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Wd45 12v conversion

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Dale

10-02-2002 15:16:07




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I am converting a WD45 to a 12v alternator system. I have read many of the articles concerning this conversion and it seems likes most of the confusion, (mine and others) concerning this conversion is related to the P1 terminal of the Delco alternator. It appears that there are several ways to make this connection,
1. P1 to accessory terminal on ignition switch with no resister or indicator lamp. (Duey's method)
2. P1 to ignition switch with indicator lamp in series between. (Bob M method)
3. P1 with diode in series between P1 and ignition switch. (Genesee method)
4. P1 with 10 ohm resistor between P1 and ignition switch.
My question is what are the differences or advantage of each method? Do you need to add resistance in the P1 circuit to make the alternator charge better or do all these methods simply provide a way of isolating this circuit when the engine is shut off. It appears to me that this P1 circuit just provides current to the alternator to start the excitation of the alternator.I would appreciate any information to help clear up this item. Thanks, Dale

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Jim In NC

10-03-2002 17:25:39




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 Re: wd45 12v conversion in reply to Dale, 10-02-2002 15:16:07  
I wired my tractor this way. I purchased a one wire alternator. Ran a 10 guage wire to the amp meter. On to the starter. I picked up current for the switch at the amp meter. It only took me a few minutes to wire the thing.



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Greg Ballantyne

10-03-2002 16:46:40




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 Re: wd45 12v conversion in reply to Dale, 10-02-2002 15:16:07  
What is the advantage to converting to 12 volt? Sure seems like a lot of trouble.



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Doug in OR

10-03-2002 19:34:07




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 Re: Re: wd45 12v conversion in reply to Greg Ballantyne, 10-03-2002 16:46:40  
The benefits? Gawd, I remember fighting with the old WD back when I was a kid. It was a typical Wisconsin winter day. Temperature: 0F. Windchill: -40F. The stinkin 6 volt system just wasn't enough to start the tractor. I eventually got it started, after ten minutes of torture on the hand crank.

12 volts is just more reliable. No more messing with the cutout. No more trying to find the proper charge rate with the light switch. When you pull the starter lever, the engine actually cranks over - at a nice brisk speed!

Difficult to install? Not at all. The hardest part of the whole installation is fabricating the mounting bracket for the alternator. And with just a few basic tools, a hacksaw and drillmotor, that isn't a big deal either. Don't be fooled by the discussions of "this way" and "that way" to make the installation. One way is just a variation of the other.

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Greg Ballantyne

10-05-2002 18:35:21




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 Re: Re: Re: wd45 12v conversion in reply to Doug in OR, 10-03-2002 19:34:07  
I was just wondering. I have heard about people converting to 12 volt, and have heard of 8 volt batteries in 6 volt systems for easier cold weather starting. My B is a six volt system, but my starter has worn the inside of the shaft nut so badly that the starter will not extend to engage the flywheel. But the tractor starts so easily with the hand crank that I have never fixed the starter. As long as the points are good (they need replacing about every year) it starts easily enough in cold weather with the hand crank. I guess I would want to keep it original in any case.

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Doug in OR

10-02-2002 18:48:59




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 Re: wd45 12v conversion in reply to Dale, 10-02-2002 15:16:07  
The resistance is more for protection than anything. The unit would work just fine if you merely jumped a wire from the ignition switch to the P1 terminal - except that the voltage developed on the P1 terminal after the alternator starts to charge will feed back and keep the engine from shutting off. All the mentioned systems work. I prefer a diode in the circuit somewhere - even if used with a lamp. This ensures that the voltage is zero when the ignition switch is shut off. A lower voltage will allow the engine to stop, but I don't like seeing the coil voltage floating like that. You can even use a double-pole switch to isolate the exciter from the ignition, and not use a resistor, diode, or lamp.

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Steve in N.J.

10-02-2002 18:47:43




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 Re: wd45 12v conversion in reply to Dale, 10-02-2002 15:16:07  
Dale,
One other thing I forgot to mention. When converting to a 12V system, I would recommend using a voltmeter in lieu of the ammeter. A voltmeter is more accurate and easier to see how and if the system is charging normally. Also, when you're generating more power into the original system, a voltmeter is a safer bet current wise.....
Steve B.



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Steve in N.J.

10-02-2002 18:39:55




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 Re: wd45 12v conversion in reply to Dale, 10-02-2002 15:16:07  
Dale,

All the ways that are listed for the #1 all do the same thing basically. Shut the power off after the engine is shut down. The #1 circuit is designed to "excite" the alternator by supplying power to the regulator in the alternator. Once the engine is running, the regulator excited, the alternator starts it's charging process. Because an early tractors wiring system does not utilize great amounts of power for accessories such as heater, wipers, etc like an automobile, other than lights (if equipped) and the ignition, (if it's distributor) that's about it. A resistor in the system as Steve mentioned actually helps the basic system to charge better because it's constently calling for just a little bit of power which keeps the alternator charging in a low RPM range. Depending on the system, after the alternator is in the charging mode and the key turned to the off position to shut the engine down, an alternator can generate enough power and "backfeed" the system through #1 through the ignition switch enough to keep the ignition circuit "energized" and the engine will continue to run with the key off. I install a diode in the exciter circuit in my harnesses to stop any backfeed that the alternator may put out after the engine is switched off. Other manufacturers use the same technic. Simple, but effective. I use the same technic in the wiring systems I do for Street Rods & Performance vehicles. Steve B.

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Duey (IA)

10-02-2002 17:59:25




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 Re: wd45 12v conversion in reply to Dale, 10-02-2002 15:16:07  
Dale, I found the main reason for the automotive switch with acc. or diode, was to seperate the coil wire from the alternator wire, to stop the back feed that allows the engine to keep running when the switch is turned off. The indicater light will create enough resistance to use the feed back current and in effect, allow the engine to be shut down. A light or resister will also start the charging at a lower RPM as Steve says. Basicly, more than one way to skin a cat! Duey

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Dale

10-02-2002 19:24:39




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 Re: Re: wd45 12v conversion in reply to Duey (IA), 10-02-2002 17:59:25  
Thanks for all the clarifications from everyone. I do appreciate the quick response on my question. I hope I can return the favor some day!
Dale



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steve

10-02-2002 17:26:46




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 Re: wd45 12v conversion in reply to Dale, 10-02-2002 15:16:07  
Dale, all are based on fact. Fist, the battery will discharge if you do not disconnect the #1 terminal from 12 volts when the motor is off. To do this you connect to the accessory terminal on the key, or the + terminal of the coil, or a toggle switch. Anyway to stop the flow of voltage backward from the battery thru the alternator to ground. Second, you want the alternator to charge properly. You could use a 12 volt excitation, but engine speed usually is about 2000 RPM to get the alternator to "kick in". A small resistor or light bulb or resistance wire in the circuit will cut the voltage to the excitation portion of the alternator and make it charge "better" in my opinion. I have installed a few delcos on tractors and use a 10 ohm -10 watt resistor from radio shack and the alternator will charge with the standard pulley at 500 RPM engine speed. I think this has a lot to do with it, others may argue. Car companies use a light bulb on the dash or a resistance wire in the harness to accomplish this. I got the 10 ohm resistor idea from a DELCO service test manual 20 years ago for testing on the bench. Works every time. reisitor is $1.

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