How to get 120/240V Single Phase

[goodoboy]

Hello,

I am learning as I go.

I need to provide power to a 120/240V single phase 4 wire circuit panel with some 120V and 240V loads. I only need to power one 240V single phase loads, the rest is 120V loads.

The problem I am having or don't have enough experience is: my plant only has 120V and 480V 3 phase power. I work in chemical plant. From my knowledge, I can only bring 120V or 480V to the panel.

How can I get 120V/240V single phase power to panel? Maybe bring 480V and then buy a transformer?

Thank you kindly.

 

[templdl]

Hello,

I am learning as I go.

I need to provide power to a 120/230V single phase 4 wire circuit panel with some 120V and 230V loads. I only need to power one 230V single phase loads, the rest is 120V loads.

The problem I am having or don't have enough experience is: my plant only has 120V and 480V 3 phase power. I work in chemical plant. From my knowledge, I can only bring 120V or 480V to the panel.

How can I get 120V/230V single phase power to panel? Maybe bring 480V and then buy a transformer?

Thank you kindly.

Let's revisit the 230v. Would 240v be acceptable?

 

[goodoboy]

Let's revisit the 230v. Would 240v be acceptable?

Thank you templdl for replying.

I meant to type 240V. I left the schematic at work. I have to power a 60A 240V/120V 4 (2 hot, ground, neutral) panel for about 12 120V loads and only 1 240V load.

Thank you

 

[Sierrasparky]

I personally have never seen a plant that has 480v and 120v but no 120/240v.
That being said providing you have the available capacity you could install a tranny from the 480v and get your 120/240.
or if the utility is providing the 120v ask them to install 120/240 and change the panel to match.

 

[GoldDigger]

One thing is unavoidable: your entire 120/240 load set fed by that panel will be fed by one phase (line to line) of the three phase service. (Unless you use a little known multiple transformer configuration to spread that load over all three phases.)

 

[goodoboy]

One thing is unavoidable: your entire 120/240 load set fed by that panel will be fed by one phase (line to line) of the three phase service. (Unless you use a little known multiple transformer configuration to spread that load over all three phases.)

Yes, the loads are 120 and 240 single phase.

Is there anyway to get 120/240 from the 480V at the mcc?

Thanks,

 

[Smart $]

Yes, the loads are 120 and 240 single phase.

Is there anyway to get 120/240 from the 480V at the mcc?

Thanks,

With a transformer, yes. But the real question for us participants is the why and how it is that you have 120V and no
240V. In most (but not all) cases, they go hand in hand (either that or you have 120/208).

... I left the schematic at work. ...

Need that schematic.

 

[templdl]

Yes, the loads are 120 and 240 single phase.

Is there anyway to get 120/240 from the 480V at the mcc?

Thanks,

Not a problem as you simply require aa 1phtranformer with a 480v primary and a 120/240v 1ph3w secondary. How many KVA did you say that is required? What type of MCC do you have?
When providing a transformer pri and sec OCPD are required.
Depending upon the size on the xfmr some MCCs can accommodate an inthral ly mtd xfmr but you may have to add a bucket with a OCPD in order to provide power to an externally mounted transformer.

 

[ActionDave]

I personally have never seen a plant that has 480v and 120v but no 120/240v.....

..... But the real question for us participants is the why and how it is that you have 120V and no
240V. In most (but not all) cases, they go hand in hand (either that or you have 120/208).

Yup.

 

[kwired]

My guess is you have 480 volts supply, and nearly all your loads are 480 volts.

What 120 volts you do have is limited to some general purpose receptacles and/or some controls. This 120 volts is likely derived from a transformer supplied by the 480 volt system, or even from multiple transformers to provide 120 volts at/near each point of use. Each of those may be fairly limited in capacity though.

If you have one central panel so to speak for most/all these 120 volt circuits and it is indeed supplied by a 120 volts only transformer you possibly could re-configure that transformer to output 120/240 (multiwire source) or depending on what load you are adding you may need a bigger transformer anyway. Or just install a new transformer with 120/240 output sized to what you need and leave existing as is.

 

[templdl]

My guess is you have 480 volts supply, and nearly all your loads are 480 volts.

What 120 volts you do have is limited to some general purpose receptacles and/or some controls. This 120 volts is likely derived from a transformer supplied by the 480 volt system, or even from multiple transformers to provide 120 volts at/near each point of use. Each of those may be fairly limited in capacity though.

If you have one central panel so to speak for most/all these 120 volt circuits and it is indeed supplied by a 120 volts only transformer you possibly could re-configure that transformer to output 120/240 (multiwire source) or depending on what load you are adding you may need a bigger transformer anyway. Or just install a new transformer with 120/240 output sized to what you need and leave existing as is.

Yes, yet another "guess." It certainly would be nice if the OP would at least provide some input in regard to what load that needs to be supplied. We keep on shooting at shadows piling up post after post with the lucky chance that the OP wouid get an answer. Per my previous post what would it take to provide the supply voltage which appears too be 480 and that a 120/240 1ph3w needs to be supplied and what the amps or kw of the load is. Otherwise than where the xfmr can be mounted depending upon the KVA (which we don't have a clue is) and the size is f an pri OCPD (depending upon the KVA of the transformer) and where it can be located, and where to locate the sec OCPD.
Frustrating to say the least.
Or am I missing something.

 

[Haji]

In old days ,120V service was available and then replaced by 120/240V service. Is such a practice still continued in the OP's case?

 

[kwired]

In old days ,120V service was available and then replaced by 120/240V service. Is such a practice still continued in the OP's case?

OP is in a plant that currently does have 480 volts. Though not impossible to still have a very old existing 120 volt only service - it is nearly non existent here in the US outside of a few dwelling services.

OP really needs to provide us with a little more information - but my money is still on him having 480 x 120 transformer somewhere in the plant, or even one that has or can have 120/240 secondary.

 

[goodoboy]

Yes, yet another "guess." It certainly would be nice if the OP would at least provide some input in regard to what load that needs to be supplied. We keep on shooting at shadows piling up post after post with the lucky chance that the OP wouid get an answer. Per my previous post what would it take to provide the supply voltage which appears too be 480 and that a 120/240 1ph3w needs to be supplied and what the amps or kw of the load is. Otherwise than where the xfmr can be mounted depending upon the KVA (which we don't have a clue is) and the size is f an pri OCPD (depending upon the KVA of the transformer) and where it can be located, and where to locate the sec OCPD.
Frustrating to say the least.
Or am I missing something.

templdl, thank you for replying and other as well. I apologize for the late response.

Here is the details of the power in the plant.

208Y/120V 3 phase 4 Wire panels

480V 3 Phase 3W panels



Load:
My load is a 60A 120/240V Single phase , 4 wire panel. I have about 9 120V circuits that need power. And I have 230V circuit A/C unit that need power.

Thank you for the help.

 

[ActionDave]

templdl, thank you for replying and other as well. I apologize for the late response.

Here is the details of the power in the plant.

208Y/120V 3 phase 4 Wire panels

480V 3 Phase 3W panels



Load:
My load is a 60A 120/240V Single phase , 4 wire panel. I have about 9 120V circuits that need power. And I have 230V circuit A/C unit that need power.

Thank you for the help.

Are you sure you need 240V for the a/c? Most will run on 208V.

 

[goodoboy]

OP is in a plant that currently does have 480 volts. Though not impossible to still have a very old existing 120 volt only service - it is nearly non existent here in the US outside of a few dwelling services.

OP really needs to provide us with a little more information - but my money is still on him having 480 x 120 transformer somewhere in the plant, or even one that has or can have 120/240 secondary.

Thank you kwired.

We do have alot of 208Y/120V panels for 120V loads.

Thanks

 

[goodoboy]

Are you sure you need 240V for the a/c? Most will run on 208V.

Thanks ActionDave,

Yes, the specification is 240V, this is why I need the 240V circuit. My plant does have a 480V 3 phase panel if a transformer is required.

I need to call the A/C vendor to check if I can power the unit with 280V.

Thanks

 

[ActionDave]

Thanks ActionDave,

Yes, the specification is 240V, this is why I need the 240V circuit. My plant does have a 480V 3 phase panel if a transformer is required.

I need to call the A/C vendor to check if I can power the unit with 280V.

Thanks

Then your choices are a 480V to 240V single phase transformer or feed your panel from one of your 208V panels and buck/boost for the a/c.

Is this some kind of special a/c unit?

 

[kwired]

Thanks ActionDave,

Yes, the specification is 240V, this is why I need the 240V circuit. My plant does have a 480V 3 phase panel if a transformer is required.

I need to call the A/C vendor to check if I can power the unit with 280V.

Thanks

As mentioned most modern AC units operate at both 208 and 240, but one could install a full kVA isolation transformer if you wanted 240 volts, or a smaller KVA capacity and less costly buck-boost transformer to boost the 208 to 240 for the AC if it actually needs 240 volts.

 

[Sierrasparky]

If the A/C unit is only rated for 240 and this is new and was specified by the A/C contractor then he needs to haul the unit back and get the correct one. The plant should not have to jump through hoops and install special things because the A/C contractor did not do his homework.

That is IMHO