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Mechanical Engineer here trying to wrap my head around electrical question. I have a 1000HP, 600VAC VFD driven motor. I understand the VFD induced bearing currents fairly well, the part I'm having trouble wrapping my head around is related to a possible safety issue. Lets for now assume...

I was curious if anybody has had any experience with the spring loaded shaft grounding brushes affecting the dynamic balance of a fan/motor assembly. Customer has requested following: "AMCA standard 204-96, exceeding category BV-5, to meet or exceed an equivalent Grade G.55, producing a...

Getting back to the main topic of this question, any suggestions out there for a good book on Intro to EMI?

Thanks for the input Skosgurra, very helpful. Perhaps a little more detail would help. I'm not exactly looking to certify an item to bring it to market. I'll be testing with an AC induction motor hooked up to a VFD and I'm more looking to see how our product alters the EMI output from the...

I was wondering if anybody on here might suggest a great introduction to EMI book to read as I've been tasked with setting up and running an EMI test. I see a lot of books out there on EMI as related to printed circuit boards, this is not what I'm looking for. The test I'll be setting up is...

I was wondering if there was a way to get Agar (or Agarose) to break down once it's already gelled. I'm not apposed to mixing something into the Agar gel as long as it's not highly toxic or explosive. Bear with me here as I'm actually mechanical eng background, so this is new ground for me...

I thought about closing it off and then doing a leak down test to see how much time it took to drop X number of psi. I like the assumption that if the leak is small enough you can approximate it as laminar flow. So think I'm gonna do the following: 1) Make sure to set the valve I plumbed in...

Ok, have a tank of Argon which I am using to posotively pressurize a small container. Positive pressure is only to keep outside air out of container ensuring my small container is pretty much all argon in it. What I'm trying to figure out is how long my tank will last. I know I need to...

My very simplified understanding of the answer to my question is that you must change the amount of Power used. You can do this by either reducing the work done or by reducing the speed you are doing it at. In the end the process requirements for the conveyor line dictate the amount of...

I think this makes more sense when you mentioned that mechanical means gives less speed but more torque, but going to a VFD will give less speed, but same Torque output by motor. I was going through all the mechanical equations and what happens when you simply replace gearbox with motor running...

Trying to understand how VFD's save you money, and I've seen people throw around that a x% reduction in speed is equal x% cubed in energy reduction. From what I can tell this is only true for pumping or air handling type applications where speed and flow are roughly a 1:1 ratio but speed to...

I was wondering if anybody has any good information related to the costs carrying costs related to cleaning/stripping powder coating hooks. I'm not so much interested in the capital equipment costs for burn off ovens or stripping tanks etc. I am more interested in how much does it cost to...

KllrWolf: We've tried conductive paints and have found a colloidal silver paint that seems to work ok. That in itself only prolongs issue until we see the rusting. Perhaps it's not an ideal solution because we are seeing Galvanic corrosion between the carbon steel shaft and silver particles...

Can't do vacuum. Stainless and chrome have been our go to choices when our customer asks what to make the surface out of. 90% of the time surface is just plain old carbon steel and we can't get them to change that.

Well, thanks for all the responses even though I know I'm being pretty vague. I'll try to give a better description here of what I'm battling: As shaft surface abrades it rusts, so loses electrical conductivity which is necessary for product to function. Cleaning shaft periodically solves...

Fair enough Compositepro. I'm adhering it to a shaft, so needs to be flexible to wrap around that. Most likely steel shaft, but may be other metals at times so it needs to stick/adhere to that. I started this out with thin because I don't have a lot of normal force being applied to abrade...

Ok, was thinking along the lines of an adhesive backed tape. Only reason I want thin is so that I can slowly abrade through it, eventually abrading all the way through it. Might not have to be tape, could be paint on coating? I know it's a little vague, but abrading through the tape/coating...

I'm looking for a tape that is very thin. Thinner the better as I am actually looking to have it wear out through mechanical abrasion. Any suggestions?

I have micro-fiber material sliding over a surface. Can't divulge exactly what micro-fiber material is, but lets just say the material is extremely hard (hint). As it abrades the surface it's riding on, I get an iron oxide layer building up. It seems to wear the surface and expose fresh...

1gibson: Meant DE thrust bearing supporting the weight of the rotor. Typed a letter wrong there (typed m, meant r). When I sketch my free body diagrams with the thrust bearing in either the DE or the NDE, the bearing is in compression by the weight of the Rotor. electricpete: I can see...