Recent content by mpparent

Here...try this link: https://www.vertiv.com/49f28b/globalassets/products/critical-power/uninterruptible-power-supplies-ups/liebert-nxl-operation-and-maintenance-manual_00.pdf Page 57... Mike Mike

Old motor nameplates, I believe, were Div 1 capable (going by memory, so double check me on that). However, as described previously, check w/ your process engineer to ensure Group D is still applicable. Often-times in the plant where I worked, process chemicals were changed routinely and motor...

Hi cuky... Noted. However, I think the OP was referring to LV breakers. While the standard is old, the testing X/Rs haven't changed to my knowledge. Mike Mike

Screenshot from IEEE 551: Mike

IEEE C37.010-1999 gives: 1) Low value ~9 2) Medium value ~19 3) High value ~25 Mike Mike

This site has some good information: https://www.northamericaphaseconverters.com/resources-assistance/rotary-phase-converter-faq/ Mike Mike

Thanks Keith...learn something new every day. Mike Mike

Do you have a specific application? Mike Mike

Potential cable/wiring withstand issues... Mike Mike

Well, IEEE 493 may provide some insight. Failure rates for bus duct is .0003 failures/yr. Mike Mike

Often-times if you ask, the manufacturer's have the harmonic spectrum for their drives. Can you model the system using SKM, Easypower, etc. and see what the overall harmonic spectrum is? That should get you fairly close. Also, IEEE 519, IMHO, is often misapplied. Furthermore, I have seen current...

It's also good to periodically check-in with your customers. Tell them about new tech, etc. A little face time goes a long way. Mike Mike

Incidentally, We were reading unbalanced currents on both the line and load sides of the VFD. That can't be good... (I'm not sure of the % of unbalance. I'll know more in a couple of weeks...the monitoring period) Mike

waross, The process owner really isn't sure if the existing motor is adequate. Else, we would have certainly done that. Mike

All, I have a motor (of which I do not have a nameplate to verify HP rating), which belongs to a process. The process owner wants to purchase a new motor, but with no nameplate, we are unsure of what to purchase (a new motor was purchased at one point and it turned out to be wrong). The motor...