Industrial Setting 3PH 480 to 3PH 240/120 XFMR Sizing

[lochreas]

Hi all,

I'm fairly new to industrial settings and want to make sure I'm appropriately sizing a step down transformer. I've dealt with plenty of 208/120 3 phase, but it's the 240/120 that's throwing me off. This is going to be a portable/temporary setup running off of a 480 210kW generator at a small concrete processing facility. The generator is currently only utilizing 63kW and I need to get 240V to run a 17A FLA well pump, a 115V 15A compressor, and maybe 4 other 15A convenience outlets for a small 8A window unit AC and lighting and laptops. So I'm thinking a small 100A panel setup.

As an example, am I understanding this correctly that the 120V side of this xfmr is only rated for a max of 7A? Is there a better way to do this, maybe with a 480-208/120Y setup and then use a buck/boost to get the 1 240V outlet I need?

3-Phase 480V Delta - 240V Delta / 120

Step-down transformer to convert 3-phase 480V to 3-phase 240V. This unit can be used for reverse feeding. Great for CNC machines, fabrication tools, and more.

store.maddoxtransformer.com

 

[winnie]

Do you need 240V three phase for the well pump, or is it 240V single phase?

You have 3 phase power coming in, and generally you want to balance your 3 phase loading. But delta:delta transformers are a bad choice for running lots of 120V loads, and really only make sense if you have mostly 3 phase 240V loads with a few incidental 120V loads.

A good choice is probably a single phase 480V to 120/240V transformer, sized for your loads.

-Jonathan

 

[lochreas]

Do you need 240V three phase for the well pump, or is it 240V single phase?

You have 3 phase power coming in, and generally you want to balance your 3 phase loading. But delta:delta transformers are a bad choice for running lots of 120V loads, and really only make sense if you have mostly 3 phase 240V loads with a few incidental 120V loads.

A good choice is probably a single phase 480V to 120/240V transformer, sized for your loads.

-Jonathan

I appreciate it. Yes, the well pump is only single phase 240. I just wanted to make sure the loads were balanced and I'm not putting unnecessary strain on the generator long term by using a single phase transformer.

 

[augie47]

With a heavy 120v load you might look at the possibility of operating the 240v loads at 208v and use a 208Y120 transformer. In general 240/120 3 phase transformers have a very restrictive limit on 120v loads.

 

[Ziyad Alahrbi]

Hi,
I don't think this the right transformer to use. The configuration of this transformer is delta/delta connection. They have added a tap to provide 120V with 5% only of KVA of transformer (they are calling it the lighting tap).
I suggest using configuration of delta/delta-center tapped transformer or delta/Y transformer, based on the required voltage as load rating.
Then you have to build panel schedule with breakers location. Determine the loading in each phase and consider future expansion. side your transformer based on the maximum current you have got from previous calculation.

Always comply with your company/country standards and codes.
You might contact suppliers within your country to have technical proposal for your requirment.


Regards.
Ziyad Alharbi