I see about 21.

???
Skeer's answer was "I don't think I understand.. those VAC values were from a 21.45vac on each of the mentioned primary pairs." which is why we were getting such odd results that didn't make any sense.

 

This thread shows a very good reason to investigate the connections in a device before removing the transformer. At that point it would have been fairly simple to identify the 120 volt connections as well as those used for the inverter active devices and their common V+ connection.

The chart of voltages is rather confusing to me. Were all of those voltages taken with the AC connected to the same two terminals?? Evidently NOT.
Transformer voltage reading are only useful if the excitation voltage is supplied to one set of terminals for all of the readings. Otherwise it is like working a RUBIX CUBE in the dark.

 

This thread shows a very good reason to investigate the connections in a device before removing the transformer. At that point it would have been fairly simple to identify the 120 volt connections as well as those used for the inverter active devices and their common V+ connection.

Yes, I agree. That would have made the task much simpler.

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The chart of voltages is rather confusing to me. Were all of those voltages taken with the AC connected to the same two terminals?? Evidently NOT.
[/QUOTE]

That is why I asked the TS which wires he was connecting to the source -See post #26.

[/QUOTE]
Transformer voltage reading are only useful if the excitation voltage is supplied to one set of terminals for all of the readings. Otherwise it is like working a RUBIX CUBE in the dark.
[/QUOTE]

That was partly our fault. We assumed that he would connect the source to the secondary, based on our years of accumulated knowledge. We ignored the fact that he is a beginner.

 

This thread shows a very good reason to investigate the connections in a device before removing the transformer. At that point it would have been fairly simple to identify the 120 volt connections as well as those used for the inverter active devices and their common V+ connection.

The chart of voltages is rather confusing to me. Were all of those voltages taken with the AC connected to the same two terminals?? Evidently NOT.
Transformer voltage reading are only useful if the excitation voltage is supplied to one set of terminals for all of the readings. Otherwise it is like working a RUBIX CUBE in the dark.

Fair.. in this case however the unit had been scrapped like 3 years ago. And your plug on voltage readings is pretty much what I did. Perhaps I didn't explain or represent it well enough but I applied voltage to each pair then measured any output. Do you think I applied voltage to all terminals at once?

 

We assumed that he would connect the source to the secondary because that's what we would do based on our many years of experience.

Yeah, that's what I did. Except I also connected it to each pair of primaries too, maybe that was ultimately unnecessary?

 

Yeah, that's what I did. Except I also connected it to each pair of primaries too, maybe that was ultimately unnecessary?

It was unnecessary. Do you understand why we only got useful information when you connected the source to the secondary and measured the voltages between the taps on the primary?

 

It was unnecessary. Do you understand why we only got useful information when you connected the source to the secondary and measured the voltages between the taps on the primary?

Honestly? Not entirely, no. From my undersanding the number of turns can be determined from Scratch that.. I think so. If this was a single pri/single sec transformer then you can determine turns either direction right? If it was a single pri/multi sec then you'd use primary voltage and read secondaries. But it's the opposite when it's multi pri/single sec.. right?

 

Honestly? Not entirely, no. From my undersanding the number of turns can be determined from Scratch that.. I think so. If this was a single pri/single sec transformer then you can determine turns either direction right? If it was a single pri/multi sec then you'd use primary voltage and read secondaries. But it's the opposite when it's multi pri/single sec.. right?

You got it right.

 

Honestly? Not entirely, no. From my undersanding the number of turns can be determined from Scratch that.. I think so. If this was a single pri/single sec transformer then you can determine turns either direction right? If it was a single pri/multi sec then you'd use primary voltage and read secondaries. But it's the opposite when it's multi pri/single sec.. right?

You can use the primary if you know the assigned voltages at its taps. Many transformers list the primary and secondary voltages on the nameplate.

 

You can use the primary if you know the assigned voltages at its taps. Many transformers list the primary and secondary voltages on the nameplate.

You will probably NEVER come across any labeling other than a model number on a transformer in a commercially sold UPS device. And those transformers are really application specific because they are both power input for battery charging and power output, for when they are doing the inverter output function. And to do it at an absolute minimum cost means that amazing double-duty winding arrangement.