HindlePower AT30 SERIES Operating And Service Instructions page 60

SERVICING THE AT30
PROBABLE
SYMPTOM
CAUSE
LOW DC 1. Battery is
VOLTAGE discharged
indicator is on,
but ac & dc
breakers are
2. Low DC
closed
Voltage alarm
ac input and Float
voltage is voltage settings
normal, but are mismatched
there is output
3. Defective
current
rectifier bridge
4. Defective
Main Control PC
Board (A1)
5. Defective dc
circuit breaker
CB2
DC OUTPUT 1. Defective
FAILURE rectifier bridge
indicator is on,
but ac input
voltage is
2. Defective
normal, and
Main Control PC
ac & dc
Board (A1)
breakers are
closed
3. Defective
transformer T1
4. Defective dc
circuit breaker
CB2
56
RECOMMENDED ACTION
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 breakers. If the AT30 does not have
breakers (fuses instead), lock out ac and dc power to the AT30
externally. Wait one minute. Return dc power to the AT30 first,
followed by ac power. If the AT30 output voltage is normal, but
the LOW DC VOLTAGE indicator is still on, replace the Main
Control PC 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).
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 breakers. If the AT30 does not have
breakers (fuses instead), lock out ac and dc power to the AT30
externally. Wait one minute. Return dc power to the AT30 first,
followed by ac power. If the AT30 output voltage and current are
normal, but the DC OUTPUT FAILURE indicator is still on,
replace the Main Control PC 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).