480V vs 460V primary on step down controls transformer

[SD450s]

I have an exhaust air handler on a data center. long story short, the fuses on the primary side of controls transformer were blowing so we determined we had a bad transformer. Old transformer was 1500VA 460:120 square d transformer (9070T1500D20). Had a time crunch so I got what I though was the same square d 1500VA transformer but realized it was slightly different (9070T1500D1). New transformer has separate taps for 460V and 480V. We have a 480V system.

Square d customer service says to not use the 460V variety on a 480V system. I was always under the impression that a 460V transformer was a nominal and would cover up to 480V. Trying to determine if we should go through and change all of the old 460V transformers to 480V transformers. Anyone else have experience with this?

 

[don_resqcapt19]

With motors, the nameplate voltage for a motor intended to be connected to a 480 volt system will be 460.
A bit different with the transformer as the secondary voltage is directly related to the primary voltage.
In your case I don't think it makes much real world difference because if you put 480 volts on the primary of a 460/120 volt transformer, the secondary voltage will be about 125 volts. Should not present a problem.

 

[ruxton.stanislaw]

Product data sheets:

 

[ptonsparky]

I have an exhaust air handler on a data center. long story short, the fuses on the primary side of controls transformer were blowing so we determined we had a bad transformer. Old transformer was 1500VA 460:120 square d transformer (9070T1500D20). Had a time crunch so I got what I though was the same square d 1500VA transformer but realized it was slightly different (9070T1500D1). New transformer has separate taps for 460V and 480V. We have a 480V system.

Square d customer service says to not use the 460V variety on a 480V system. I was always under the impression that a 460V transformer was a nominal and would cover up to 480V. Trying to determine if we should go through and change all of the old 460V transformers to 480V transformers. Anyone else have experience with this?

Have replacement on hand and change if and when they fail. Make sure your primary fuses are correctly sized.

 

[ruxton.stanislaw]

If they told you explicitly not to use it, I am interpreting that 460V could be intended for the upper end of 416/240 services. E.g. I recall BigCliveDotCom saying that on his island, he sees his 240V service as high as 260 - 270V at times (around 460V three phase). More anecdotal, but I have personally seen AC adaptors specifically rated for 260V (as opposed to 240 or 250V) in those other parts of the world. Even though it is not technically proper, you might get away with it just fine if your 480 service is running cold. However, if it is exceeding 500V consistently, then the transformer could burn out one day.

I notice that is already a pretty small transformer. You could buy a super small buck boost transformer to put ahead of it for peace of mind.