Author Topic: Ignition Circuit help  (Read 9426 times)

Offline Admiral_dk

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Re: Ignition Circuit help
« Reply #15 on: February 15, 2013, 05:11:16 PM »
OK - it should do the trick with the right resistor values vs. voltage.

Don't touch the transistor house when the engine is running  :zap:

Offline Admiral_dk

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Re: Ignition Circuit help
« Reply #16 on: February 15, 2013, 07:22:59 PM »
Steve

I attached a .pdf with a design for your BU941Z device - hope it helps.

I realized that the value of R1 is too small - or more correctly - it's a good match for a 4.8 volt RC power. I would increase it to 1K5 with 6 volt supply and 4K7 with 12 volt power.
« Last Edit: February 16, 2013, 10:06:49 AM by Admiral_dk »

Offline stevehuckss396

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Re: Ignition Circuit help
« Reply #17 on: February 15, 2013, 11:02:38 PM »
Thanks Admiral!  Do you have another circuit design for the Isolated gate device? The more modern device you talked about earlier.
Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline metalmad

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Re: Ignition Circuit help
« Reply #18 on: February 15, 2013, 11:25:27 PM »
Hi Guys
Would something like this serve for my V8 project?
On a good Day I can just about work out a simple single cyl points ignition system, but its a streach :noidea:
I hope to use a Hall system for the first time on this.
Thanks guys.
Pete
A little bit every day, sometimes the same little bit

Offline stevehuckss396

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Re: Ignition Circuit help
« Reply #19 on: February 15, 2013, 11:44:53 PM »
Hi Guys
Would something like this serve for my V8 project?
On a good Day I can just about work out a simple single cyl points ignition system, but its a streach :noidea:
I hope to use a Hall system for the first time on this.
Thanks guys.
Pete

Yes it would! You could do many things. You could put a disk in the distributor with 8 magnets on it to trigger the sensor (Steve Huck). You could also put a sensor and magnet in the distributor and have a metal disk between them. The metal disk would have "windows" in it so when a window passed by the magnet and sensor "see" each other and operate (George Britnell). You could also put 4 magnets in the flywheel and mount the sensor in the bellhousing and trigger the sensor that way.

The reason I put the sensor in the distributor is it's real easy to adjust the timing. In the bellhousing you will need to figure out a way to move the sensor for timing adjustment.

If you want to just purchase something, S/S has the CDI boards and mini coils with the sensor. I have them in two of my engines and they just plain work.

When you get to that point drop me a PM and post in your thread and we can set you up with about 5 good ways to do it.
Do not be like the cat who wanted a fish but was afraid to get his paws wet.

Offline metalmad

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Re: Ignition Circuit help
« Reply #20 on: February 15, 2013, 11:56:14 PM »
Thanks for the help Steve!
I have a feeling im gunna need it :cheers:
Pete
A little bit every day, sometimes the same little bit

Offline Admiral_dk

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Re: Ignition Circuit help
« Reply #21 on: February 16, 2013, 10:11:44 AM »
As said in an earlier post - I just ordered the parts for a IGBT ignition, so I can do a test "muck up"  ;)

And I will most certainly post the results  8)

I would do it as in a lot of modern cars and as told by Steve above - a fixed magnet and a fixed Hall sensor with a rotating disk or drum with windows in. Remember that the ratio of window size vs land gives the dwell period. In my circuit above - it fires when a window opens and the sensor sees the magnet and the coil is "charged" when they can't see each other.

Best wishes

Per
« Last Edit: February 16, 2013, 10:20:33 AM by Admiral_dk »