What causes motor overvoltage?
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.
What is a over voltage fault?
Topic Description. An OV (DC Bus Overvoltage) fault is triggered when the DC bus voltage rises higher than the overvoltage trip point. Note: On smaller drives with a LED segment display such as the V1000 and J1000, a DC Bus Overvoltage fault will appear as “oU”.
What is dc bus voltage?
The dc bus voltage is relative to the peak voltage of the mains input. dc bus voltage is ~1.414 x the rms line voltage (e.g., for a 480V ac drive, the dc bus should be ~678V dc. A dc voltage value that is too low can cause the drive to trip.
What to do if your DC BUS is overvoltage?
If you measured the extra high voltage some time after the fault I have no answer. Try starting the unit without a load , or at least a very light load. High harmonics can create that error, you may have very high voltage spikes on your ac input and the vfd rectify them.
What should the voltage be for an overvoltage fault?
Comparing Overvoltage trip thresholds with the nominal DC bus voltage we can see that the overvoltage trip settings for most drives is 130-150% of nominal DC bus voltage. Corresponding AC voltage at which overvoltage fault occurs can be calculated by dividing the above values by 1.35.
What is the voltage of a DC BUS?
The VFD and motor can take voltages from 400 to 500V, 3-phase. My voltage is 470, 471, 472 phase to phase. Right after I apply power to the combo unit I get the DC bus overvoltage fault. I’m not able to enable the drive because it faults right away.
How does overvoltage protection work on a drive?
Remember that the overvoltage protection on drives is based on the measured DC bus voltage. There is a time delay between when transient overvoltage on the AC side occurs and the time the DC bus gets boosted in voltage.