Power Dips and Surges!

[Coachmike]

Card dealership is experiencing an intermittent power dip on the B phase of a 3 phase 480 volt 800 amp service. This phase loss is causing an HVAC unit's VFD to trip and show an overvoltage fault. Of course, the utility is saying it is not their issue and neighbors do not have the problem. Any insight is appreciated. TIA

 

[ron]

You need to install a recording meter to show the utility what is occurring. The recording meter may also show a failing VFD

 

[David Castor]

Overvoltage fault and not undervoltage? I'd check the setpoints in the VFD first.

 

[Jraef]

Phase loss causing an OVER voltage fault on a 480V VFD might be related to it being a 480V DELTA system and a VFD that doesn't play well with delta.