Exide Technologies Section 94.40 - Manual (Page 60)

SERVICING THE AT30
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
circuit 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 wires #
7, 8
& 9, between 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(s) (A16) as needed.
4. Turn off both front panel circuit breakers (CB1/CB2), or turn off
ac and dc power externally, if the AT30 does not have breakers.
Wait one minute before returning the dc connection, followed by
the ac connection. 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 AT30.
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 input
voltage is
normal, and
ac & dc
breakers are
closed 1. Defective
rectifier bridge
2. Defective
Main Control
board A1
3. Defective
transformer T1
4. Defective dc
circuit breaker
CB2
1. Use a clamp-on ammeter to measure the current in wire # 7, #8
and # 9, between T1 and the rectifier module(s). 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), or turn off
ac and dc power externally, if the AT30 does not have breakers.
Wait one minute before returning the dc connection, followed by
the ac connection. 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 between the
transformer secondary taps (T1-X1, T1-X2 & T1-X3). The line-to-
line voltage is normally the same as the rated dc output voltage. If
it is too low, check the wiring of the transformer primary taps (T1-
H1, T1-H2 & T1-H3). See Section 1.6 for details. If the ac voltage
on the transformer secondary taps is
zero, replace T1.
4. Disconnect the battery, and connect a light dc load to the AT30.
Measure the dc voltage across TB1(+) and TB1(-), with the
breaker on. If no voltage is measured, replace the dc circuit
breaker (CB2).