Hi guys,

Thanks for the input. The schematic was simply an example. I will be using TIP120 or 3055 transistors. The reason I was going to use an external pulse generator was that I wanted control over the timing. It was said by SM that the coils could overheat quickly if not DE-TUNED. Apparently once the optimum frequency is reached the collector could be overloaded. I was simply trying to avoid that by having external controls.

Protection diodes etc were left out because I was trying to quickly draw up a simple circuit.

.

Just food for thought, that's all

Looking good Rosphere, time to power her up eh??

.

Quote from: UncleFester on March 30, 2007, 01:46:04 PM
Hi guys,

Thanks for the input. The schematic was simply an example. I will be using TIP120 or 3055 transistors. The reason I was going to use an external pulse generator was that I wanted control over the timing. It was said by SM that the coils could overheat quickly if not DE-TUNED. Apparently once the optimum frequency is reached the collector could be overloaded. I was simply trying to avoid that by having external controls.

Protection diodes etc were left out because I was trying to quickly draw up a simple circuit.

With the 555 addition you could put a feedback coil / tranny on coil L4 and trigger the 555. The duty cycle will control the runaway. The ratio will be interesting to see. You could also add a small buck/boost and crowbar that output with an SCR into the power supply. That way the 9vbat is excluded after ramp up. SCR stays on till power dropped. Add a thermal circuit to the 555 trigger acceptance and you'll shut down on overheat.
Good for a start, eh? I have most of this circuit up in my controller so this weekend I can test. No crowbar or thermal, though. But easy to add.
So, what if the TPU bucking is the ramp on and off cycling due to runaway control?

@IS,
I am interested if you posted specs of your coil that gets those voltages. I am truely interested. I get great kicks but no useable power as of yet.
Thanks.

On another note:
I have to replace the heater core in my truck. You know, just under the dash on the passenger side? Used to be you just layed down, undid a few screws, remove the case lid, replace the core, put it all back together and your done.
Not Any MORE! Now you have to lift the dashboard!
We gotta put these bastards outta business.
In the new paradygm the TPU gives everything.

--giantkiller. Less noise, more power is a good thing.