audio-talk

I have a Canterbury Windings' toroidal transformer which has two 0-15VAC secondary windings.



Black-White is one secondary and Red=Yellow the other.

I need a 30VAC supply so plan to connect the two secondary wingings in series, th problem is that the transformer isn't labelled so I don't know which is the 'start' and 'end' of each secondary - My starting assumption is that there is a sequence so for 30VAC I would the black and yellow wires and join the White and Red for series use however, that is just an assumption and if I make those connctions and measure it I'll either get 30VAC or something like 0VAC and a lot of heat. I'm seeking advice on resolving this conundrum without doing any damage.

Ta

Start by connecting them in series - you'll either get approximately 0V or 30VAC as you say.

No damage will be caused; you won't get heat.

If you get 0V, they are in anti-phase, i.e. the joint is the same end of each winding; if you get 30V then they are in phase and the joint is opposite ends of each winding....

My guess is that black and orange are the same phase, so join white and orange and measure across black and yellow.

Thanks Gents, I'll try it later.

Looks like red is the new orange for me!

Yep, that was right, cconnected red and white and I measure 33VAC across the yellow and black, obviously with no load so circa 10% regulation it would seem.

Its a 300VA toroid so 30VAC @ 10amps will do nicely for a stereo class A SIT amplifier with circa 2A standing current.

Or just check phase with two channel scope. Mines set up on my desk 24/7 365.

Either you’re photograph is vastly different in colour tone to what you see, or you Ray are colour blind!