Unipower ARR-M Series - Page 88

BATTERY CHARGER USER’S MANUAL PART- 2: THEORY OF OPERATION
MCEnPC23-REV.2.4 Page 83
Fault Possible root cause Recommendation
No DC Output
1. Open AC Breaker;
2. AC Input failure;
3. DC fuse blown;
4. Open blocking diode;
5. Open or loose connection;
6. Control board failure;
7. SCR module failure;
8. High Volt Shutdown alarm;
- Verify that AC breaker is closed ("ON"). Check for AC voltage on both sides of
the breaker;
- Verify that the AC supply is of correct voltage and frequency;
- Verify the DC output fuse;
- Check blocking diode (if provided);
- Check all wiring from Input to Output for open or loose connections (Refer to
schematic);
- Replace control board;
- Verify SCR modules and replace if needed;
- In case of High Voltage Shutdown Alarm: Turn OFF the AC and DC breakers
for 5 minutes then restart;
DC fuse blows or
DC breaker trips
1. Freewheeling diode failure;
2. Control board failure;
3. SCR module failure;
4. Battery connections reversed;
5. DC filter failure;
- Check the freewheeling diode for short circuit;
- Replace control board;
- Verify SCR modules and replace if needed;
- Verify polarity of battery connections;
- Check for shorted DC filter Capacitor;
AC breaker trips
1. Short circuit;
2. SCR, Diode or control board
failure;
- Check for shorts from Input to Output connections (Refer to schematic);
- Replace defective component;
Low voltage alarm
- Charger overload;
- AC Input failure;
- Float, equalize and/or low
voltage alarm adjustments
affected;
- Check if the charger is in the current limit mode. Check the load for problems;
- Verify that the AC supply is of correct voltage and frequency;
- Refer to the adjustment procedures to reset;
High ripple voltage
1. AC line is too high;
2. Defective filter capacitor;
3. SCR, Diode or control board
failure;
- Read Input voltage and rectify the problem. Verify that the AC supply is of
correct voltage and frequency;
- Disconnect the capacitor(s) to observe any change in the output voltage ripple.
Replace capacitor(s) if needed;
- Replace defective component;