Imaging Equipment Failure - EMF Power Quality...IDK!
Imaging Equipment Failure - EMF Power Quality...IDK!
(OP)
Dear Experts,
I need some insight on this. I have an ultrasonic machine (attached cutsheet) that is showing false images. This is becoming very problematic. I hired an EMF company they returned and some power quality issue, he was 100% sure and had gray hair, so I believed him. I hired a PQ company and they found some high frequency noise on the ground. I bought a hospital grade http://www.clary.com/products/instrumentation/s150... double conversion UPS becuase they said it would take forever to find the motor contributing to the noise (also 24x7 facility)
Could a Power Quality event get through the UPS I bought? It is a double conversion unit?
Any other thoughts...
I need some insight on this. I have an ultrasonic machine (attached cutsheet) that is showing false images. This is becoming very problematic. I hired an EMF company they returned and some power quality issue, he was 100% sure and had gray hair, so I believed him. I hired a PQ company and they found some high frequency noise on the ground. I bought a hospital grade http://www.clary.com/products/instrumentation/s150... double conversion UPS becuase they said it would take forever to find the motor contributing to the noise (also 24x7 facility)
Could a Power Quality event get through the UPS I bought? It is a double conversion unit?
Any other thoughts...






RE: Imaging Equipment Failure - EMF Power Quality...IDK!
Streaks? Snow? Distortion? Mirror images?
Did the picture fail in the same way before and after you put the UPS there?
I had the same problem with a unit in a prenatal application. It wasn't hard at all to find the fan with VFD that caused the problem. Used an EMI sniffer and traced the cable.
Other case, HF knife for cutting and stopping bleeding. Just changed the PCC and put an extra ground wire (there was a terminal for that).
Third case, wobbling picture (this was a CRT unit) caused by nearby train starting. Not much to do. Some success with mu-metal screen.
Gunnar Englund
www.gke.org
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Half full - Half empty? I don't mind. It's what in it that counts.
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
Supposedly they show the same disturbances but will get photos and upload the before and after uPS disturbances.
EMI sniffer? Do you have an example and how hard would that be to use or do I need to hire somebody?
I thought an online Ups would have solved it.
The hf knife you mentioned changing the pcc, isn't that what a dual conversion Ups does?
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
The HF knife is a surgeon thing that is used to cut tissues with minimal bleeding. It emits rather strong HF energy and is often a source of interference. It has nothing to do with "cutting up" the grid, but that's a nice thought.
If your UPS isn't either a sine-wave output or a very well filtered UPS, you may end up with as much EMI from the supposedly clean grid as you had before. You need to really read the fineprint and also remember that the "reject", i.e. the noise that has been filtered away shall be taken care of in an orderly way and not dumped to your PE. Dumping noise onto the PE is like dumping the kitchen sink onto the floor. Only, you don't see the garbage when it is electrical. But your equipment senses it.
All for now. Wait for Keith.
Gunnar Englund
www.gke.org
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Half full - Half empty? I don't mind. It's what in it that counts.
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
Skogsgurra; This is what Skogs is referring to.
http://www.credencetech.com/scanem.html
I think you'd want the CTK010 without the cables.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
Except it was supposed to be:
living2learn; This is what Skogs is referring to.
Keith Cress
kcress - http://www.flaminsystems.com
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
In the meantime I thought I was ordering a solution that would solve my power quality problems. The ups is Fully Regenerative; True On-Line; Low Distortion Sinewave Output style http://www.clary.com/products/instrumentation/s150... but I guess that didn't solve this problem.
skogs - what should you do with all the garbage you filtered out? If you don't want it on your PE (protecive earth?) then where do you want it to go?
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
Instead, so called five-wire systems are used. They separate PE and N and use N instead of PE-N to drain filters. N is allowed to carry current - PE is not, unless there is a fault that needs to be cleared.
That is part of the solution, but keeping PE and N separated is a problem and I have been to hospitals where the local installation firms didn't know how important it is to maintain the five-wire system a five and not a four wire system, which it turns into if you inadvertently connect PE and N somewhere.
It is not an easy situation and you need to keep the system under constant surveillance, take part in buying decisions (to make sure the new equipment doesn't violate the five-wire system), educate the sparkies and inspect every new installation.
There are a few drives and perhaps UPS with what I once coined "intrinsic EMC" and they can be used in hospitals without any extra precautions. Not sure if they are available in the US.
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
For completeness: T (Terre, GND) N (Neutre, N) says how your system is connected to ground at the feeding end and at the consuming end. And C or S says how PE and N are used.
There are also IT systems, where the feeding end is isolated (Isolée) and there is a local ground (Terre) at the consuming end. Used a lot in process industry. And in Norway.
In the US, you can find TT systems. There the feeding end has one ground connection (Terre, again) and the consuming end has its own ground (Terre, of course).
End of crash course.
Gunnar Englund
www.gke.org
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Half full - Half empty? I don't mind. It's what in it that counts.
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
The first test I wanted to perfom at this location was to test the resistance between Nuetral and Ground at the transformer by removing the neutral disconnect link. Unfortunatly the 12kV circuit breaker feeding this transformer is broken and scheduled for replacement in a few months, therefore no test allowed. Do you know of another way to test multiple N-G bond connections without turning off the service (90% of loads are 4w+g)?
Funny story, met an electrician the other day who argued extremely with me that anytime you see the white wire (neutral) you connect the green (earth) to it...this is at a huge site and we have found so far over 30 connections!!
Also have attached the images that show the errors...I am starting to lean towards RF as the cause of problems
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
If you have any influence, I think you have a tough job before you. Getting rid of all that isn't easy.
The Chauvin-Arnoux ground resistance tester works well in situations like these. http://uk.rs-online.com/web/p/earth-ground-resista... It makes it relatively easy to find unwanted connections. But it doesn't eliminate the need to plan and think.
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
As a test we got a slab of meat and a cotterizer and observed the 1 to 1 correspodence on the image distortions, as this test set-up was moved up and down the hallways."Safe" operating distances were established.
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
Bill
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"Why not the best?"
Jimmy Carter
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
RE: Imaging Equipment Failure - EMF Power Quality...IDK!
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.