Transformer substitution

[wirebender]

Are there any problems with using a 480V to 208V transformer below its rating?

For instance, using a 112.5 KVA in place of a 75 KVA to feed a 225A panel?

 

[GoldDigger]

Are there any problems with using a 480V to 208V transformer below its rating?

For instance, using a 112.5 KVA in place of a 75 KVA to feed a 225A panel?

1. It takes up more space.
2. It may cost more, but I am guessing you have one already?
3. More significant, its turn-on transient current (inrush) will be higher and its idling current and the resulting iron and copper losses will be higher. That may not be enough of a difference to influence your choice though. And the operating losses may actually be lower.
4. Higher available fault current at the secondary, if your OCPD, etc. is close to its AIC limit.

 

[wirebender]

1. It takes up more space.
2. It may cost more, but I am guessing you have one already?
3. More significant, its turn-on transient current (inrush) will be higher and its idling current and the resulting iron and copper losses will be higher. That may not be enough of a difference to influence your choice though. And the operating losses may actually be lower.
4. Higher available fault current at the secondary, if your OCPD, etc. is close to its AIC limit.

Yes, we already have them.
Revamping a building, used to be like a large grocery, had tons of power. We will only be using 600A. The place has been scavenged but they left the transformers.
We are thinking of using them.