Voltage issues at transformer

[Chris1147]

I have a 480v to 240v transformer, I am reading 240volts across both legs but only 63volts to ground, Is this a grounding/bonding issue? Thank you

 

[iwire]

I have a 480v to 240v transformer, I am reading 240volts across both legs but only 63volts to ground, Is this a grounding/bonding issue? Thank you

Are you getting that 63 volt reading on all three phases to ground?

Do you know if this is a supposed to be a corner grounded delta or a ungrounded delta supply?

 

[Chris1147]

This particular transformer is not 3 phase, it requires 2 legs in at 480 and produces 2 legs out at 240..

 

[Chris1147]

It is just single phase. And I am not 100% sure on the grounding type. Sorry for the incomplete info, troubleshooting on the fly..

 

[Chris1147]

Are you getting that 63 volt reading on all three phases to ground?

Do you know if this is a supposed to be a corner grounded delta or a ungrounded delta supply?

This is a single phase transformer, not sure on the grounding type.

 

[iwire]

This is a single phase transformer, not sure on the grounding type.

Ok is the 63 volt reading from both legs to ground?

 

[roger]

If the secondary of the transformer is not grounded anywhere you will get odd readings trying to read to ground or to an enclosure.

Roger

 

[Chris1147]

Ok is the 63 volt reading from both legs to ground?

That is correct both 240 legs individually tested to ground is 63 volts

 

[Strathead]

If the secondary of the transformer is not grounded anywhere you will get odd readings trying to read to ground or to an enclosure.

Roger

I am with Roger, I don't think the secondary is grounded.

 

[Chris1147]

I am with Roger, I don't think the secondary is grounded.

Thank you both very much, I appreciate your assistance.

 

[chris kennedy]

Is there an XO bus on this tranny?

 

[infinity]

I agree no bond present. For a 240 volt secondary it should have 240 volts across X1 and X4 and X2 and X3 should be connected together. The X2/X3 should be bonded to create a grounded conductor.

 

[chris kennedy]

X2 and X3 should be connected together. The X2/X3 should be bonded to create a grounded conductor.

Yup, I'm another guy that never see's 1Ø trannys.

 

[infinity]

Yup, I'm another guy that never see's 1Ø trannys.

We don't do them very often either but I just did one a 50 kva month or so ago.