Exide Technologies Section 94.30 - Manual (Page 60)

SERVICING THE AT10.1
56
SYMPTOM PROBABLE
CAUSE
RECOMMENDED ACTION
LOW DC
VOLTAGE
indicator is
on, but ac
and dc
breakers are
closed; ac
input voltage
is normal;
there is
output current
1. Battery is
discharged
2. Low DC
Voltage alarm
and Float
voltage settings
are mismatched
3. Defective
rectifier bridge
4. Defective
Main Control
board A1
5. Defective dc
breaker (CB2)
1. After an ac power failure, or a battery discharge for any
other reason, it may take several hours to recharge the
battery. It is normal for the
LOW DC VOLTAGE indicator to be
on until the battery voltage is above the Low DC Alarm
voltage.
2. Be sure that the Low DC Voltage alarm setting is lower than
the Float voltage setting. See Sections 2.3.2 and 2.3.4.
3. Use a clamp-on ammeter to measure the current in wire #
5
or # 6, between the transformer (T1) and the rectifier modules.
If it less than 50% of the dc output current, one of the SCRs or
diodes is defective. Replace the rectifier module.
4. Turn off both front panel circuit breakers (or turn off ac and
dc power externally if the charger doesn’t have breakers).
Then turn on the dc breaker, followed by the ac breaker. If the
charger output voltage is normal, but the
LOW DC VOLTAGE
indicator is still on, replace the Main Control board (A1).
5. Disconnect the battery, and connect a light dc load to the
charger. Measure the dc voltage across TB1(+) and TB1(-),
with the breaker on. If no voltage is measured, replace the dc
circuit breaker (CB2).
DC OUTPUT
FAILURE
indicator is
on, but ac
and dc
breakers are
closed; ac
input voltage
is normal 1. Defective
rectifier bridge
2. Defective
Main Control
board A1
3. Defective
transformer T1
4. Defective dc
breaker
1. Use a clamp-on ammeter to measure the current in wire # 5
or # 6, between the transformer (T1) and the rectifier modules.
If it less than 50% of the dc output current, one of the SCRs or
diodes is defective. Replace the rectifier module.
2. Turn off both front panel circuit breakers (CB1/CB2). If the
charger does not have breakers but fuses (F1/F2 and F3/F4),
turn off ac and dc power externally. Start up by turning on the
dc breaker, followed by the ac breaker. If the charger output
voltage and current are normal, but the
DC OUTPUT
FAILURE indicator is still on, replace the Main Control board
(A1).
3. Use an ac voltmeter to measure the ac voltage from T1-X1
to T1-X5. It is normally 50% to 80% higher than the rated dc
output voltage. If it is too low, check the wiring of the primary
taps. See Changing Transformer Taps, Section 1.6. If it is
zero, replace the transformer (T1).
4. Disconnect the battery, and connect a light dc load to the
charger. Measure the dc voltage across TB1(+) and TB1(-),
with the breaker on. If no voltage is measured, replace the
breaker.