HindlePower AT30 SERIES Operating And Service Instructions page 54

SERVICING THE AT30
PROBABLE
SYMPTOM
CAUSE
DC breaker 1. Battery
trips (or fuses connected with
clear) reverse polarity
immediately
2. Defective
rectifier bridge (if
unfiltered AT30)
3. Defective
Free-Wheeling
diode CR4
4. Defective
Polarity Diode
CR1 (if filter
assembly is
installed)
5. Defective
wiring
DC breaker 1. Loose
trips (or fuses connection to
clear) after a breaker
few minutes
2. Open SCR
3. SCR not
controllable
4. Defective
Gate Driver PC
Board (A15)
5. Defective
Main Control PC
Board (A1)
50
RECOMMENDED ACTION
1. Check and correct battery wiring if necessary.
2. Test by disconnecting wires # 7, 8 & 9 at the rectifier module(s)
(A16) mounted on the main heat sink(s), or at the main
transformer (T1). Measure resistance between the ac terminals
(bottom terminals) on the rectifier module(s). It should be at least
Ω
100,000 (check both polarities). If resistance is low in either
direction, replace the rectifier module(s) (A16) as needed.
3. Disconnect wire # 15 from SCR module mounted on the heat
sink assembly or from the positive bus bar. Measure the
resistance through the Free-Wheeling diode (CR4). Check both
polarities. It should be at least 100,000
Ω
than 1,000 in the other polarity. Replace CR4 if it is defective.
4. Disconnect wire # 17 from the dc circuit breaker (CB2), or the
optional dc fuse (F3). Measure the resistance through the Polarity
Diode (CR1), mounted to the negative filter capacitor bus bar.
Check both polarities. It should be at least 100,000
polarity, and less than 1,000
if it is defective.
5. Check spacing of terminals and check wiring for signs of
insulation damage, burns, etc. Repair as necessary.
1. Check and tighten connections as required.
2. 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).
3. Disconnect the wire harness plug from connector J26 on the
top of the Gate Driver PC Board (A15) and restart the AT30. If
you are able to measure output current, one of the SCRs is
defective. Replace the rectifier module(s) (A16) as needed.
4. If the front panel meter displays more than 110% of rated dc
current, the Gate Driver PC Board (A15) may be defective.
Unplug A15 from the Main Control PC Board (A1). If the output
current does not drop to zero, replace the Gate Driver PC Board
(A15).
5. If the front panel meter displays more than 110% of rated dc
current, the Main Control PC Board (A1) may be defective.
Unplug the system harness connectors (J25 and J26) from the
Gate Driver PC Board (A15). If the output current drops to zero,
replace the Main Control PC Board (A1).
Ω
in one polarity, and less
Ω
Ω
in the other polarity. Replace CR1
in one