. Connect primary current circuit such that two
circuit breaker poles
(See Figure 5.4)
are in series and
ramp current up to 40% of plug rating. The Digitrip’s
Unit
Status
LED should now flash at about 15% rating plug
value with two poles energized. Continue ramping up
current toward 40%. The circuit breaker should not trip. If
the CH Type-V current sensor’s polarities are incorrectly
wired, the circuit breaker will trip out on ground fault at
about 20%. If a ground fault trip occurs, check secondary
wiring of CH Type-V current sensors for proper polarity.
Test Procedure:
TEST 1. Close circuit breaker and ramp up current using
the
Output Control
knob of MS-2 and by setting selector
switch to the
Maintain
position. At about 30% of the
Rating Plug value, check for the green
Unit Status
LED to
flash consistently at a one second interval.
(See Figure
1.1)
Suitable
Conductors
Low-Voltage
ac Current
Source
A
B
C
Polarity &
Identification
Suitable
Conductors
A
B
C
Polarity &
Identification
Shorting
Conductors
Low-Voltage
ac Current
Source
Figure 5.3 Connection Details to verify a trip (Ground)
Figure 5.4 Connection Details to verify Sensor Polarities