Need Clean Electricity

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eeee

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I have an expensive piece of equipment that is feared not to have clean enough electricity and have been tasked to make sure that this is not the problem. It may be the software or some other part of the machine, but this has supposedly been ruled out. Now it is thought it may be the electricity. This same problem has occured at a different location, but has a small difference. The equipment is a prototype I think.

I know there is test equipment out there, but am limited to the equipment I have, although I may be able to get some more if required-outside chance.

I am going to put an oscilliscope on it and compare this reading with what a known good building should read.

Any better ideas out there?
 
Re: Need Clean Electricity

Filters were added on the machine at the other site, but the problem persists. It is expected it is not a problem with the power since filters were added at the site which had the most unclean electricity, yet this machine behaves the best, although it still has the problem.

The problem is still unkown, so it is still possible that the power was not cleaned up enough using the filters at the other site.
 
Re: Need Clean Electricity

Let me suggest that you first test the incoming power supply with your expensive equipment disconnected. You'll need to know if it is your equipment that is the cause of the problems. If the "prototype" is causing its own power quality problems, then you are going to have to send it back for further development.

The information you need to learn from your tests (both with and without your expensive equipment on-line) is the harmonic content. An oscilloscope can show you the appearance of the voltage and current waveforms, but it should also tell you the amount of harmonic distortion.

What you really need to find out, however, would come from the creators of this expensive equipment. You need to know its tolerance for harmonic distortion; you need to know how clean is "clean enough." I think that that is the essence of Bryan's question.

It does not surprise me that the filter did not work. You don't yet know what type of filter you need. You can't create a useful filter without knowing what "bad stuff" is in the incoming signal, because it is that "bad stuff" that you want to filter out. But you can't create a filter that would keep the "bad stuff" away from your expensive equipment, if it is the equipment itself that is creating the "bad stuff."
 
Re: Need Clean Electricity

eeee,

What is the nature of this equipment? Some electronic equipment must be grounded and shielded properly for proper operation. I recall a case where a system was measuring nanoAmps. We grounded the system properly and started measuring picoAmps.

A scope should show spikes and gross harmonic content. A harmonic analyzer would be required to actually measure the harmonics. Even if you can see distortion with the scope, that may not be the problem.

[ September 27, 2005, 11:11 AM: Message edited by: rattus ]
 
Re: Need Clean Electricity

What you need to do is find out where the "problem" is located. I have found out over the years to work in reverse; that is to eliminate possible "sources" of the unclean electricity. Properly analyze your incoming power using a power analyzer. It will record amps, volts, kw, kva, harmonics, among a few. This will either point to the incoming power or rule it out!
 
Re: Need Clean Electricity

It looks like we are going to let the owners of the machine figure it out (this decision is not yet final) since the probability is too low that it could be a facility power problem since the facility with bad power statistics has a better operating machine. But as anomolies go, they are unpredictable.

It is assumed that strategically it would be better to let the owners of the machine try again to resolve it, rather than waste our resources at this point. They usually have resolved complicated anaomolies in the past eventually and found it is with the machine, even though they feel somewhat confident it is not there problem. It is a business case decision that probabilistically, it is the machine so the machine failure issue must be revisited again. Can't throw a bunch of money and resources at a 1 in 1,000 chance it seems. The issue of it being bad power is too much an ulikely case based on some individuals present judgement.

I liked the issue of reverse engineering it. I will suggest that to the owners of the machine as well as providing some other hints.

I assume the last responder is indicating that a power analyzer is different than a harmonic analyzer and will analyze harmonics as good as a harmonic analyzer.
 
Re: Need Clean Electricity

Originally posted by eeee:
.

I assume the last responder is indicating that a power analyzer is different than a harmonic analyzer and will analyze harmonics as good as a harmonic analyzer.
Click to expand...
Nah, I am just saying that a scope alone will not do it. I would still like to know what this machine does.
 
Re: Need Clean Electricity

I think he means it is probably a software problem, if not that a firmware problem, then it would be a hardware problem or cockpit trouble. It is probably not the AC source.
 
Re: Need Clean Electricity

A scope for intermittent problem? I do not know anyone who can watch one for 24 hours a day and draw the pattern when it goes south. It would take a PQ analyzer.


eeee, you have done the right thing and put the monkey on the manufactures back. At the most you could use an isolation transformer to clean things up, but let the manufacture foot the bill for thier garbage.
 
Re: Need Clean Electricity

Yes,

I passed helpfull information to the manufacturer, but hope it is used. I have disovered it is not the time to tackle the problem myself unless specifically asked by the manufactuer. I am fairly confident that this will be the course of action that will be taken.

It would be interesting to know what a PQ analyzer is?

It would also be interesting to know how the isolation transformer would be used to clean things up. I assume it would be used in combination with a filter that I would need to design so as to isolate power networks?
 
Re: Need Clean Electricity

I don't want to sound like there isn't something that can be done to remedy the problem or that it shouldn't be looked at. But. Almost every time I've had to deal with equipment that wouldn't work correctly because of "noise" problems, the problem was the equipment, not the electricity.

I say almost every time because there must have been once where it was the electricity but actually I can't think of a time where it was.
 
Re: Need Clean Electricity

With equipment like that it could be your power from the power source not correct. Say your neutrals and grounds are tie together in a sub panel and you feed them though conduit, you could get EMF in the sysytem.
Jim
 
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