I have been working on getting the voltage up in my cell. I know you can hook batteries together and get it done that way.
I thought that you could also use a transformer on AC or pulsed power to increase voltage. So I wrapped a toroid ( see below) with 24ga wire on both the primary and secondary. The primary has 10 turns, and the secondary has 50 turns.
It doesn't seem to do anything though, and I need some tips on how to get it running, or why it doesn't work etc...
I have the Chapp PWM with a 12v 2.5a input which goes into the toroid as the primary. The secondary doesn't show any voltage at all. I have flipped the polarity and still nothing.
What am I doing wrong?
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.
That would be my approach, cuz there ain't enough field getting up in the primary. No first hand experience with that one yet; jes an observation from what I've read.
Turtle
not enough turns. youll need like 400 on 2ndary just my .02.nd your chapp pwm wont push this much ,Moab
Hi Chuck ,
your transformer will probably only work on high frequency's of >20.000hz
Some info and calculators :
http://www.bcae1.com/trnsfrmr.htm
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
Quote from: kentoot on July 13, 2007, 01:13:54 AM
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.
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?
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.
@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
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
Thanks, POPEYE!
Now to get a 100X probe fer the scope to see those kV spikes!
BTW, can y'all cipher out what resistor to use with regular scope leads?
I don't know much about scopes, but am trying to learn.
Turtle
Hi Turtle,
Yes, you can use resistors to step down the voltage. Actually the resistor value will pretty much depends on your oscilloscope input impedance, but if you want to try things first, you could try with very high ohmic value first (like 1M to 10M ohm). Probe a known voltage source (say, a 12v dc power source) and try to measure with and without the resistor, you will know the effect of the resistor. You can use higher resistance for more step down measurement.
But i'd like to point out another important matter, that's the oscilloscope isolation.
In many Stan's replication cases, I saw people measuring floating (not grounded) high voltage points with a grounded probe, this a big no-no.
If your oscilloscope is not isolated, I think you will need to isolate the probe first with a differential high voltage probe, like these :
http://www.tek.com/site/ps/0,,51-11195-INTRO_EN,00.html
http://www.powertekuk.com/dp9030.htm
Isolation is even more important if you're probing, at the same time, the primary and the secondary side of a transformer. You will also need channel to channel isolation, not just an isolated oscilloscope. That means each channel is totally isolated from each other, the probe ground leads are not connected together to a common ground.
If your oscilloscope don't have channel to channel isolation, you will need to isolate each channel with some sort of an isolated differential voltage probe (see above link).
So personally I would suggest to buy an oscilloscope with channel to channel isolation :
http://www.tiepie.com/uk/products/External_Instruments/USB_Oscilloscope/Handyscope_HS4-DIFF.html
http://www.tek.com/site/ps/0,,3M-10566-INTRO_EN,00.html
and personally I can't afford any of them :).
Thanks, Kentoot;
Both scopes are older tektronix solid state, one is 2 and the other 4 channel- rather elaborate, but I ain't sure about isolation. Two of four channels have ground switches.
I'm about as ignorant as a turtle's carapace when it comes to scopes, and I don't wanna trash either one. I really gotta spend the time to learn their proper use. I downloaded a training pdf from tek that is geared more to the newer stuff, but can glean some basic operating understanding from it.
My head hurts. Back to the basking lamp.
Turtle