Baldor VFD Bus Undervoltage fault

[Aerik]

VFD noob back again with another drive question! So anyhow, I've got a Baldor VFD 15H with an OE suffix.. Had a fuse blow feeding a bus box (feeds about 8-10 motors, including the motor driven by VFD..) After replacing the fuse, maybe a week or so later, I went to use the drive, and it gave a bus undervoltage fault.. and continues to do so ever since..

The manual says the input voltage is too low, but it's not. (3 phase 460V) also recommends disconnecting the dynamic brake hardware, but there is none..

Any ideas on why I'm getting this fault, and how to possibly fix it?

Again, it's a Baldor VFD 15H, OE suffix. Drives a 20hp gear motor (confirmed in working order after bypassing VFD) at 460V 3ph in/out, not using any DB

Thanks in advance!

 

[jraef]

You have probably lost a diode (or SCR as the case may be with that drive) on the input rectifier.


"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> faq731-376

 

[itsmoked]

Yeah busticated VFD. The fuse may have been the last hurrah.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[ozmosis]

agree with jraef-do a diode check on each phase and you will probably find one gone.

 

[Aerik]

Thanks a lot guys, for a point in the right direction, or at the very least a point in any direction

Will get back with you when I get a chance to test it out