Wiring question

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PanPal
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Wiring question

#1

Post by PanPal » Wed Oct 01, 2008 11:06 pm

I am wiring a pan with a magneto. I have a crude wiring drawing but not the same componenets shown. I am running a cycle electric regulator ( square type with 3 wires) Also using a battery eliminator with 2 connection points. The scematic (drawing) shows a capacitor with one connection and a regulator with 5 connections. does anyone have a better scematic that I could follow? I am electrically challenged without a scematic.
MagnetoLightsNoBattery12V.jpg
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Re: Wiring question

#2

Post by awander » Thu Oct 02, 2008 2:36 am

Take a look at
viewtopic.php?t=26&highlight=wiring

You will have to translate the BAT GEN and F terminals on the standard regulator over to your "3 wires".

Also, hook the capacitor up in place of teh battery on thiese diagrams.

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Re: Wiring question

#3

Post by PanPal » Thu Oct 02, 2008 5:44 pm

These a cool drawings, but I do not have the frame mounted coil and the regulator in these have 2 connections instead of three wires. I have one wire on my regulator to The A terminal on the generator and another to the F terminal. The third wire goes to either to one connection on the battery eliminator, or my ignition switch. Then since I have a second connection on the capacitor (battery eliminator) and this drawing I put up shows a capacitor like one in a stock circuit breaker, where does the wire go. It appears it would be the negative wire, but I can't imagine it would go from the capacitor to ground.

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Re: Wiring question

#4

Post by FlatHeadSix » Thu Oct 02, 2008 7:07 pm

Panpal,
I wouldn't spend any more time trying to translate the Bosch wiring diagram in your first post. Use the stock factory wiring diagram but ignore all the ignition components; coil, circuit breaker, etc., and wire the capacitor (battery eliminator) in there in place of the battery. One side of the capacitor goes directly to chassis ground (usually the metal case which encloses it), and the other side to the "Bat" terminal on the ignition switch. The "bat" on the regulator should be tied to the "bat" on the ignition switch (which is now just a light switch since the mag has a separate kill switch).

mike

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Re: Wiring question

#5

Post by awander » Thu Oct 02, 2008 7:48 pm

the regulator in these have 2 connections instead of three wires
Panpal:

I don't think you looked very closely at the drawings.

The first one shows a cutout relay with 3 terminals(only 2 are used in this diagram), and the 2nd aand 3rd diagrams show a 3-terminal regulator.

The second wire on your capacitor is probably ground-I can't imagine what else it would be for. make sure you hook up the cap in the proper polarity-if you hook it up backwards it will likely explode.

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Re: Wiring question

#6

Post by PanPal » Thu Oct 02, 2008 9:18 pm

I don't think you looked very closely at the drawings.
I think you are right!

Andy and Mike. Thanks. This should be everything I need.

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Re: Wiring question

#7

Post by awander » Fri Oct 03, 2008 12:34 am

Let us know gow it works once you get it done!

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Re: Wiring question

#8

Post by PanPal » Fri Oct 03, 2008 6:55 pm

After thinking about this.........

The magneto says never apply voltage to it.

If I ground my capacitor to the frame, when I push the kill button to the magneto, wouldn't residual voltage backgfeed into the mag. Could this be a slow coil damaging problem?


When the bike is off, will the charge in the capacitor drain with it grounded to the frame? Or does it take shorting the 2 connections together to drain the capacitor? When generating electricity a generator would have resistance or be harder to turn, not much resistance, but the generator would be trying to recharge the capacitor on the initial kick.

The only reason I question these things is the scematic I would be following is from a normal daigram on a bike that runs a battery and a circuit breaker. I have heard of a few people breaking down because the coil in the mag went bad. They used magnetos on airplanes and tracktors that were hand crank starting motors and you would think they would be very reliable if you were using it on plane engines.

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Re: Wiring question

#9

Post by awander » Fri Oct 03, 2008 7:11 pm

The only connection between the magneto and the rest of the electrical system is through the grounded frame of the bike. This is considered to be at "zero" volts.

You would have to connect a voltage to the "other side" of the magneto to damage anything-and that wire goes through the points to ground, also.

So don;t worry about the magneto.


Next, the capacitor will slowly discharge when the bike is off, and by the time you go to start it again, it will probably be completely dead or discharged. To discharge it quickly, you would have to short the 2 cap wires. This will make your generator work on the first few kicks to try and charge the cap, and it may make it harder to kick-kind of like kicking a bike with a dead battery.

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Re: Wiring question

#10

Post by FlatHeadSix » Fri Oct 03, 2008 9:41 pm

PanPal,
Like Andy said, the magneto and charging circuits are completely separate, the only thing they have in common is the chassis ground (frame), there is no positive potential from either of the circuits available to the other one.

Capacitors are all designed differently for specific purposes. Most of them, like the one inside a distributor or timer, or the ones they used to put on charging systems to eliminate radio interference, will charge and discharge VERY rapidly. Most of them also have a low "capacity" which implies that they don't hold much to begin with so it doesn't take a lot to charge them up. The little capacitor inside the timers absorbs almost full sparkplug voltage every time a plug fires, somewhere above 10,000 volts, to keep the points from arcing and welding themselves together. Have you ever had one of those shock you?, or got one to arc when you grounded it?
A capacitor that does not discharge rapidly is called a battery, ever wonder they have the same symbol in electrical schematics? Anyway, bottom line, the capacitor will not hurt the mag or make the bike harder to kick. The magneto itself provides far more resistence to your kicking effort than the generator ever will.

mike

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Re: Wiring question

#11

Post by awander » Sun Jun 14, 2015 6:02 pm

I just noticed, Mike, you wrote, "The little capacitor inside the timers absorbs almost full sparkplug voltage every time a plug fires, somewhere above 10,000 volts, to keep the points from arcing and welding themselves together"

This is not quite true. The high voltage that goes to the spark plugs is on the secondary side of the coil, and never gets to the condensor(capacitor) that is across the points. This capacitor sees only the low-voltage side(primary) of the coil, and though the voltage will spike up above the 6V battery voltage( as the magnetic field collapses) it does not go up anywhere near as high as the voltage on the secondary side of the coil. If it did, there would be no need for the secondary coil winding.....

I haven't measured it, but I would guess it might reach 100-200V for a very brief time, if the capacitor was not connected. The capacitor has the effect of absorbing this voltage spike on the secondary winding, which both protects the points from arcing, and gives a stronger spark on the primary side.

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Re: Wiring question

#12

Post by 58flh » Mon Jun 15, 2015 1:12 pm

Panpal---As the guys were saying As long as the bosch is wired & grounded correctly --you will have no trouble with the eliminater/But I found that using 2 capacitors works better then 1.The 1 will keep your lights-brite for a minit!/Then it seems that the headlight (naturally starts going dim.We put 2 eliminaters One from a vender the other came out of my old RCA B&W TV :D -I olny went to color 5yrs. ago.But I have some cool lectric parts that I read about now & then.Anyway the 2-Eliminaters Held the headlight for a full 3-min.15sec.& it was time to go.Just figured I throw that in before you solder-up & find you need more stored juice.---That capacitor was bigger then the battery eliminater that they sell!It was larger by 50% easily.--Respectfully---Richie

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