Instructables

I need to replace a Transformer component thats about 15 years old, and it has no ratings on it.?

Here is an image of the transformer, the top of it has the letters PSI, the number 4, and had 6 prongs for soldering.
I only have my multi meter at my disposal at the moment, But any suggestions would be highly appreciated.

Ps. what is this yellow component? It has 224K and 2KV ratings on it, I thought it may be a capacitor but it was not in farids.

Many thanks

Kyle


Picture of I need to replace a Transformer component thats about 15 years old, and it has no ratings on it.?
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samaddon1 year ago
you need to check it with a multimeter and buy a transformer as the same resistance as the previous if you can't get one little low resistance or more is also good!
The yellow component with 224K printed on it is a capacitor.  These numbers "2,2,4" tell you the capacitance in a manner similar to the labeling on resistors.  The first two digits are a decimal number, the last number is a power of 10, and this gives a number of picofarads.  For example, for the cap you've got there, the value is 22 times 10 to the 4th pF
= 22*104*10-12 F = 0.22*102*104*10-12 F = 0.22*10-6 = 0.22 uF

The windings on the transformer are going to be harder to figure out.  This might be a poor time to tell you this, but it would be easier if the transformer windings were still intact; i.e not burned open, or shorted, or whatever you've done to it.  A good transformer you could analyze electrically. You know, you could measure the DC resistance of each winding,  and try to figure out how many turns are on there.  

If you're convinced that it's the transformer that's bad, and you want to do an autopsy on it,  it is kind of tricky to take them apart, because there is some kind of glue holding it all together.  The best way I have found to deal with the glue is by immersing the transformer in boiling water for maybe 10 minutes.
KyleofAsgard (author)  Jack A Lopez3 years ago
Thanks, Im replacing all the components as I cant find which components are crap, So say the transformer wasnt burned up, how would I measure the ratings and how would I mathmatically work out what transformer would be suitable?
Not sure what you mean by replacing all the components. It seems like that would be equivalent to buying a new tazer, and I think someone, erm...  Frollard with his "magic smoke" model,  already suggested that.

There are several tricks for sort of feeling out the windings of a transformer.  All of them involve estimating and guesswork.

The windings are always made out of high-purity copper.  So if you know what size the wire is, in AWG, or its diameter, then you know what its resistance per unit length should be.  Thus if you know wire size AND the total resistance of a winding,  then you know the length of the winding.  Then the total length of a winding, divided by the average length of one turn, will give you an estimate for the number of turns in the winding.

You can also look at the total volume of the space where the windings go, and ponder how many windings of wire of a given diameter could possibly fit into that volume.

If your transformer has two good windings, and if you can feed a small AC voltage to one winding, and measure a AC voltage emerging on the other winding, the ratio of these two voltages should be equal to the turns ratio.

If  you have a tool for measuring inductance, like a LCR meter, the inductance measured on one winding, while the other is open, should be equal to the square of number of turns divided by the reluctance of the core.  How do you figure out the reluctance of the core?  Well, that's tricky. I think the easiest way would be to take that core, and put a known number of turns on it, then measure its inductance.

Also for any transformer with a core, there is a saturation point, a point at which more current does not make more magnetic flux.  I cannot think of a good way to find the saturation level without using an oscilloscope and a signal generator.  Supposedly this is all based on physical properties of the core material and the geometry of the core, but if you don't have the datasheet from the people who made the core, well you know...

All in all, transformers are kinda tricky, and that's the reason why you don't often find a transformer with all its specs printed on the outside, in just one or two numbers, the way you do with resistors and capacitors.

BTW, the good news is that I've actually got one of little tazer toys that looks similar the pictures you posted.  The picture of mine is attached.
http://www.instructables.com/file/FZXQ764GGPEU25Y/
I've had this damn thing forever, and I've always wanted to know what makes it tick.  Anyway, I'll see if I can puzzle out the windings on the two transformers on my tazer toy, and I'll write back with the numbers, or make an instructable out of it, or something.


tazer-insides.jpg
Some pictures of transformer cores I recovered from old CFLs using the boiling water trick:
http://www.instructables.com/answers/Is-there-any-use-for-the-tiny-transformers-in-comp/?comments=all#QUDTJ8MG02LSDAZ
NachoMahma3 years ago
.  The yellow thing looks like a Mylar (polyester film) capacitor to me. 224KuF @ 2KV.
What does "224KuF" mean?
. It appears that I got that wrong. See Jack A Lopez's comment. Sorry about that.
two hundred twenty four thousand micro Farads.
frollard3 years ago
My guess is that's some sort of HV transformer -- the bigger transformer puts out lower filtered voltage and the IC runs an inverter to bump it up to 2kv. (I think that yellow thing is another transformer). The X thing looks like a spark gap for safety...

What did it do before? Was it by any chance out of a neon sign or plasma lamp?
KyleofAsgard (author)  frollard3 years ago
It was actually a tazer that I used for a potato cannon ignition.

Thanks, Any recomendations on how I could find a replacement?
replacement: new tazer. Once you let the smoke out you're finished.
Confirmed by other people's replies. It's a capacitor.

The transformer bumps up the capacitor to a few thou volts, at which point the X shaped cross allows a tiny spark to jump -- when that jumps the huge flow of current causes another transformer (the blue toroid thing) to spit out LOTS of voltage, low current.