CLanford
Member
Hi Everyone,
Yesterday we encountered an issue where I had a 480V 3Ph 2HP Powerflex 525 blow up. Upon further inspection, we noticed that 10 other VFD's had also been taken out in the process. There were no internal power surges in the plant (we have facilities in place at the switch gear to protect over/undervoltage, loss of phase situations, etc), but I believe that one drive in particular blew its caps up and that surged the panel, taking out other VFD's. Upon troubleshooting, no phase-to-phase, dead short other ground fault issues were found in any part of the panel or any of the field devices.
The panel has 28 identical 525's that are zero-stacked (aka literally side-by-side mounted across the DIN rails), are individually protected by Eaton 4-6.3A adjustable MCCB's and all are fed from a 200 amp disconnect
My question is, what can be done to prevent one VFD explosion from taking out others? I've heard that using J-class fuse blocks instead of MCCB's will help as them blowing may prevent a cap-exploding VFD panel surge from passing onto neighboring drives. I don't want to create nuisance blown fuses by just replacing the MCCB's with fuses but I need to do something different. I was thinking about putting fuses upstream of the MCCB's, but rating them at some arbitrary value above the MCCB limits. Does this sound reasonable?
One caveat: I am making an assumption here that the one VFD failing was the cause of the others, so I'd also like hear any other ideas that could have caused it.
Thanks!
Yesterday we encountered an issue where I had a 480V 3Ph 2HP Powerflex 525 blow up. Upon further inspection, we noticed that 10 other VFD's had also been taken out in the process. There were no internal power surges in the plant (we have facilities in place at the switch gear to protect over/undervoltage, loss of phase situations, etc), but I believe that one drive in particular blew its caps up and that surged the panel, taking out other VFD's. Upon troubleshooting, no phase-to-phase, dead short other ground fault issues were found in any part of the panel or any of the field devices.
The panel has 28 identical 525's that are zero-stacked (aka literally side-by-side mounted across the DIN rails), are individually protected by Eaton 4-6.3A adjustable MCCB's and all are fed from a 200 amp disconnect
My question is, what can be done to prevent one VFD explosion from taking out others? I've heard that using J-class fuse blocks instead of MCCB's will help as them blowing may prevent a cap-exploding VFD panel surge from passing onto neighboring drives. I don't want to create nuisance blown fuses by just replacing the MCCB's with fuses but I need to do something different. I was thinking about putting fuses upstream of the MCCB's, but rating them at some arbitrary value above the MCCB limits. Does this sound reasonable?
One caveat: I am making an assumption here that the one VFD failing was the cause of the others, so I'd also like hear any other ideas that could have caused it.
Thanks!