3Ǿ & Oven

Little Bill

Little Bill

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Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
A business is taking on some more equipment. The equipment came from a shop that has 3Ǿ power. Their place only has single Ǿ. There is only two pieces of equipment that needs 3Ǿ. One is an air compressor and I plan on an RPC for that. However, there is an oven that operates on 480V 3Ǿ. Currently, in the place where it is, there is a transformer taking 240V to 480V. I'm not sure how to get power for the oven with a RPC. I think their new service will be either 208V, or 240V. So I think the oven would work, but take longer to heat.
Also thought about changing the elements to single Ǿ.

The business doesn't want the expense of having 3Ǿ brought in. So what are your thoughts on powering the oven? Can you use an RPC for a static load like the oven? For the record, the RPC I would get would be for both the air compressor and oven. They would only use one of them at a time.
 
Do you have a schematic for the oven, or can you deduce one from opening it up?

Depending on what loads are inside, you may be able to rewire it for single phase without much trouble. For example, the only load on all 3 phases might be 2 or more 2-wire heating elements, connected in a delta fashion. In which case it should be possible to rewire those heating elements to all be supplied by the same phase, so the oven only needs 480V single phase.

Even if it has a true 3 phase load in it like a 3 phase fan motor, the bulk of the load should be the heating elements. So if you can rewire those single phase, you can decrease the size of whatever 3 phase converter you need to get.

Cheers, Wayne
 
agree with wwhitney.... much of the three phase heating equipment I have encountered can be reconfigured for single phase,
 
To add, the oven is on a timer and only heats up for a few seconds to dry paint. I don't think it has a fan, but would need to make sure.
 
Little Bill said:
A business is taking on some more equipment. The equipment came from a shop that has 3Ǿ power. Their place only has single Ǿ. There is only two pieces of equipment that needs 3Ǿ. One is an air compressor and I plan on an RPC for that. However, there is an oven that operates on 480V 3Ǿ. Currently, in the place where it is, there is a transformer taking 240V to 480V. I'm not sure how to get power for the oven with a RPC. I think their new service will be either 208V, or 240V. So I think the oven would work, but take longer to heat.
Also thought about changing the elements to single Ǿ.

The business doesn't want the expense of having 3Ǿ brought in. So what are your thoughts on powering the oven? Can you use an RPC for a static load like the oven? For the record, the RPC I would get would be for both the air compressor and oven. They would only use one of them at a time.
Click to expand...
Have you checked with the oven manufacture? They might have more info on converting the oven.
 
I recently converted a old commercial oven from 480 to 240, the manufacturer provided a kit with elements a terminal block and a new nameplate took a while to get but was reasonably priced, i was surprised they could get it.
Interestingly they said the oven can run on either single or three phase does not matter just different connections but the voltage of the elements key.
The new elements were marked '230V' and the nameplate '240V' but who's counting?.
 
Little Bill said:
To add, the oven is on a timer and only heats up for a few seconds to dry paint. I don't think it has a fan, but would need to make sure.
Click to expand...
I bet it does, if it drys paint. It’s not a powder coat oven? Those usually heat longer to melt the powder. Being 480 three phase, it’s probably quite a few kw. Don’t you just love it when a customer gives you the bare minimum info!
 
wwhitney said:
Do you have a schematic for the oven, or can you deduce one from opening it up?

Depending on what loads are inside, you may be able to rewire it for single phase without much trouble. For example, the only load on all 3 phases might be 2 or more 2-wire heating elements, connected in a delta fashion. In which case it should be possible to rewire those heating elements to all be supplied by the same phase, so the oven only needs 480V single phase.

Even if it has a true 3 phase load in it like a 3 phase fan motor, the bulk of the load should be the heating elements. So if you can rewire those single phase, you can decrease the size of whatever 3 phase converter you need to get.

Cheers, Wayne
Click to expand...
Can you legally do that? If It has a name plate on it
 
hillbilly1 said:
I bet it does, if it drys paint. It’s not a powder coat oven? Those usually heat longer to melt the powder. Being 480 three phase, it’s probably quite a few kw. Don’t you just love it when a customer gives you the bare minimum info!
Click to expand...
It's not powder coating. It is a quick dry paint for oil filters.
 
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