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10 ohm resister

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160dan

03-29-2008 19:49:35

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Couple days ago, I was helped out with question RE: why I cant shut off my H with switch...just keeps running though I used the 12v conversion chart...without a light though. I located a piece that I took out of my wiring. It was located about 6 inches from the coil. It could this be the 10 ohm resister I need back in-line to shut the motor off? It's a bout 2 inches long, gray covered male end and one brown covered female end. Middle is plyable black shrink-wrapped rubber. Ring any bells? I don't have a light but if this is not the answer to shutting the motor down, I'll inquire about putting a light in the system. Thanks, Dan

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160dan

03-31-2008 12:06:34

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Re: 10 ohm resister in reply to 160dan, 03-29-2008 19:49:35

JimN...thanks so much! Seems the diode I've got is small or nearly no resistance but it is directional or so I think as the meter showed OL or something like that when turned around. If you're will and can take it, watch for my new posting...I opened up the wiring box today and repainted etc...new can of worms for me.

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james rumph

03-30-2008 10:22:46

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Re: 10 ohm resister in reply to 160dan, 03-29-2008 19:49:35

Food for thought "auto" coils Do Not have a ballest resister built in like tractor coils.

Tractor coils wether 6v or 12v have them internal so a external ballest resister is not needed. If you run a hotter after market coil MSD , Accel etc etc then the external ballest is required. It will run fine but you will find your coil getting very hot.

When i went to 12v neg ground i never needed to install a diode with my generator.

If it has a alt then it should be diode protected internaly that is also why you no longer need the external voltage regulator.

A diode in line is just fixing another problem " voltage fed back".

If it has a old stile regulator then open it up and set the correct gap and the problem is solved.

With the gap to big the points don't close grounding it out allowing voltage to contune threw keeping it running.

With the rpm lower the current isn't as high so they close .

If this has a Alt then this doesn't work in this case.

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Janicholson

03-30-2008 15:20:27

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Re: 10 ohm resister in reply to james rumph, 03-30-2008 10:22:46

Just educational Stuff.
There are three terminals on the Alternator he is using. The large terminal goes (with 10 ga wire) to the load side of the Amp gauge. This wire is supplied with Overlapping DC pulses from the stator windings. There are 6 diodes in the housing of the alternator making 3phase AC into pulse DC. The output voltage is controlled by a internal transistor regulator. This regulator is fed DC reference voltage from the Big post through a 14ga wire going to the #2 labeled spade terminal on the edge of the alt housing. The regulator is initialized from a wire going to the ignition switch (also about 12.5v or so) This wire normally goes first to the idiot light on the dash of a car(or tractor if desired), then to the #1 terminal. The number one terminal appears to be a ground when the key is first turned on. This "Exciting" voltage (engine not started yet) is what causes the idiot light to illuminate. As the engine starts, the exciting voltage allows the regulator to start feeding real current to the rotor windings making the stator produce more voltage than the battery. It charges. The regulator senses the charge voltage and switches the #1 terminal to system voltage. Now the idiot light sees system voltage on both wires, and goes out. This indicates to the driver, that the alternator is charging. This system voltage on the #1 wire through the light bulb is not sufficient to keep the engine running (when the ign sw is shut off, The resistance of the light bulb is too high to allow enough current to make the ignition work. Though it is connected to the same terminal on the ignition as the coil.
The engine stops, and the voltage regulator resets to have #1 terminal act like a ground, ready for the next time someone starts the tractor/car. A diode in the wire (in place of the idiot light bulb) will do the same thing. Preventing back flow from the #1 terminal to the ignition sw, and thus back to the coil. The band end of this (much smaller ~3 amp diode goes toward the alternator so the flow is blocked from that direction.

On the generator topic, The regulator and all circuits associated with generating charging voltage are separate from, and not connected to ignition circuits. Thus there is no way for a regulator to either prevent stopping the engine, or keeping it from starting when operating with the wires in the correct location in every setup I know of (Prestolite, Delco, Bosch, Lucas, and others not mentioned). Again, I have no grudge here, just 50 years of being trained (Factory, and Auto school in the late sixties))and teaching this topic every year since. JimN

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james rumph

03-30-2008 17:14:47

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Re: 10 ohm resister in reply to Janicholson, 03-30-2008 15:20:27

Question then how is mine differnt ? It has a brand new wireing harness , rebuilt generator, brand new voltage regulator . Everything is plug and play. The contact gap settings are in the factory service manual for the voltage regulator.

I got this info from a 60 year old I.H dealership.

I do understand what you are saying for a alt .

If my understanding of this is incorrect then i need to know ! I wired everthing per the instructions , which there isn't much to it.

I am amazed at the amount that goes threw the switch that is why it has such a high amp rating.

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Janicholson

03-30-2008 19:17:08

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Re: 10 ohm resister in reply to james rumph, 03-30-2008 17:14:47

The proper wiring is shown in these diagrams, I am not sure what you have, but I am convinced that the points in a regular voltage regulator have nothing to do with the tractor running when the ignition switch is off, there is no voltage to the coil! Take care, JimN

Bob M's marvelous diagrams

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160dan

03-30-2008 16:08:33

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Re: 10 ohm resister in reply to Janicholson, 03-30-2008 15:20:27

Thanks!!! I located a little Fluke 12B Mulitmeter and tested the diode (that I suspected was a diode anyway). I switched the meter to show an "M" and a symble looking like earmuffs. In that mode, reads 1.65 and nothing from the reverse. then with volts and a symble looking like the volume on this computer, It reads .466...??? is this a Diode and is it usable with the single-diretion of flow? Thanks for putting up with my lack of knowledge here. Dan

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Janicholson

03-30-2008 16:33:07

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Re: 10 ohm resister in reply to 160dan, 03-30-2008 16:08:33

The "headphone" symbol is for OHMS and is correct to use. A continuity check position on the meter will also work, it might have a little speaker, and a symbol of a diode on it. The meter is auto-ranging, this means it will read with the correct scale as needed. The volt position will do nothing (you were reading stray voltage from the leads and induction from near by wires, not the part, it has no volts to measure unless connected to something with volts in it. When reading the little M probably went away. and you are reading 1.5 ohms. When reading the other way, nothing would mean either it is open in that direction, non conducting, or has no resistance, full conducting. If the meter stayed with the same reading it had not connected, it was open (good), if it went to Zero through some numbers, it might not be a good diode. If it was a resistor, it would read the same both ways, and about 3 ohms or so (assuming it might be a ballast resistor for the coil).

Try it in the #1 terminal wire with the non conducting end toward the alternator terminal. Check it like this: Use the red lead of the meter as positive (it is) when it is showing nothing on the meter (in the Ohms position like you had it) with the black lead on the other end, mark that end for being towards the alternator. If it still keeps running turn it around, you cant hurt it, if it still keeps running, it is not a diode (at least it isn"t much of one). replace it with a 3amp 500 piv diode from radio shack, put the band end to the alternator. JimN

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David Goode

03-30-2008 09:49:15

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Re: 10 ohm resister in reply to 160dan, 03-29-2008 19:49:35

I had a promblem like that last year, If your tractor is converted to 12v negetive ground you need a diode in the line from the generator/ altenator to the distributer. -David Goode Coggon, IA

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Janicholson

03-30-2008 08:48:31

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Re: 10 ohm resister in reply to 160dan, 03-29-2008 19:49:35

John T and I agree on the reality.
If the item you took off is the ballast resistor that was installed by previous owner, and it is still, or now 12v, aaannnddd the same coil is used as before (12v with external resistor required) it may need to go back in the ignition circuit between the coil and ignition sw. The light, or diode you need is placed in the wire from the #1 terminal on the Alt. and the ignition sw. Any other place will not do it.
JimN

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james rumph

03-30-2008 04:56:11

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Re: 10 ohm resister in reply to 160dan, 03-29-2008 19:49:35

I put the 12 volt system on my Super M and had the same problem. If it still has a generator there is a voltage regulator.

Start your tractor and pull the throttle lever to the slowest rpm that it will go, now try and turn it off. If it does and will the point gap in the voltage regulator is to big.

I had the same problem and never knew there was a point gap in there that needs adjustment.

A diode is just a one way"gate" that will not let voltage feed back , probaly not what you need . When i had this problem i went back to ware the generator was rebuilt and they gave me a diode.

After a little research it was just a adjustment in the voltage regulator.

A ballest resister is used to cut voltage in 1/2 to the coil to keep it cool, doesn't effect performance at all .

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Janicholson

03-30-2008 08:58:34

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Re: 10 ohm resister in reply to james rumph, 03-30-2008 04:56:11

Please take no offense
His is converted to alternator
If the ignition switch is wired correctly on any tractor, it will stop when shut off. The setting of the regulator is not involved when the voltage is shut off to the coil.
He does need a diode, or idiot light in the wire we are discussing, there is regulator voltage on the #1 terminal after charging starts in the alternator. This voltage feeds back through the wiring to the coil keeping it running. The loght limits the current flow (and is a dash indicator for autos) a diode does the same job, but does not light up.
I'll disagree with the idea that a ballast resistor on a coil wont affect performance. If it is not there (and needed) it will burn out points, overheat the coil,and ruin it, and cause failures of ignition directly affecting performance, and drivability.

This is not a flame, it is just fact, JimN

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Brownie450

03-30-2008 04:30:15

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Re: 10 ohm resister in reply to 160dan, 03-29-2008 19:49:35

If it is a diode, it will register around 30 to 40 ohms in one direction & infinity with the leads reversed---if it is good. A resistor will measure the same with the leads reversed. If a diode measures 0 resistance both ways, it is shorted. If it measures infinity both ways, it is open. --Current can't get to the coil.

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John T

03-29-2008 20:46:29

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Re: 10 ohm resister in reply to 160dan, 03-29-2008 19:49:35

An ohm meter will tell what it is, good chance its a diode or maybe an in line resistor. Ohm it out real quick n you will have the answer. It would wire somewhere between the coils high input terminal or the ign switches IGN output terminal and the lil No 1 side alternator terminal...Ignition ballast resistors are also used when its a 12 volt tractor with a 6 volt coil, they are around 1 to 2 ohms or so. An idiot light could also be used for the alternators excitation instead of a resisotr or diode.

John T

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