Fault phenomenon: UPS input undervoltage (overvoltage) alarm

Fault phenomenon: UPS input undervoltage (overvoltage) alarm            

Fault analysis: 

1. After AC is power off, the input voltage of UPS is 0V , which is less than alarming threshold (180V)            

2. UPS sampling AC input voltage is more than overvoltage alarming threshold (250V)            

Troubleshooting:            

1. check whether the external AC220V power supply is normal. 

Previous:Fault phenomenon: environmental EN-MG alarm

Next:Fault phenomenon: downside standing-wave ratio warning