[evoluzione]

Dear forum members,

I have a dilemma that I need to solve ASAP

Oven specs are:

A.C. V230 3 Frequency
Max power
*Medium consum/hour Connecting cable

22 8 8

combined

H07RN-F 4x6 mm2 (V230 3)

Prover feeding
A.C.V 230 1 N 50/60 Hz
Max power 1.5 kW *Medium consum/hour 0.8 kWh

Building is 208v 3 phase. My issue is how do I get to 240v without getting into an ordeal with permitting and cost?

Is there anything that can be done?

It is crucial as this is the main piece of equipment...

[ma0641]

The only way to get 230VAC from a 208 is to use a transformer. They are not inexpensive. Your heating side will run fine on 3 phase 208, just will heat slower. The motor will not operate at peak efficiently but will run. 10% is the usual max differential. 230VAC -10%= 207VAC. Kind of like a brownout in the summer. If this is a planned long term install, get a transformer.

[evoluzione]

Thank you for your quick response.

Do you have any examples of what kind of transformer I will need?

How big are they, and how do I have to go about getting it installed?

Thanks

[smoothy]

Also consider the line frequency in Italy is 50hz and in the USA its 60hz This may be an issue for certain things like mechanical timers..

[evoluzione]

Hi smoothy,

The prover should be OK as it's the only one that mentions hz. And it is both 50/60hz. The timer on the oven is electrical rather than mechanical. This shouldn't affect it right?

[smoothy]

From what you said I think that part is fine..

[evoluzione]

also, what kind of KVA would I be looking for?

oven is A.C. V 240 3ph 60Hz

and 2X this figure: MAX POWER each deck: 10.1kW (24.4 amps)
*Average power consumpt./hour 5.1 kWh (12.2 amps)

I also have a mixer that is 220v (US company) and three phase...

Any ideas?

[smoothy]

Those are a bit beyond my background and experience... I'm a Degreed Electronic Engineer.. not an Electrical Engineer or Electrician so there are a lot of gaps in my knowledge of this field (particularly three phase stuff). One of these other guys can answer that

[evoluzione]

At the moment the electrician is confident that boosters will be enough, since the step up from 208 to 240 is minimal. I am hoping for this too...

[hfcarson]

The transformer connection scheme is called a "buck - boost" connection. A few small single phase transformers and you're good to go...
The transformer companies that sell these have charts to help you size them - Buck and Boost Transformer Calculator - Schneider Electric United States is from Square D although it sounds like your electrician is way ahead of me on this one...
If I could see your equipment I would not be surprised to find that it would operate just fine at any voltage between 208 and 240...

[evoluzione]

Sadly, this is the misconception and the reason why the electrician who drew up the plans didn't consider this. Being an italian convection oven, it is important for the oven to be able to reach peak temperature within a short while (we are talking less then 40 minutes). The oven has two chambers, each with separate electrical connections, and rated at the specs posted above.
A 15% difference is too much for it, and I know for a fact, that running it at 208, will mean that not only will it take considerably more time to heat up, but as soon as you open the doors temperature will fall and you will lose productivity. Furthermore, the oven will be straining to reach the set temps, and so consume more because of this.

I am glad I noticed this now and not the day I turn on the oven...

Now I hope that the transformers are of a reasonable price...