TROUBLE-SHOOTING VFD FAULTS
When an Electric Motor drive goes down, it’s time to check the VFD. VFDs have troubleshooting checkpoints and it’s time to check the basics:
CHECK THE CONTROLLER DISPLAY: Most VFD controllers have an interface that displays information about the drive’s operation. This interface might display high current (which could lead to blown fuses), high and low voltages, high temperatures, internal faults, etc.
CHECK THE CONNECTIONS: Loose connections could cause faulty operations. A routine check could help you determine if the connection is loose. A voltage drop check could also be down while still powered up.
CHECK TEMPERATURES: Another way a VFD fault can be troubleshot is by using a temperature probe or IR thermometer to check the temperature of the connections.
CHECK A LITTLE CLOSER: In new installations, apparent problems with drive performance are often due to improper application, drive selection, setup, or installation of the motor or drive.
In the event of frequent breaker trips, you might have to examine protection coordination to ensure the breakers are the right size from the drive back to the service. You might also need to check other branch and feeder circuits.
Other areas you might need to check includes:
- Oscilloscope (Voltage notching)
- Inductive noise in power wiring, signal or control
- Cable routing
- Damaged signal, control, or power wiring and
- Control display.