Buck transformer current question

[woody]

I have this big resistive load that I would like to power with about 76v AC. But I figure that would be about 12.16 A and I don't have a transformer like that. But I do have a 44v 16A transformer. So if I simply wire that as a buck transformer I can get my line voltage down to about 76v but my question is how many amps would I now be pulling from the ac outlet ?

 

[PRR]

What is your wall voltage?? There's folks from everywhere here.

Assuming Tyrone uses 120V:

76V@12.16A is 924 Watts. 924W@120V is 7.7 Amps. Allow a generous 10% for winding losses, 8.5 Amps.

 

[Mark Tillotson]

The power can only end up in the load (and as losses), so power out = power in - 10% loss.


You can also do the detailed calculation seeing about 4.5A in the primary subtracted from the 12.2A load current...


Get the phasing wrong and you'll see 164V out and > 4kW, so don't get it wrong!