Transformer Hookup

[quogueelectric]

It should have a ground reference already

It should have a ground reference already

If you want to know if there is an internal ground reference just put a voltmeter from secondary phase to ground and see what it reads. If it is a wye to wye with the secondary being used as a delta the secondary winding will already have a ground reference through the primary neutral.

 

[don_resqcapt19]

quoqueeelectric,

If you want to know if there is an internal ground reference just put a voltmeter from secondary phase to ground and see what it reads.

If you use a high impedance input volt meter (most digital meters are high impedance) you will see voltage as a result of capacitive coupling. In many cases this voltage will be that same as you would expect to see on a grounded system.

f it is a wye to wye with the secondary being used as a delta the secondary winding will already have a ground reference through the primary neutral.

A grounding connection on the primary side does not create a ground reference on the secondary side. There is no electrical connection between the primary and secondary.
Don

 

[quogueelectric]

as stated wye to wye

as stated wye to wye

If the xformer in question is one of the most common wye to wye the center tap of both wye configuration are common inherently so if you ground it you are gounding both. Also there is nothing wrong with using a high impedence meter as long as you know how to use it correctly Wiggins were great 30 yrs ago before the computer was introduced. Now it is a dinosaur which belongs in the tar pits for modern electrical work. Unless you want to carry more than 1 meter which is just silly.

 

[don_resqcapt19]

quoqueelectric,

Also there is nothing wrong with using a high impedence meter as long as you know how to use it correctly

If you use a high impedance input meter on an ungrounded delta system and take your measurements at the line side of the secondary OCPD, with the OCPD open, you will often read exactly the same voltages as on a grounded wye system.

If the xformer in question is one of the most common wye to wye the center tap of both wye configuration are common inherently so if you ground it you are gounding both.

Can you provide an manufacturer's link to such a transformer?...I have never seen one like that.
Don

 

[LarryFine]

Also there is nothing wrong with using a high impedence meter as long as you know how to use it correctly Wiggins were great 30 yrs ago before the computer was introduced. Now it is a dinosaur which belongs in the tar pits for modern electrical work. Unless you want to carry more than 1 meter which is just silly.

If I could carry only one meter, it would be my Knopp K-60. Its readings are often more usable than a volt-meter's for most trouble-shooting.

Detecting the real presence of power is often more important than knowing exact voltage, especially if you might be reading induced voltage.

 

[quogueelectric]

testers

testers

If I could carry only one meter, it would be my Knopp K-60. Its readings are often more usable than a volt-meter's for most trouble-shooting.

Detecting the real presence of power is often more important than knowing exact voltage, especially if you might be reading induced voltage.

Real power is also low voltage signal power it is all real power and all follows ohms law. If you feel you need a load carry a few resistors with you.

 

[quogueelectric]

You are correct

You are correct

quoqueelectric,

Can you provide an manufacturer's link to such a transformer?...I have never seen one like that.
Don

I have been working insane hours and have had a brainfart the most common is a wye delta and usually the service is 480 wye grounded at the service and the 120/208 is a sds. The reverse situation does leave you with an ungrounded hv delta and I guess you could corner ground it yet that is as confusing as an ungrounded wye. I have only seenone of each situation in 30 yrs. Once a corner ground in a lipa power plant 480 v distribution where the gen leg grounded out so the 5000 amp buss read 0 volts to ground yet 480 phase to phase. freaky. And secondly an ungrounded sds on a hospital emergency feed which did not read voltage to ground yet phase to phase was 480.