Polaris ignition theory

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Jdfiddleman
Posts: 6
Joined: Thu Mar 16, 2017 8:46 am
Real Name: Kurtis
Location: Bethel pa

Polaris ignition theory

Post by Jdfiddleman »

Question for any electrical techy out there. I have a 1980 Polaris Apollo 340 and recently I have been working on the ignition system, I like to know exactly how things work when I'm working on them. So I'm looking for some good explanation of ignition system theory's for this system (stator, points, condenser, coils [primary and secondary]) . I guess what is also a little confusing to me is the AC system, since I am used to working with DC systems. Any explanation of how this stuff works would be much appreciated. Thank you!

P.s. I'm really a John Deere sled fan,I run both a trailfire and a sportfire:)

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JDT
Posts: 5561
Joined: Wed Nov 21, 2007 1:00 am
Real Name: Todd
Location: Milbank South Dakota

Re: Polaris ignition theory

Post by JDT »

I pulled up a wiring diagram for a 80 Apollo and gave it a look-see.

As compared to a JD model like you are familiar with the major difference is the Polaris has points ignition while your Deere's have CDI.
Other minor things would be the brake light switch on the Polaris works on hydraulic fluid and the sled from MN has separate brake and taillight bulbs.

That would be about it. They both use AC power for the lighting, as most all sleds do. There can be some differences in machines that have electric start however.

The external coils on Points Systems work pretty much the same as the CDI machines. The real difference is what is on the stator itself.
However the lighting coil works the same on either regardless of the number of lighting coils used on the stator.

The Apollo uses a "open" ignition system which means there is no connection between the sets of points to make spark. Turn the key or flipping the emergency switch closes a connection between the points and prevents the internal coils from making a current through them.

Theory of operation is that when a set of points open and close a small current passes through the points on it's way to ground. This current then goes through the external coils which acts like a transformer and steps up the voltage to a very high level which induces a spark to jump across the gap on the spark plug electrode.

If the points contact surface is dirty, rusted, or not the correct width the spark may not happen due to lack of a path to ground.

The condenser(capacitor) is necessary to prevent the point gap from burning up from the arc. If the condenser is shorted you will not get any spark as there will never be any current through the coil. If the condenser is open the points will burn up real fast.

The stator plate on the Apollo is essentially two identical ignition systems that only share a common ground. The nice thing about this arrangement is you have something to compare with when trouble shooting. Both coils should read relatively the same as far as resistance (OHMS) goes. Both condensers read neither open or short and close to each other. Either set of points should read zero ohms when closed and infinite when open at the recommended gap.

Same goes for the external components. The primary and secondary windings of the each of the external coils should read the same. Both plug wires the same... preferably zero ohms.

The other things that should be checked is grounds. And ohm meter reading between the stator plate and the engine or the chassis should be zero ohms. Bad grounds anywhere on the sled can effect proper operation of any portion of the electrical systems.

Are you have specific problems or were you just looking for general info?
Todd Schrupp

Milbank SD
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