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Need help/info on high voltage project

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Clint

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Good evening everyone. New to the forums. So lets start this off I am looking for info on a HV project, I am looking to build a violet wand. I have this image in my head of the project and I'm looking to see if it makes sence. Or is it just making sence in my head lol. Here goes I want to take a motorcycle ignition coil as a HV power supply. The coil is going to put out about 20-30kv I'm going to use a light dimmer of 600watt and a CAP of the right specs to fire this said coil. Next the coil will be attached to a primary coil of 10 turns of at least 16-18 guage wire. I will make a secondary coil of 22-26 or smaller gauge with around 900-1000 turns to jump the ignition coils voltage from 20-30kv to hopefully over 50kv in essence I'm building a small Tesla coil with out a spark gap if I'm correct. The issues I'm thinking I might have are, I'm not sure how to adjust the volts coming off the secondary HV coil. I was thinking that the light dimmer if adjusted lower will limit the voltage coming out of the ignition coil, while limiting that voltage it should limit the voltage going to the primary if the built coil and in turn making the secondary coil lower voltage.... If i am not correct can anyone help with my thinking lol. Also I will be hooking secondary HV coil to a adapter so that I can hook up different tools for the violet wand. I know one endnof that coil gets hooked to this adapted but inam not sure where the other lower end of this coil will be hooked up to. And I want to be safe from mains 120v so also if anyone can tell me or show me how to keep the secondary HV coil safe from mains. I only want the HV low current voltage to touch the skin. Sorry for the rambling and if anyone needs clarity on what I am doing please just ask ;) and thanks for any and all help.
 

audioguru

Well-Known Member
Most Helpful Member
The ignition coil will be zapped and destroyed by 120VAC from a light dimmer. The light dimmer will also be destroyed.
The 10 turns winding of your do-it-yourself transformer will be a dead short circuit to the high voltage from the ignition coil.
 

Clint

New Member
The ignition coil will be zapped and destroyed by 120VAC from a light dimmer. The light dimmer will also be destroyed.
The 10 turns winding of your do-it-yourself transformer will be a dead short circuit to the high voltage from the ignition coil.

Not to say you are wrong but there are MANY projects thatbuse this simple light dimmer coil driver so i dont understand how it Will fry the coil here is a link for a simple dimmer coil driver http://www.rmcybernetics.com/projects/DIY_Devices/homemade_ignition_coil_driver.htm also care to elaborate on why the 10 turn primary will be fried from what I understand a primary on a Tesla coil is around the same amount of windings and is being powered by say a neon transformer of say 15kv. Care to explain how you came to all of these answers ;) thank you and again I'm not saying you are wrong I'm looking for answers notnjust relies ;)
 

MikeMl

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Most Helpful Member
The circuit in the link applies a maximum of 12Vdc (pulsed) to the primary of the ignition coil. You propose connecting ~120Vrms or 170Vpeak pulses to the primary of the ignition coil...
 

Clint

New Member
The circuit in the link applies a maximum of 12Vdc (pulsed) to the primary of the ignition coil. You propose connecting ~120Vrms or 170Vpeak pulses to the primary of the ignition coil...

My bad that was a bad example of whatbi was showing.here is another one
http://www.instructables.com/id/High-voltage-car-ignition-coil-project/

If that link does not work please just Google fan dimmer coil driver there are many sites that show this circuit. From what I'm understanding the dimmer along with the cap create the off and on that the coil needs in order to fire.
 
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spec

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Just some points about automobile/motorcycle coil ignition systems and voltages.

I is quite true that with a traditional Kettering ignition system, either with mechanical points or semiconductor switch, that the voltage applied to the primary of the coil is 12V (or 6V) during the dwell period when the points are closed. At low engine RPM this voltage causes the current through the coil primary to ramp up until the current is limited by the resistance of the coil primary winding and possibly an external ballast resistor. The maximum primary current is normally in the region of 3A to 6A.

When the points open, the primary of the coil jumps up to typically 400V which is transformed to 15KV to 30KV (depending on the particular coil), on the secondary. The typical turns ratio of a coil is not as high as you might expect at only around 40 to 1.

With a capacitor discharge ignition (CDI) a 1uF to 4uF capacitor is charged up to between 100V and 400V by an inverter. At the ignition point the charged capacitor is connected to the primary of the coil which then increases the voltage by around 40 on the secondary.

The thing is that, it is the spark plug that ultimately limits the secondary voltage by arcing over.

About making a transformer to double the output voltage from the secondary of a standard coil, my feeling is that the efficiency would be low and building a 50KV transformer would be quite difficult.

Off the top of my head, I would have thought that you would get much better results by choosing a high performance coil and over-driving the primary to generate the 50KV that you want. Of course, you will be over-volting the coil but you would probably get away with it. I do vaguely remember reading that some ignition coils do in fact produce secondary voltages around the 50KV mark. I would be inclined to go for an automobile coil rather than a motorcycle coil, as an automobile coil tends to be more sturdy.

In any event, you would need to make sure that the coil did not overheat.

By the way, remember that most automobile ignition leads are restive for electrical noise suppression and you may get a fatter spark by using high tension leads without built-in resistors.

In terms of driving the coil, you would get much better results and give the coil an easier life by driving the primary from a custom circuit rather than a mains dimmer.

I made a fantastic spark generator, running at around 10KHz, from a TV line output transformer (LOPT). It was an evil hissing thing, because of the high frequency, and it was great fun, until the LOPT burned out.:arghh:

spec
 
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audioguru

Well-Known Member
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The 4.5uF capacitor between the 12V winding of the ignition coil and the 120v/60Hz AC dimmer has a reactance of 593 ohms that limits the current and voltage. The 60Hz is a slow moving sinewave instead of the abrupt disconnect of distributor points so the coil voltage is reduced.
 
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