VFD's Tripping

[kwired]

And there we get to the purpose of a line reactor. If you have a small drive on a big transformer it cannot handle the available current. It can also block harmonics (the “rabbit ears” current pattern).

but that available current isn't flowing unless something in the drive front end fails, at that point there is nothing left to protect as it has already failed, all the reactor will do is limit how spectacular the failure may be to watch.

 

[ptonsparky]

but that available current isn't flowing unless something in the drive front end fails, at that point there is nothing left to protect as it has already failed, all the reactor will do is limit how spectacular the failure may be to watch.

From what I understand the LR also limits the flow of current to the capacitors as they are first charged.

 

[kwired]

From what I understand the LR also limits the flow of current to the capacitors as they are first charged.

It does. Some also have precharge resistors.

 

[wirenut1980]

The fact that the VFD tripping is happening more often during thunderstorms makes me think that they may be tripping due to voltage sags (dips) than a transient of some sort. But fault codes should help clear up the cause of the trips. Do the VFD's trip any other times besides thunderstorms?

Line reactors are a great investment for VFD's. They help reduce trips due to utility capacitor switching transients, and help reduce harmonic current distortion.

 

[PaulMmn]

The problem with MOVs is that they are 'sacrificial--' every time they swallow up a transient, a little bit of them gets eaten away-- until (as someone said) they end up as an open or short circuit. I'm familiar with the 'home version' of line reactors-- the Zero Surge / Brick Wall surge protectors, with 'reactors' (ie coils of wire with iron cores and capacitors) inside them, which 'absorb' a surge and release it slowly (NOT to the ground line!).

I've had 4 Zero Surge units for years, and (knock on wood) have not had issues with power surges. I have heard the one guarding my computer HUMMMmmmm during storms, so there's hope they're still working properly!