General Troubleshooting Procedures - Siemens L-828 Manual

L-828 CCRs LC-Type (4, 7.5, and 10 kW/6.6 A/60 Hz)
4. General Troubleshooting
Procedures
(contd.)
Problem
3. Regulator
repeatedly trips
circuit breaker CB1
on Start-up.
4. Regulator shuts
down from
overcurrent
protection (red LED
lit)
 2002 Siemens Airfield Solutions, Incorporated
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Possible Cause
Feedback transformer T2 or main
transformer T1 failed
SCR1 shorted
Control PCB failed
Faulty overcurrent protection
CCR not properly calibrated
SCR1 fails
Control PCB or SCR1 fails.
96A0104B
Issued 6/02
Troubleshooting
Corrective Action
Turn control switch S1 to the OFF
position. Reset circuit breaker CB1. While
observing the CCR's output ammeter, turn
on the CCR. If the meter moves, go to the
corrective action below. If the meter
does not move, replace feedback
transformer T2 or main transformer T1.
With CB1 and control switch S1 off,
remove connector J4 by pulling it from
the PC board. Then turn on the circuit
breaker CB1 and control switch S1. If
circuit breaker CB1 still trips, replace
SCR1.
Replace Control PCB.
Test the operation of the overcurrent
protection (red LED on). With the CCR
off, connect a jumper across TP7 to TP9
(see Figure 8-1). Turn on the CCR to an
output of 6.6 A, and time how long it
takes for the overcurrent protection to
shut off the CCR. Green REGULATOR ON
LED will turn off when the overcurrent
circuitry operates. The time period will be
20 ±10 seconds from proper operation. If
the time period is less than 10 seconds or
more than 30 seconds, the CCR may be
improperly calibrated.
With CB1 and control switch S1 off,
remove connector J4 by pulling it from
the Control PC board. Then turn on
circuit breaker CB1 and then control
switch S1.
Replace SCR1.
NOTE: SCR1 may have failed if
overcurrent indicator (red LED) does not
light.
Replace SCR1 or Control PCB.
NOTE: SCR1 or Control PCB may have
failed if overcurrent indicator (red LED)
lights.
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