Home » FAQ » How to fix variable frequency drive faults?

How to fix variable frequency drive faults?

Q: What are the faults occur in VFD? How to rectify the faults? Specially DC Bus voltage becomes more means what we have to do?

You should also look at the inertial load on the motor. A large inertial load will cause a greater regeneration level when the motor is slowing down. One way to correct for this is to increase the slow down ramp time, this should fix it albeit temporarily. If it is inertial in nature and quicker ramping is required, set up dynamic braking using a resistor and controller as mentioned earlier. Many variable frequency drives have the controller built in, so check your model's specifications.

If the VFD has DC bus overvoltage while stopped, check your incoming supply voltage. A high voltage excursion would cause this. The main power transformer taps may need to be changed in that case. If the power company's voltages vary too greatly, request the power company to install automatic tap changers on their transformer. Otherwise the only solution would be to use a regulated DC power supply and feed DC directly to the VFD and abandon the AC front end on the variable frequency drive.

DC Bus becomes more means DC Bus Overvoltage, ie. DC Bus voltage exceeded its trip point.

For 200 V Class VFD - Trip Point is 410 V
For 400 V Class VFD - Trip Point is 820 V

1. You should check input voltages and frequency
2. The Dynamic Breaking Resistance value to be check, should be compatible as per the load selection and VFD ratings.

Post a Comment:

Plz Calculate (8 + 8) =
(Your comment will show after approved.)

You may also like:

Featured Articles
Non-Enclosure Variable Frequency Drive ... Non-Enclosure Variable Frequency Drive (VFD)No enclosure (cover), reducing installation space and cost effective. Widely used in All-In-One control cabinet. Keep the same ...
Variable frequency drive application ... Variable frequency drive application guideVariable Frequency Drive (VFD) can be used in lots of fields. Variable frequency drives are widely used to control the speed of ...
Variable frequency drive in HVAC ... Variable frequency drive in HVAC systemsVariable frequency drives (VFD) have been used for HVAC systems in buildings for more than 40 years. But only in recent years, ...
Variable Frequency Drive Harmonics and ... A discussion of the benefits of variable frequency drives often leads to a question regarding electrical harmonic distortion ...
Three phase inverters Three phase invertersIn the variable frequency drive rectifier paper, it explains how to go from three phase alternating current voltage to a direct ...
Variable Frequency Drive Service
VFD manufacturers
Variable Frequency Drive Sales Email buy@vfds.org
Variable Frequency Drive Support Email tech@vfds.org