Voltage Step up question.

[hkyle]

Yup I had the same problem...more wraps. 100 turns on the primary working on the 500 (good god) turns on the seconday...this is going to take me all month....lol

Right now I have 100 turns on the primary 100 turns for each choke (2 of them) and now wrapping the seconday side....fun fun fun

Hi Chuck,

It's good to see that you have the basic components in place, such as the 12v power supply, PWM & the toroid. But I think you need more wire turns, maybe primary 100 turns and secondary 500 turns. While the ratio is the same, the increased no. of turns will allow more energy to be transfered. Also I hope you have some sort of over current protection or current limiter in there, cause when the primary saturates, there will be huge current flowing. If you only have 10 turns, the primary will saturate very fast, and after that the primary will become a pure resistor. After saturation, if your 10 turns ohmic value is 0.1 ohm, then the current would be 12v / 0.1 ohm = 120 A. Well, if you don't have any current protection, most likely the PWM will "Rest In Peace" first. I hope this is not the case.

So try to increase the no. of turns to increase the energy transfer and slow down the saturation. Also to avoid saturation current, please try first with small ON duty cycle. Any sign of excessive current, try to reduce the ON duty cycle. If your PWM doesn't allow duty cycle adjustment, try first with higher frequency, so the ON time is shorter.

[Chuck252]

Thanks for the info guys. I will now start wrapping in earnest I guess.

Can a person 'stack' the wraps by doing multiple layers? If so how?

Example:
First layer from left to right. Then go over the top with another layer from right to left? Or would this cancel the magnetic field? I am thinking it would, but help me out if you know for sure.

or should each layer be aligned the same way?
First layer from left to right, then start over typewriter style and go left to right again?

[popeye68]

You can use a transformer from an old pc-powersupply .
They are made for use with pulsed(switching) power ,also
on higher frequenties.
Use them backwards or rewind depending on design.


I don't think a torroid is necessary for testing.

[keithturtle]

@popeye;
Oh, goodie... I got a half dozen of toasted UPS's on the shelf.  Olnyest problem is figgerin' out which two pairs of wires to latch on to-  big fat red, brown, yeller... skinnyer blue, red, purple, orange, white...  man, there oughta be a schematic out there somewhere, but it ain't on the CD that came with 'em.. I looked!

The sun is high on the log,

Turtle

[popeye68]

Hi Turtle ,

i found the windings this way;
-first take a fat wire as starting point
-find all the wires that make contact with that wire (windings are in series)
>now you have all wires from secondary

There is one fat one that's the ground wire

My transformer was like this;
12.0v @ 8A.
5.0v @ 22A.
3.30v @ 14A.
Ground wire
-5.0v @ 0.3A.
-12.0v @ 0.8A

Measure with a ohm meter to see what are the other outputs

I had 3 wires left over , the primary with center tap.

So i used the transformer backwards , can pulse the
+12v/+5v/+3,3v windings and get  pretty high voltages out.
Be carefull!!!

Popeye