Just one of those "impulse" buys at Delaney's, you know.

What do I have and what can I do with it? Transformer and no, it won't fit there.

Type: YS-500E
Cap: 500VA

Ultimately I need something that can supply around 40 volts and 12 amps DC. Even 36V would work, can I gang some old computer power supplies together? SWAP has them for like $5.

Well, it is only 500va (watts) it isn't super powerful.
It can be used as a step up or step down transformer.
It has a 2:1 ratio in it so depending on if you are on the primary or secondary you will double, or half the voltage.
Do not put more than 100-125v on the coil rated 100-110 (X1 & X2?)
if you put 120v on the H1 & H2 side (200-220v) you will get about 60v

Add in a "Full Wave Diode Rectifier"
http://compare.ebay.com/like/1306887...Types&var=sbar

and you will have wicked pulsing 50 to 60vdc
add in some coils & caps & you can take the ripple out.

The problem with simple transformers is the rely on the magnetic fields collapsing from the AC waves to make it through the other end.
AC in AC out.

At 500w you might be able to get a magnetic rated house hold dimmer & roll the voltage down on the top side.
get it to 40v & you'll have about 10-12amps on tap

If you do get some PC supplies they could be paralleled or series'd (careful)... there are some tricks to doing that stuff...
PC supplies are sensitive to heavy startup loads & will shut down to protect them selves

I've got a rectifier and a large cap. I did not know you could control the input to a Transformer with a dimmer switch. Where would I get a "magnet rated" dimmer?

Thanks Gabe.

I would start at home depot/menards/etc.


40v/12a is 480w, You may push that transformer to it's limit.

What's it for?


It may be easier to pick up a few 19-20v laptop power supplies...

Driving stepper motors, the driver board takes between 24 and 42 volts, 3 amps per motor (4 axis board). They recommend a transformer type of power supply (as opposed to "switching"?)

Maybe I can use the center tap to get 30v instead of 60v or is that not how it works?

I'd like to get as close to 40v as possible as the motors seem much more responsive (used LiPos to get 40v, worked great) than at 24v.

3 lead acid batts would be about 42v, but how to maintain a 10-12 amp maintenance charge on them?

Thanks for the ideas.

This "should" work, but no gaurentees...

http://www.homedepot.com/h_d1/N-5yc1...&storeId=10051

I would have to see all the leads on the x-fmr to know how "tap-able" it is. Usually there are a ton of extra wires, or jumpers.

Transformers are simple things & the Ratio of windings is what you are looking for... 120v to 40v would be a 3:1 ratio. (odd or not comon)
1.7:1, 2:1 & 4:1 are comon types in the industrial world.

This looks boss, in sort of an old-timey way. Would this be a good option for the "transformer" part of the power supply?

http://www.ebay.com/itm/Powerstat-Va...item4d04c0203f

that should work,
You can put the full bridge on the output side... careful on overvolting the cap & full-bridge if they are not rated 140v.
Avoid cranking the knob under full load.