Ignition circuit help

[stevehuckss396]

Keep in mind here that I wasn't driving the coil with electronics. I was simulating the points by making and breaking the hot wire leading to the coil.

 

[Lakc]

A reasonable circuit. But, your coil is wired "upside down." The return side of the HV should NOT be connected to the collector of the transistor...

Ground switching or feed switching, the current differences of 1 ohm to the 400v+ primary kick are negligble. The secondary doesnt find ground through the transistor, its ground is the primary, so thats acceptable.

I like the way you've AC coupled the Hall sensor so the battery doesn't get drianed or the coil burned out if the crankshaft is left in the triggered position.

John

There will still be current flowing through the primary, so the capacitor just provides some extra isolation for the hall to avoid self destruction. It is a neet way to do that.

Steve, let me know what you find out with those resistances. I just found my notes and source code for my cdi, and if I cant debug that in time I can whip up an easy PIC microcontroller circuit to get you moving. I should have plenty of parts on hand, and there is always Electronic Connection or Able Electronics locally. Whats the interior dimensions of your box we have to work with?

 

[stevehuckss396]

. Whats the interior dimensions of your box we have to work with?

I will provide a drawing tomorrow as well. Thanks for the help.

 

[canadianhorsepower]

I don't have pins 1-4, I only have a black and red wire on the primary side.

where is your input signal connected to

 

[stevehuckss396]

where is your input signal connected to

Red wire, black is ground?

 

[canadianhorsepower]

[Red wire, black is ground?/QUOTE]
are you using the circuit shown here at the bigining, or something else????
what are you using for input signal points? hall sensor/ opto coupler?

 

[cfellows]

I may be dead wrong, but I think one problem with these small coils is that they don't have much resistance in the primary winding. Jerry Howell recommended using coils with at least 1 ohm or more primary resistance with his tm6 inition circuit.

I think the low resistance is indicative of not many windings on the primary requiring more current to get a decent spark. Hence, you may need more amps to the primary of the coil.

Chuck

 

[canadianhorsepower]

Cfellows, It's hard to judge this one that's why I asked Steve witch circuit is he using
the digram on this post. The output transistor is a TIP 162 an with a to247 case same thing
that bear is using with his TIM6 (nte 2329) But Steve have a TO-3 case this would be the TIM 7 circuit.
If that's the case no way he can drive that transistor with a hall effect

 

[dsage]

jgedde:

The connection of the coil is correct in my diagram (despite what you think concerning "upside down" - whatever that means).
There are only 3 wires on a (automotove) coil + / - and HV.
Inside the coil the low side of the HV output is hard-wired to the coil negative lead. So it's exactly as drawn. As mentioned by someone else the HV is looking for a return to it's low side not circuit ground.
The circuit drives the coil low side just like a conventional kettering ignition. It's always easier to implement a low side driver than a high side driver.

Having said all of that:

Why not just scrap all this TIM crap and the big coil required and just purchase one of the single spark CDI units from here:

http://www.cncengines.com/ic.html

about halfway down the page in the center. They work really well and the tiny coil is on the board. The whole thing is only about 1-1/2" square. Runs on 4.8v of AA rechargeable batteries as well. You can hide it all and do away with the ugly big box typically used to sit your engine on to hide the coil and battery.

Sage

 

[dsage]

Lakc:

There is a big difference in the current consumption of the original circuit and the one I presented when the circuits are sitting around doing nothing. The original circuit consumes almost 250ma. Mine only consumes 6ma. There is no coil primary current when the circuit is not active.

I digress.

Just order one of the CDI systems and be done with all the TIM stuff.

Sage

 

[canadianhorsepower]

I digress.
Just order one of the CDI systems and be done with all the TIM stuff.

Sage

Thanks for your input but this is why Steve didnt go that route. The supplier told himhis system cant do it
please reed this
cheers

 

[stevehuckss396]

[Red wire, black is ground?/QUOTE]
are you using the circuit shown here at the bigining, or something else????
what are you using for input signal points? hall sensor/ opto coupler?

I bypassed the entire circuit. I was trying just the coil and a battery.

 

[canadianhorsepower]

I bypassed the entire circuit. I was trying just the coil and a battery.

witch circuit are you using or where you using without having your expectation?

 

[stevehuckss396]

OK here is the deal

 

[stevehuckss396]

Lakc:


Just order one of the CDI systems and be done with all the TIM stuff.

Sage

I would need to order 2 of them at 60 bucks each. Then mount them somewhere. I understand what you are saying but i think this way is worth trying. It is going to look so much better if I can get this going.

 

[canadianhorsepower]

ok thats fine for the coil
IT"S A twin coil one input two simultanious output????
so far so good
were is a copy of the diagram you are using??

 

[stevehuckss396]

witch circuit are you using or where you using without having your expectation?

I don't understand what you are asking.

I did not try to use any thing except the coil and a battery.

Negetive coil and battery hooked together

Positive of battery to positive of coil simulating points. Touch, let go, touch, let go.

 

[stevehuckss396]

This is the circuit I built. I did not see the point in trying the circuit if the coil won't spark without it. I used this circuit with a 66 caddy coil and it worked just fine.

 

[canadianhorsepower]

your electronic circuit with that huge transistor mounted on your casing
did you try it with these coils?

 

[stevehuckss396]

your electronic circuit with that huge transistor mounted on your casing
did you try it with these coils?

No, If the coil wont spark with the battery it isn't going to spark with the transistor in series with it. I would like to get the coil figured out before I hook up the electronics. I hooked up the caddy coil to the battery and it sparked fine.