Greetings 208V to 480V upgrade question

[bonded&grounded]

Hi all! Upgrading an older building, asking if I can safely run a 480V AHU from a 208V feed using a transformer. Thanks for having me.

 

[Andre Tardif]

Your question is a bit vague, but yes, you can do it.

The type of transformer you get will depend on what loads you will have. You will have to get one with an appropriate power rating.
Do you need a neutral with the system? If so, then I think you will need a transformer that is rated as a 208Y/480Y if I remember correctly.
Anyway, there is a lot that goes into picking the correct one for your needs.

Andy.

 

[General_Valeria]

i'm a bit confused with the question there. but did you get to figure it out?

 

[PGB1]

Hi all! Upgrading an older building, asking if I can safely run a 480V AHU from a 208V feed using a transformer. Thanks for having me.

Hi

I am guessing that by "AHU" you're referring to an Air Handler, such as a make up air.
If so, it might be less expensive in the long run to convert the unit to operate on 120/208 Wye. There may be only one motor to change (or re-tap if it is multi voltage) and some minor rewiring to bypass the internal Step Down transformer(s). You might be surprised and find that the motor has taps for 208 volts.

But if you need 480:
After verifying power is available for the unit, be absolutely sure to buy a Step-Up transformer. Don't do what many people try and put in a Step Down backwards. The transformer will struggle and die soon.

If by AHU you're referring to an air handler, typically it will want the three phases and the equipment ground. Any neutrals required for contactors & such will be created by a Step Down transformer inside the unit. (Step Down for controls are common in AHUs but neutrals are rare.) It will also have another transformer to step down to 24-v for controls.

Paul

 

[Alan]

Hi all! Upgrading an older building, asking if I can safely run a 480V AHU from a 208V feed using a transformer. Thanks for having me.

Circling back since this thread’s been up for a bit. Did you end up using a transformer for the 480V AHU, or was there another approach that made more sense?


An update could help anyone running into a similar upgrade.

 

[TrevorBelmont]

oh big project. how'd the overhaul of the older building go?