USA to European Transformer Calculation

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mrmike99

Member
Location
chicago
Hello,

We have a restaurant and a high temperature double deck pizza oven out of the UK, made in Sweden.

Each deck is rated for european 3 phase 400v, uses 18.5 amps on each oven, 12.6 kw power each oven, 25.2 kw total.

The power in the building is an older 240v 3 phase delta with a high b leg.

We believe a 25 kva transformer would max it out and need to add a 20% cushion putting it just over 30 kva

and need to step up to a 45 kva.

We believe we need a 45 kva delta to wye transformer with neutral on wye side + ground going to the oven with

separate cut off switches with 20 amp fuses from the transformer.

We also believe we need a breaker over 65 amps in the supply breaker panel to feed the transformer.

Can we get a second opinion? do you concur?

Thanks for your input,

Mike
 
Tony S

Tony S

Senior Member
Location
Resting under the Major Oak UK
400 or 433V

400 or 433V

I would check it is actually rated at 400V. The UK uses 433/250V despite anything the IET and IEC say.

The IEC changed the unified voltage to 400V, the electricity supply regulating bodies change the allowable deviation to -6% +10%. Basically many countries, not just the UK ignored the IEC.
 
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mrmike99

Member
Location
chicago
Follow up

Follow up

Yes, we need a neutral from the wye side as well as ground to the oven decks.

Yes, the 400v 3n comes directly from the name plate. It is a Bakepartner Pizzamaster PM742 made in Sweden. Maximum temperature 932 farenheit! The name plate also lists it as 50/60hz not just 50hz.

Yes, the 20% cushion suggested may now be an overkill. It not a motor, so I would think we might be fine with the 30kva. The person suggesting it was from Tempco Transformers and said it was code.

Does anyone know if such a code exists?

Tempco stocks them, other transformer manufacturers have to custom build them. Not sure why they would not be more common with European machinery importing. Tempco sells the 45kva for $2400 + $200 shipping. The 30kva is $1930 + $350 shipping (why more to ship I have no idea other than profit). Still pretty reasonable for new vs other manufacturers.

Thanks for the surplus link, we asked for a price quote.

Anyone have another line on a used one?

Another transformer set up with a more common transformer?

Thanks for everyone's help.
 
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mrmike99

Member
Location
chicago
380v wye side?

380v wye side?

It was also suggested that an older 380v wye side transformer would also power the 400v oven.

Would that be true?
 
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