[ccoleman]

Hi all,
I'm wondering if it would be possible to wire this transformer to run off of 115v and output ~60V? If so, how?



I did try it by putting 115V to H1 and ground/neutral to the secondary- (assuming they share ground) but there was no output, nor did it trip my power strip...

Thanks in advance.
Chris

[wayneb]

According to the transformer label; active and neutral to H1 and H3. For more current link H4 to H1 and H6 to H3.

[Al_The_Man]

As you can see by the label it is 208/230/460 parallel or series for the different voltages.
It cannot be ran on 120 successfully, there is a way to use one 0-208 primary and use the other winding H5 & H6 in buck mode to create a 196v primary but it is going to be in a crippled fashion, VA wise.
Otherwise use the 208 connection shown and you will get half voltage secondary output at derated VA.
Al.

[wayneb]

The transformer is basically a 2:1. if 230 VAC is put in you get 115 vac out. If you put in 115vac in you will get 57.5 vac out.
Don't forget DC rectified will give approx 81 Vdc

[ccoleman]

@wayneb - that's exactly what I was hoping to achieve ~80VDC.

@Al - I don't know how to read that label, but I would've assumed the same thing wayneb said. Can you explain it a bit more?

Thanks,
Chris

[Al_The_Man]

Actually if you follow the instructions for each method of hook up and relate it to the primary diagram it shows the series and parallel arrangements for each type of voltage selection, as I mentioned if you follow the connection for 208, this would be the one you use if you want the best scenario but the 120v input but it will give you 65v output.
Use the parallel 230v input diagram for the lower one, 56v~57.
But as I say the VA will be derated due to the lower efficiency.
Al.

[mike_Kilroy]

so what it means is your 1kva xfmr @ 230v (4.3amps rating) will be good for less current at 120v. I would expect the 4.3amps to reduce to maybe 2 amps because of the reduced magnetic field from running it at 1/2 rated voltage. So this 1kva xfmr will give you the output voltage you want but it will be good for about 2a*120v or 240va now, not 1000va anymore. If that is enough for you then you will be good to go. So your output will be 60v@4-ish amps ac or 80-ish vdc @ 3-ish amps.

If this is sufficient for your need, they go for it; I would keep an eye on the xfmr temperature to make sure it does not overheat. Run it as hard as you will and in abouit 30 minutes it will be at max temperature. It is not possible to say exactly how much derating you will have because different mfgrs design to different mag flux levels by a factor maybe 2 or 3:1 range, depending on the design, need, and how cheap it had to be mfgred.

[ccoleman]

Wow, I never would have guessed it would derate that far, but I guess I'm not surprised either. It certainly would have been marginal anyhow... but sometimes marginal and FREE wins. I guess I'll need to order up a toroid.
Thanks for all of the info guys. Helped a lot.
Chris

[Al_The_Man]

The nice thing about the toroid is you can easily add those auxiliary overwinds on.!
Al.

[mike_Kilroy]

WHY NOT TRY ur free xfmr first? best case it will give you 500va (1/2 the voltage) not likley, but maybe - like I said, unless you know how it was initially designed you dont know for sure..... but free if free - try it - if it wont hack it you will find out by the heat or dropping voltage. THEN buy the torroid, no? I did not mean to discourage the free start!

[wayneb]

I agree, give it a go. You will still have approx 80 dc and 6 Amp to play with (500VA)