Mounting mains transformer/general tips.

[antknee]

I need to mount a transformer, it is to be used with a dual power supply board. The board itself seems fine, I'm posting because I'm not sure exactly how to mount the transformer or wire it safely having never done so before.

So I have some questions.

1) The transformer came in a plstic wrap, I should leave it in that wrap shouldn't I?
2) It came with a metal plate, 2 felt plates and a nut and bolt. It looks like they expect me to secure the transformer how exactly?
3) The transformer has two inputs and two ouputs. So I essentially just wire the mains lead to the two inputs in parallel?
4) The mains plug will have a fuse, but I'm fairly sure I should have a second fuse. Should this go between the transformer and the board?

Thanks,

Antknee.

 

[Reloadron]

So I have some questions.

1) The transformer came in a plstic wrap, I should leave it in that wrap shouldn't I?
2) It came with a metal plate, 2 felt plates and a nut and bolt. It looks like they expect me to secure the transformer how exactly?
3) The transformer has two inputs and two ouputs. So I essentially just wire the mains lead to the two inputs in parallel?
4) The mains plug will have a fuse, but I'm fairly sure I should have a second fuse. Should this go between the transformer and the board?

1) Yes
2)Metal plate on top with felt below it and final felt on the bottom between transformer and mounting surface.
3) The transformer is likely a dual voltage primary. For 220 / 240 VAC input you would wire the primarys in series and for 110 / 120 VAC they would be wired in parallel.
4) You should fuse the transformer primary where it goes to the mains. Fuse based on about 20% over the maximum rating of the mains side.

That would be my guess.

Ron

 

[antknee]

Very succinct and looks very correct. Duly thanked

Primaries are 115V AC, so parallel wiring. Probably 1amp fuse will be fine, it is a 15VA transformer, will be hard to find less than 1amp.

Antknee.

 

[antknee]

I wired them in parallel and I get 230V across each primary, that's twice what I need.

How do I wire them in series? Put the output of the first primary as the input of the second primary?

Thanks.

 

[Reloadron]

Yes, per my initial post, since your mains in GB are 220/240 you need to wire the primaries in series. Not parallel but series. You tie two primary wires together and power to the remaining two.

Ron

 

[antknee]

Just did it. Yay It was making a really big humming noise at 230V on both primaries. No harm done though.

Now 120V in both primaries and 22V both secondaries.

Thanks.