Westinghouse 7000:5A Current Transformers 2

[jpwren]

I am trying to find information on a few Westinghouse 7000:5A CT's, but am having no luck. If anyone could tell me where to get nameplate data from old Westinghouse products or even be able to tell me information on these particular CT's such as ratings, accuracy class, excitation curve, etc. I would be greatly appreciative.

Thanks,
Justin

 

[busbar]

That ratio is not ANSI-standard for single or multi-ratio units, making it likely a special-order component. You may have luck comparing measured characteristics to similar currently listed in catalog data. The overall weight, saturation voltage and ratio {it could be mislabeled} will probably have the largest effects for ratings comparison.

 

[scottf]

I would try ABB, as they bought all of the Westinghouse T&D operations in the US. What type of CT is it? I might be able to point you to the correct factory.

 

[busbar]

Above 6000A type RCF at

http://www.abb.com/global/abbzh/abbzh289.nsf/0/af41de45f90f0d85c1256c480057423a

 

[jbartos]

Suggestion: Contact the ABB tech support for more info since the larger ratio CTs may have doughnut style of rectangular split core style

 

[jpwren]

Thank you all for the replies. It was actually ABB who was needing the information and I was trying to gather it for them. They were saying the same thing that busbar said about them not being a standard ratio for MV switchgear and they were needing more information on our existing ones, which of course I couldn't find any information on or get access to. We have decided to replace the 7000:5A CT's with 3500:2.5A CT's which are more readily available from what I've been told.

 

[busbar]

Exactly what is wrong with the existing CTs?

 

[jpwren]

Nothing that I know of. We are just replacing/upgrading some equipment and the CT's are part of some equipment getting replaced. Please keep in mind that I'm mechanical in nature so all of this electrical stuff is a little over my head!

 

[jbartos]

Comments: CTs insulation deteriorates in time just like any other electrical equipment insulation. This will impact the CT accuracy.

 

[busbar]

Please, please, please don’t change ‘em out because some salesman suggests it. He’s just after a bit of quick sales volume. If you have been led to believe that 7000:5s are perilously non-mainstream and should be discarded for that reason, 3500:2.5s will throw an even semi-conscious, slightly qualified test technician into convulsions, while making equally effective door stops or canoe anchors.

ABB Pinetops can and regularly does make a good product, but parent-company droids will sell anything. Personally, if for whatever reason push comes to shove, you will likely be far better off buying 8000:5s and stripping off 200 turns from each.

If there are any significant concerns, spend a little maintenance money {or project funds} on having the existing CTs given routine, in-situ tests. Very likely they are in good shape, or if not, the associated gear is crumbling around them, and an odd CT ratio is the least of your problems.

 

[jbartos]

Suggestion: According to Westinghouse Catalog 55-000 10th Edition, 1991/1992 the 7000:5A CT appears to be non-standard. Medium voltage swithchgear used to have 4000:5A standard size and 5000:5A CT, for low voltage buses, standard size.

 

[jbartos]

Suggestion: Check with companies that are replacing them, e.g.

https://www.kuhlman.com/navigation.asp?pathIDs=10,1645&selectedID=1645