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What causes overvoltage fault on VFD?
A VFD overvoltage fault can occur on power up, during deceleration, acceleration, during normal run, or while sitting idle. The VFD overvoltage fault may occur from ground noise coming back in through these capacitors causing a rise on the DC bus.
What can cause a DC bus overvoltage fault?
Possible causes:
- The Input voltage is too high.
- Improper floating ground or high input voltage on one of the phases.
- There are power spikes or surges at the input.
- The drive is going into regeneration (regen).
- Rapid load change is causing a large spike in the DC Bus.
What causes overvoltage in a motor?
Overvoltage occurs when the supply voltage rises above the rated voltage of the equipment or motor. Overvoltage can be caused by poor regulation of a power source from a utility company, oversized transformers, uneven or varying circuit loading, wiring errors, and electrical insulation or isolation failures.
Can a VFD change voltage?
A variable frequency drive (VFD) transforms the input mains of constant voltage and frequency into a voltage and frequency range that can be varied to control motor torque.
What causes the VFD to trip during deceleration?
If IPM module overcurrent or ground wire short circuit causes the VFD trip in deceleration, generally it’s the top half-bridge module or drive circuit fault; If IPM module overcurrent during acceleration, then it is the next half-bridge module or drive part fault.
When does a VFD fault occur during power up?
A VFD overvoltage fault can occur on power up, during deceleration, acceleration, during normal run, or while sitting idle. If the VFD overvoltage fault occurs during power up, the first thing to check is the incoming line voltage with a meter. If the line voltage is within specifications, find the jumper used to ground the common capacitors.
When to use a dynamic brake for a VFD fault?
If extending the deceleration time does not solve the VFD overvoltage fault, a dynamic brake may be required to dissipate the excess energy. A dynamic brake is a resistive device that takes energy from the bus and burns it off as heat. The only other solution is to reduce the inertia on the load to the motor.
What should I do if my VFD is overcurrent?
If it’s the variable frequency drive problem, we can check the trip current from the VFD operation history, to see if the current exceeds the VFDs rated current or electronic thermal relay settings value. If three-phase voltages and currents are balanced, we should consider overload or sudden change situations, such as motor stall.