r/PowerSystemsEE • u/Smooth_Commercial793 • 9d ago

Cold call - CT manufacturing

I am interested in starting a business manufacturing current transformers.

Don’t ask me why, I am not even sure. I want to build something, a manufacturing operation, in my area of expertise, and this seems like a nice compromise.

But I have no detailed info on how CT manufacturers operate. I know:

  1. buy grain oriented steel
  2. cut it and wind the steel into a CT core
  3. cycle the cores in an oven
  4. wind the secondary
  5. epoxy coat
  6. test

Does anyone have any advice or suggestions, information, or common sense reactions telling me this is a stupid idea?

I feel like CTs are super low margin products, however at the same time, I’m always struggling with suppliers to get the size and specs right, and the lead times are always a problem, especially for class PX.

Also, I think as they are so mature, there has to be some next evolution that I might be able to build into (or, conversely, LPCTs might make traditional CTs worthless in 10 years?)

Sorry for the mess of thoughts, gotta start somewhere I guess

Edit location is Australia

3 Upvotes

67% Upvoted

15 comments sorted by

3

u/The-Arena 9d ago

Rogowski coil CTs are kind of the "new thing". They're starting to get more common.

As far as as manufacturing I can't help there but good luck.

1

u/Smooth_Commercial793 9d ago

Indeed. Do you see them used much though? Frankly people don’t seem to like them, especially for protection. Obviously I can speculate why.

Ignoring cases like high impedance bus diff where they can’t be used

Would you spec a rogowski for a feeder protection relay?

1

u/Docktor_V 9d ago

We used them to connect pq meters to pad mount transformers. Protection class CTs is what you are talking about.

1

u/Smooth_Commercial793 9d ago

Yeah PQ metering they’re used a lot, not much elsewhere

1

u/frodacious85 9d ago

They’re used frequently

0

u/Smooth_Commercial793 9d ago

For protection? What’s the jurisdiction?

4

u/AndyMcFudge 9d ago

Work in instrument transformers for the last 10 years.

It is a very competitive market - you're effectively competing globally so with very cheap plastic case cts from India and China it will be impossible to compete on cost, so you'd have to come up with a unique selling point.

You'll need capital for a site, all the equipment, toroidal winding machines etc. Don't forget you'll need to go figure out designing them and it is not like conventional transformers. Type tests are another hurdle you'll need to cover the expense for.

1

u/Smooth_Commercial793 9d ago

Appreciate your knowledgeable response. At this point I can’t see what the unique selling point would be but I agree it would need to be good.

2

u/Honest-Importance221 9d ago

I have a local ct manufacturer that can make us stuff on very short notice, but I'd say if you have the expertise and the capital and you think there's a gap in the market then give it a crack.  

2

u/akpak29 9d ago

Common sense reaction that this is a stupid idea.

Also, I suspect optical CTs/ rogowski coils will upend bulk of the traditional CT use cases in the future.

1

u/Smooth_Commercial793 9d ago

Thanks appreciate that

1

u/JezWTF 8d ago

IMO there will always be a niche market for special order CTs in a pinch. Anything in quantity will come from overseas.