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Breakaway Switch


Titan

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What would be the correct way to wire a breakaway switch into an ignition system using a coil and points? The switch has two wires that have continuity when the plunger is pulled out. TIA!
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quote:
Originally posted by firefoxz1
I would say one wire goes to the points and the other to ground.
Yep, most key switches go to ground. Elon
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with the key on and the plunger in, you have an open circuit. With the plunger pulled out, or the key in the off position, you have an closed circuit. Elon
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I do not think it will work with coil and points, however it would work on system where ignition is shorted out.
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If you have a magneto system, the kind of switch you have can be used to short the points to ground just as the ignition switch does. If you are using the battery-coil-points system, then you need a switch that is closed when the plunger is in and opens when the plunger is pulled out. This should be wired between the battery and the ignition switch.
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I wired it up this evening with one wire going to ground and the other wire going to the - side of the coil. It works, but I don't know if it will harm anything.
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DC voltage is pretty strait forward. If there is no load on the wires (which in your case there is not) then all you are doing is interrupting the normal operation. Harm's way would be if you were energizing instead of interrupting. You should be safe.
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"I wired it up this evening with one wire going to ground and the other wire going to the - side of the coil. It works, but I don't know if it will harm anything." Caution!!!!! If you are using a coil instead of a magneto the method described is taking the coil "-" or ground to ground. Yes, the engine stops since the ground through the points has been shorted to ground at the coil. But, this method leaves battery voltage on the coil. Not a problem if you remember to turn the key off. Otherwise the battery can run down and it might harm the coil by having battery voltage on it all the time. My thinking is the breakaway switch should interrupt the voltage from the key (e.g. battery) to the coil. This protects the coil and the battery. Free advice; take it for what it is worth.
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I guess I missed the part where the key was still involved. This would make me question why an interrupt would be needed unless the key switch was faulty. Just my 2 cents worth. If the key switch is NOT doing it's job of shutting the tractor down then you have only to use your plunger switch in PLACE of the key switch to gain equal and safe response to all the operating components. This is assuming your key switch was correctly wired to begin with. Roy, thanks for the added insight to the potential root of the problem.
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Another observation according to Titan's description of his kill switch. If you remove one of the polls (+ or -), there is no risk of wasted detonation, point fusion or coil discharge. Which is how I read it this time. But then again, it's 3:15 in the morning so I may have again misenterprited Titan and his resolution. I'm sure I will be corrected if I have missed something. That's what is so wonderful about this sight. One man's view may not be correct vs. a more observant members abilities to read between the lines.
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Negative/Wrong The safety switches are in the Start circuit not the run circuit. Once the tractor has been started the safety switches are out of the circuit. A breakaway/kill switch circuit is very simple. You either ground the points or cut the power to the coil depending on ignition system. On a magneto points ignition system the breakaway/kill switch pulled on goes to ground. (Normally open switch, pushed in contacts are open, pulled out contacts are closed) On a battery, Coil, Points ignition system the breakaway/kill switch pulled on opens run circuit cutting power to the coil.(Normally closed switch, pushed in contacts are closed, pulled on contacts are open) The key/ignition switch is bypassed so it doesn't matter if it is left on or not. A Kill switch is nothing more than a remote mount ignition switch that can be turned off in an emergency by another person with either a lanyard or radio signal.
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Thom, The group I pulled with required that the inlet air be blocked, causing the engine to instantly flood and die. Starving it for fuel takes too long for the engine to stop running.
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I have used the same "kill" switch (closes on activation) on both Briggs and Kohlers in our pulling tractors. Ground the points on the Briggs or connect to "-" terminal on the coil on the Kohlers. The key is NOT part of the circuit. Rod when our friend pulled the 7790 Diesel we had a cable on the fuel pump lever that pulled a pin that let the lever (with spring help) close. This shut the Lambardini diesel just as fast as a gas engine. The pulling clubs tested it and OK'd it because of how fast it worked.
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Maynard, "The safety switches are in the Start circuit not the run circuit. Once the tractor has been started the safety switches are out of the circuit. " How come my Sovereign stops if I get off the seat when it is in gear and/or the PTO clutch is engaged???? The seat safety switch does kill the engine if it is in gear or the PTO clutch is engaged.
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Granted the seat safety switch on the newer tractors, If it is in gear and/or the PTO clutch is engaged. The older tractors only prevent the tractor from starting if in gear or PTO is engaged. Not all OEM factory safety switches are created equal.
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Mike, We were pulling under ATPA rules at the time I was talking about. This was the rule for all diesels at that time. I don't know if the rules have changes since SVTPA is now associated with Pro Pulling.
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Rod, I know all the big tractors (except farm stock0 require the air shut off. In the diesel garden tractors that pull, the only one that I have seen that did not require the air shut off flap was the 7790 that my fried pulled. It shut down as fast as any gas tractor.
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Mike, Maybe your pulling group allows the fuel cut-off. I was talking about garden tractors also. SVTPA that I pulled with was first a member of NGTPA, then later ATPA, and now Pro Pulling. As far as I know, this is the only garden tractor pulling organization that currently associated with the Pro Pulling organization. I think it was the only garden tractor pulling group that was associated with ATPA also. They have to meet the same safety rules at the big boys. With the turbocharged and intercooled diesels putting out 135+ horsepower, they are very safety conscious, especially with tractors like "The Boomer".

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