Identifying Component Faults
1 Identifying AC SPD Faults
Check the color of the AC SPD indication window. Green indicates that the AC SPD is normal. Red indicates the AC SPD is faulty.
2 Identifying Circuit Breaker Faults
The following indicate that the circuit breaker is faulty:
l The circuit breaker cannot be switched to ON/OFF after the short circuit fault for its end circuit is rectified.
l When the circuit breaker is switched to ON and its input voltage is normal, the voltage between the two ends of the circuit breaker exceeds 1 V.
l The input voltage is normal, but the resistance between both ends of the circuit breaker is less than 1 kΩ when the circuit breaker is OFF.
3 Identifying Rectifier Faults
A rectifier is damaged if any of the following conditions is not met:
l When the rectifier does not communicate with the SMU and the AC input voltage is around 220 V, the green indicator on the rectifier is steady on, the yellow indicator is blinking, the red indicator is off, and the rectifier output is normal.
l The SMU can perform equalized charging, float charging, and current limiting control for the rectifier when the communication cable to the rectifier is correctly connected and communication is established between the rectifier and the SMU.
4 Identifying SMU Faults
The following indicate that the SMU is faulty:
l The DC output is normal but the green indicator on the SMU is off.
l The SMU breaks down or cannot be started. Its LCD has abnormal display or buttons cannot be operated.
l With alarm reporting enabled, the SMU does not report alarms when the power system is faulty.
l The SMU reports an alarm when the power system is not faulty.
l The SMU fails to communicate with the connected lower-level devices even though the communications cables are correctly connected.
l Communication between the SMU and all rectifiers fails even though the rectifiers and the communications cables are normal.
l The SMU cannot monitor AC or DC power distribution when communications cables are intact and AC and DC power distribution is normal.
l Parameters cannot be set or running information cannot be viewed on the SMU.
