VFD Trips on Overvoltage Fault? Ac drives shows overvoltage error
My Drive Shows This Fault
- AB ( Allen Bradley ) – Fault F3
- ABB – Fault A2002
- Danfoss – Fault 7
- Delta – Fault ov
- Fuji- Fault OV1, OV2 and OV3
- Hitachi – Fault 2, E07.3 and E07.4
- Schneider – Altivar Fault ObF
- Siemens Fault F30002
- Toshiba – Fault OP1, OP2 and OP3
When drive trips on Overvoltage please follow the following steps to solve it.
VFD Trips on Overvoltage in three conditions. During acceleration, Deceleration and during constant Speed. Try to identify when does it exactly trips. Some Drives shows in fault itself when is drive trip with different Error codes.
When there is overvoltage error first step is to check input voltage. It should be in rated input voltage range described by drive. For Example If Inverter drive is Three phase 380V-480V. +-10% Maximum voltage at which VFD can Work is 480+48=528V.
Check the input voltage at input terminals of VFD. It should be well below rated maximum Input voltage.
If it is more than rated voltage correct it.
If Voltage in within the rated input voltage check the DC Bus Voltage. It should be approximately 1.5 times input voltage at the time of Fault. If it is more than that than it means motor is generating voltage which is feed back to Drive. This is called as back emf.
Back emf is generate at different points of operation. It may be at constant speed or at acceleration and deceleration.
Overvoltage During Deceleration
Application which have large inertia, such as fan may produce back emf During deceleration. This voltage is feed back to ac drive, which raises dc bus voltage due to which dive goes into error. In this case you try to increase the deceleration time(Ramp down time). If the problem still exists set your VFD to coast to stop if your application permits. Coast to stop means your Drive will get isolated from motor on the execution of stop command, which will let your motor to stop it itself with respect to its inertia. But if your application does permits to stop at its own inertia and you want to stop VFD in specific time than you need to connect Braking resistor at the output of Drives DBU (Dynamic braking Unit) or Braking Chopper unit. Some of the drives comes with in-built Braking chopper. If they doesn’t come with DBU you need to connect one externally. You can in our product list whether your drive has inbuilt Braking chopper or not.
Overvoltage During acceleration
If overvoltage occurs during acceleration, Please increase the acceleration time/ ramp up time. If the fault still exists change the acceleration pattern to S-curve or install braking resistor to control the load and decelerate.
OverVoltage During Constant Running
If the fault Occurs during Constant Running Check the Input Supply Voltage. If it Is within the range check for Output cable of Motor and Motor health.
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