Autotransformer ratings

[thinker]

We have an autotransformer (3 phase/Wye) with taps marked
230V,380V,460V,575V on each phase coil. The name plate
shows 175 KVA. Please advise, what this KVA is related to?
Is this a rated capacity at any of voltage levels? How to
determine a maximum load in step-down configuration?

 

[tgott]

As I understand your question- yes 175 kVA is the rated capacity at each of the voltages listed. The current will change for the various voltages. For example, at 230V, current will be 439A and at 575V current will be 176A. For normal operation, the kVA rating is the maximum load that should be placed onto a transformer.

 

[thinker]

tgott:
thanks for the prompt response.

 

[busbar]

Wouldn't the maximum rating be determined by current, similar to the FCAN and FCBN ratings in a 2-winding dry-type? If the label isn’t specific, it may make a phone call a good investment.