Transformer

[Greg Wrenn]

I am in the process of moving drills between two plants. The plant one has a 480 Delta system with a 240 volt bus bar system that the drills started at. I am transferring them to plant two which has a 480 Wye system with the bus bar running 480 volts. I told the manufacturer that I needed transformers that would step down to a 240 Wye system so that I could have a neutral. They sent me, I believe, a 240 delta because their is no "xo" to hook up a neutral. So I am assuming their is no way to hook up a 120 receptacle to this because their is no neutral. First, is this accurate? and second what transformer to I need to ask for to get this accomplished I have some 240 volt drills that run 120 volt pumps. We are transferring these machines from a plant that had a 240 delta bus bar system to a plant that has a 480 wye bus bar system.

In another thread someone mentioned what do I mean by 240 volt drills running 120 volt pumps. These drills had receptacles tied in to the 240 volt disconnect box at the machine but only tied in to one leg so that their would be 120 volts to run the pumps. Unless I am missing something I can not do this with the transformers that I was sent.

 

[hillbilly1]

Another smaller single phase transformer to run the 120 volt stuff would be the ticket. Also, the transformer they sent may have a center tap on one of the windings. Do you have the wiring diagram on it?

 

[jim dungar]

I told the manufacturer that I needed transformers that would step down to a 240 Wye system so that I could have a neutral.

You gave them the wrong information and they gave you the wrong transformer. Two wrongs,no right.

A 240V wye transformer would give you 136V L-G which would not be good for your 120V equipment.

A 240V delta transformer with a center tap at 120V is what you need. Or, a 240V delta power transformer + a smaller 120V control power transformer.

 

[Greg Wrenn]

You gave them the wrong information and they gave you the wrong transformer. Two wrongs,no right.

A 240V wye transformer would give you 136V L-G which would not be good for your 120V equipment.

A 240V delta transformer with a center tap at 120V is what you need. Or, a 240V delta power transformer + a smaller 120V control power transformer.

To be more specific I told them I needed a step-down transformer from a 480 Wye to a 240 Wye transformer. Because I needed a neutral on the low side. I admit I do not know if you would call it 240 wye like that but I was specific that I need a neutral on the low side because I would need to run some 120 volt items on the low side with some of the machines.

 

[infinity]

To be more specific I told them I needed a step-down transformer from a 480 Wye to a 240 Wye transformer. Because I needed a neutral on the low side. I admit I do not know if you would call it 240 wye like that but I was specific that I need a neutral on the low side because I would need to run some 120 volt items on the low side with some of the machines.

A 4 wire WYE transformer would output 240/139 volts. Not sure what 120 volt machines that you can safely operate on 139 volts.

 

[Hv&Lv]

May be way off base, but maybe this is what you needed..

https://www.grainger.com/product/SQUARE-D-3kVA-Three-Phase-Transformer-22LR52

 

[Greg Wrenn]

May be way off base, but maybe this is what you needed..

https://www.grainger.com/product/SQUARE-D-3kVA-Three-Phase-Transformer-22LR52

This looks like it would be right because it talks about the 120 volts on the low side. I would just need a larger KVA but yes I believe this is what I was asking for. I thought I had asked for something like this originally but then the purchasing department tried to go with something cheaper with a different company and it ended up not have the neutral I needed.

 

[kwired]

To be more specific I told them I needed a step-down transformer from a 480 Wye to a 240 Wye transformer. Because I needed a neutral on the low side. I admit I do not know if you would call it 240 wye like that but I was specific that I need a neutral on the low side because I would need to run some 120 volt items on the low side with some of the machines.

All wye systems have 1.732 times line to neutral for line to line volts. If you must have 120 volt loads then three 120 volt coils in a wye configuration produce 208 volts line to line.

If you must also have 240 then a delta secondary with midpoint of one phase grounded (produces a high leg on opposite side) is possibly the best option, just make sure you don't connect any 120 volt loads to the high leg.