480/240 volt single phase transformer

[electricman8something]

I hooked up a transformer thinking I needed 240 volts but as it turned out I needed 208 Volts single phase. Because I did not have a 208 single phase available I incorporated a buck boost. I hooked the single phase transformer primary to 480 V H1 to L1, H4 to L2, H2 & H3. On the secondary side I connected X2&X3 to ground. my output was 240 Volts.Then I hooked up the buck boost as follows output of 10KVA connected to H4 and X1 , X2&X3 Connected, H3 & H2 connected, H1 & X4 Connected to output and H4 connected to other output. Loads seem all right but transformer is warm. Warmer on top of transformer then on sides. Transformers get warm someone did temp check and said it was 130 degrees

 

[mull982]

I hooked up a transformer thinking I needed 240 volts but as it turned out I needed 208 Volts single phase. Because I did not have a 208 single phase available I incorporated a buck boost. I hooked the single phase transformer primary to 480 V H1 to L1, H4 to L2, H2 & H3. On the secondary side I connected X2&X3 to ground. my output was 240 Volts.Then I hooked up the buck boost as follows output of 10KVA connected to H4 and X1 , X2&X3 Connected, H3 & H2 connected, H1 & X4 Connected to output and H4 connected to other output. Loads seem all right but transformer is warm. Warmer on top of transformer then on sides. Transformers get warm someone did temp check and said it was 130 degrees

Your description is hard to visualize, can you post a schematic?

 

[charlie b]

Loads seem all right but transformer is warm. Warmer on top of transformer then on sides. Transformers get warm someone did temp check and said it was 130 degrees

That would not concern me. I would expect any device to be hotter on the top, since heat rises, and a rise of 130 degrees should not be beyond the transformer's rating. Did you verify that your setup provided the correct voltage? Can you check the transformer ratings, to verify that a 130 degree rise is acceptable?

 

[guschash]

I am not sure if you can 208 on a buck/boost transformer with 480/240 primary,single phase. I'm looking in a book of transformers and the table selection for 480/240 single phase doesn't show that you can get 208. If i'm reading your thread correctly, you want to get 208 from 480 primary with a buck/boost x-former.

 

[Volta]

I am not sure if you can 208 on a buck/boost transformer with 480/240 primary,single phase. I'm looking in a book of transformers and the table selection for 480/240 single phase doesn't show that you can get 208. If i'm reading your thread correctly, you want to get 208 from 480 primary with a buck/boost x-former.

He has two transformers, one step-down to 240, one auto to buck.

 

[guschash]

What is your output voltage?

 

[jim dungar]

Loads seem all right but transformer is warm. Warmer on top of transformer then on sides. Transformers get warm someone did temp check and said it was 130 degrees

I would not be surprised to find the case of a small buck-boost transformer to be too hot to touch. These sand-resin filled transformers are usually rated for a full load "internal" temperature rise of 115?C above a 30?C ambient.