Exide Technologies Section 94.20 - Manual (Page 61)

SERVICING THE AT10.1
57
SYMPTOM
PROBABLE
CAUSE
RECOMMENDED ACTION
POS GND or
NEG GND
indicator is on 1. Ground fault
on external dc
bus
2. DC circuit
breaker is open
and NEG GND
indicator is on
3. Alarm needs
calibration
4. Defective
wiring
5. Defective
Main Control
circuit board A1
1. Disconnect the AT10.1 from the battery and dc bus, and
check the battery and dc bus for a ground fault.
2. If the AT10.1 has been placed into standby by opening the
dc breaker (CB2), the ground detection circuit gives an
erroneous alarm. Close the dc breaker and the alarm should
end. If you want the AT10.1 to be in standby, open the ac
circuit breaker (CB1).
3. Calibrate the ground detection sensitivity. See Section
2.3.4.
4. Disconnect the AT10.1 from the battery and dc bus. Turn
the AT10.1 back on, and measure the voltage from TB1(+) to
chassis, and from TB1(-) to chassis. The voltage readings
should be equal, each approximately half of the total output
voltage. If there is more than a 10% imbalance, turn off the
AT10.1, and inspect all wiring from TB1(+/-) to the dc circuit
breaker (CB2), and the rectifier bridge to the dc filter inductor
(L1). Look for evidence of insulation damage, insufficient
spacing between terminals and chassis, or wires run too close
to metal edges.
5. Turn off both front panel circuit breakers (CB1/CB2). Turn
on the dc breaker, followed by the ac breaker. Wait one minute
before returning the dc connection, followed by the ac
connection If you are sure there is no ground fault on the
external bus or within the AT10.1, but the POS GND or NEG
GND indicator is still on, replace the main control circuit board
(A1).
Summary
alarm relay is
in alarm
mode, but no
front panel
alarm
indicator is on 1. Defective
Main Control
circuit board A1 1. Turn off both front panel circuit breakers (CB1/CB2). Then
turn on the dc breaker, followed by the ac breaker. Wait one
minute before returning the dc connection, followed by the ac
connection. If the relay remains in alarm mode, check the Low
Level Detect indicator on main control circuit board. See
Section 2.3.8. If no other alarm is on, replace the main control
circuit board (A1).