Servicing the at30 – Exide Technologies Section 94.40 User Manual
Page 55

SERVICING THE AT30
51
SYMPTOM PROBABLE
CAUSE
RECOMMENDED ACTION
No output 
current, and 
AC ON lamp 
is out, but ac 
and dc 
breakers are 
on 
1. AC supply 
failure 
2. Input fuse 
F1A/B/C blown 
 
 
 
 
3. Defective 
wiring 
 
 
 
 
4. Defective 
transformer T1 
1. If the
AC ON indicator is out, check the feeder circuit breaker or
fuse.
2. Remove the ac fuses (F1A, F1B and F1C) from the fuse 
holder(s) and check if blown with an Ohmmeter or fuse tester. 
Replace F1A, F1B, and/or F1C as needed. 
NOTE: If the replacement fuses immediately blow, see the 
Sections titled "AC breaker trips immediately" and "AC breaker 
trips after a few minutes" for further troubleshooting hints. 
3. Check terminals and wiring between T1 and the rectifier bridge 
assembly, main inductor (L1), dc filtering assembly (if present), dc 
breaker (CB2), optional dc fuses (F3/F4), and the output terminals 
(TB1+/-). Check wires # 
42 through # 45 from T1-Y0 through T1-
Y3 to the Gate Driver pc board connector (J25). Repair as 
necessary. 
4. Use an ac voltmeter to measure the ac voltage from T1-X1 to 
T1-X2 and T1-X3. It is normally 50% to 80% higher than the rated 
dc output voltage. If it is too low, check the wiring of the 
transformer primary taps (T1-H1 through T1-H3). See Section 1.6 
for details. If the ac primary voltage is 
zero, replace the T1.
No output 
current, but 
AC ON lamp 
is on, and ac 
and dc 
breakers are 
on 
1. Battery is fully 
charged 
2. Float or 
Equalize voltage 
set too low 
3. Wrong ac 
input voltage, or 
mistapped T1 
4. Defective 
wiring 
 
 
5. Defective 
rectifier bridge 
 
 
6. Defective 
Gate Driver pc 
board A15 
7. Defective 
transformer T1 
 
 
 
 
8. Defective 
inductor L1 or L2 
 
9. Defective dc 
breaker (CB2) 
1. This is normal operation in a system with little or no dc load. As 
long as the AT30 maintains Float voltage, it is operating normally. 
2. Check the Float and Equalize voltages and adjust them if 
necessary. Consult your battery manufacturer for the proper 
voltage settings. 
3. Be sure the transformer primary taps (T1-H1, H2 and H3) are 
wired correctly for your input voltage. See Section 1.6 for details. 
 
4. Check terminals and wiring between T1 and the rectifier bridge 
assembly, main inductor (L1), dc filtering assembly (if present), dc 
breaker (CB2), optional dc fuses (F3/F4), and the output terminals 
(TB1+/-). Repair as needed. 
5. Use an ac voltmeter to measure the voltage between the SCR 
gate leads on each SCR module. If you measure about 1.0V rms, 
but there is no output current, replace the rectifier module(s) 
(A16) as needed. 
6. If you do not measure any ac voltage in step 5 above, and the 
battery voltage is less than the Float voltage setting, replace the 
Gate Driver pc board (A15). 
7. 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.
8. Disconnect the wiring from inductor (L1) and measure the 
resistance between the terminals. If it is an open circuit, replace 
L1. Repeat for inductor (L2) if the optional dc filter is installed. 
9. Disconnect the battery, and connect a light dc load to the AT30. 
Measure the dc voltage across TB1(+) and TB1(-), with the dc 
circuit breaker (CB2) on. If no voltage is measured, replace CB2. 
