How to test a transformer?

[AcousticBruce]

I got this out of a computer power supply.
I know there are numbers at the top and I could look it up. But I would rather learn how to test one of these to find what it is.

On the back of the power supply it had a 120/240 switch. SO maybe thats why there are so many contacts?

Is there a way to hook this up and figure out what it is?

I would like to make a power supply with it. SO hopefully I can use it.

**broken link removed**

 

[Nigel Goodwin]

It looks like a switch-mode transformer, you could remove the other parts that connected to it and make a PC power supply.

It's really of very little use, and not really easy to use.

 

[AcousticBruce]

im thinking Ill buy a transformer.

But is there a way to test one of these?

 

[ronsimpson]

If you had a transformer that has stamped on it “60hz, 110V:16VAC 6 watts” then you could get a new one. You could test it. I would apply 11vac 60hz to the primary and see if there is 1.6 volts on the secondary. Note: it is much safer to test at 1/10 voltage.

What you have is a switching power supply transformer that probably works at 100khz. It is not simple! I can only see ½ of the pins but there must be at least 3 maybe 7 different windings. Because you don’t know the turns ratio, inductance, schematic etc. you cannot test it. Probably it is good.

 

[MrAl]

Hi there,

Yeah it looks like a higher frequency transformer that would most likely be
used in a switchmode step down or step up power supply.

To test this thing you have to do a number of things, for example...

1. Use an ohmmeter to determine which windings are connected and which
are isolated.
2. Going by the short lengths of wire coming out of the coil, judge the approximate
current that winding would be able to stand.
3. Apply ac voltages to each winding in turn, and measure the output on the
other windings, then calculate the turns ratio for each winding.
4. Depending on the turns ratios found, determine if this would be of use to you.
5. Apply a variable frequency ac, variable voltage signal to one of the primaries if
possible, then determine what level the core saturates by measuring the current.

A scope helps too so you can check out the waveshapes.

As you can see there are a number of tests that would have to be performed.
Because there are so many leads it makes it a little harder with this transformer
because you have to apply a signal to every pair of leads and measure every
other pairs output voltage to determine how the transformer is wound.

Once you know more about it you can then apply a square wave and see
how well the outputs work by applying a load or loads to the other windings.
You can also see how hot the thing gets.

Good luck with it.