petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- Semi-retired engineer
So I have an application for 120 V 3 phase delta power. I know it is a little unusual and I figure I will have to use three single phase transformers banked together because probably no one makes a 3 phase unit like this, at least off the shelf.
So I was thinking about this. A nine kVA 3 phase transformer would be 10.8 Amps primary current, and the primary OCPD could be 250% of that number.
My first thought was the three transformer bank could use the same arrangement for OCPD.
However, I thought about it some more, and came to the conclusion that one single phase transformer is rated at 6.25 A primary current, so even though it is wired as a three phase bank, it would need to have OCPD as if it is a single phase transformer.
Any comments.
So I was thinking about this. A nine kVA 3 phase transformer would be 10.8 Amps primary current, and the primary OCPD could be 250% of that number.
My first thought was the three transformer bank could use the same arrangement for OCPD.
However, I thought about it some more, and came to the conclusion that one single phase transformer is rated at 6.25 A primary current, so even though it is wired as a three phase bank, it would need to have OCPD as if it is a single phase transformer.
Any comments.
