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generator from 6 to 12

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Jim in PA

12-14-2007 14:29:22

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How involved is it to change the generator on a 46 A from 6 to 12 volt. The generator is already apart so I figured now is a good time to convert. thanks in advance for your input, Jim

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Tom 43

12-14-2007 17:58:56

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Re: generator from 6 to 12 in reply to Jim in PA, 12-14-2007 14:29:22

If you use a 6 volt generator with a 12 volt regulator you will burn the regulator contacts if you use the tractor very much. Since the 6 volt fields have half the resistance of 12 volt fields you will be subjecting the regulator contact points to twice the current flow they were designed for.

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John T

12-15-2007 06:20:37

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Re: generator from 6 to 12 in reply to Tom 43, 12-14-2007 17:58:56

Right On, figuring the genny (assuming same pulley size) will turn at the same speed, in order to increase its output requires more field current amps (i.e. more heat). The ones I converetd (NOT engineering correct but worked) that way never had any problems but if the VR relay contacts were marginal or carboned/burned or especially were running at reverse polarity they were designed for it could sure fail prematurely. I still think he would be better off to get a good used or a rebuit 12 volt n be done with it cuz fields n armatures for a engineering correct conversion arent cheap grrrrr rrrrr

Fun discussion yal take care

John T

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Rusty Wheel

12-14-2007 16:43:54

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Re: generator from 6 to 12 in reply to Jim in PA, 12-14-2007 14:29:22

I converted a 40-W to 12 volt negative ground in October. It cost about $140.00. This included a 100 amp alternator, a 12 volt battery, volt meter and light bulbs. I also installed a key ingition switch. This eliminates the voltage regulator cause it's built in the alternator. The starter doesnt care as long as you don't run the starter motor for too long a time to cause it to heat up. It was really simple to wire, made a really neat job and made a vast improvement in the tractor. I'm wanting to do a 1959 cub, but I haven't found an alternator that will fit under the hood where the generator is. I'm wondering if an alternator from a 154 low-boy will fit? Merry Christmas..... ...RW

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Mike M

12-14-2007 17:01:41

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Re: generator from 6 to 12 in reply to Rusty Wheel, 12-14-2007 16:43:54

With all the small engine foreign cars and compact tractors you should be able to find very small alt. but just cause they are small doesn't mean the price will be.

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Mike M

12-14-2007 17:01:34

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Re: generator from 6 to 12 in reply to Rusty Wheel, 12-14-2007 16:43:54

With all the small engine foreign cars and compact tractors you should be able to find very small alt. but just cause they are small doesn't mean the price will be.

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J. Mark Krcmarik

12-14-2007 16:26:24

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Re: generator from 6 to 12 in reply to Jim in PA, 12-14-2007 14:29:22

Does this also work on other models of this era? The voltage regulator is nothing more than a relay to switch from start to running. Does this mean that any 12 volt relay would work? I have a brand new 1951 MI that has to work for a living and the 12 volt parts, batteries are readily available. Also, can the 12 V system be converted to a negative ground?

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John T

12-15-2007 06:10:33

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Re: generator from 6 to 12 in reply to J. Mark Krcmarik, 12-14-2007 16:26:24

Mark, The older models plus the M didnt use a Voltage Regulator but instead a 2 wire Cutout Relay while the light switch regulated the gennys output. The cutout relays on those latch in at a certain voltage and likewise drop out at a certain lower voltage and would be designed for a 6 or 12 volt application.

YES either a 6 or 12 volt genny can work at EITHER polarity once its Polarized.

John T

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J. Mark Krcmarik

12-17-2007 07:50:09

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Re: generator from 6 to 12 in reply to John T, 12-15-2007 06:10:33

Yes, I remember about the switch being the rate controller. At this point, the ampmeter does not move off 0 amps, which leads me to believe that the genny does not have any output. Could the gauge be busted?

Can you explain the term "polarized"?

Your help is greatly appreciated.

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Gerald J.

12-14-2007 20:19:50

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Re: generator from 6 to 12 in reply to J. Mark Krcmarik, 12-14-2007 16:26:24

The voltage regulator is MORE than a relay. There are typically two or three relay type devices in the case, but one has current and voltage windings to be current direction sensistive to open when the current flows into the generator. That's the cutout.

The next is the voltage regulator that pulls in to lower the field current when the gnerator armature voltage reaches the regulated voltage, about 14 volts for a 12 volt system. The standard 12 volt relay pulls in at about 8 to 9 volts so it has strong contact pressure with 12 volts applied. So if hooked as a regulator, it would regulate at that lowered pull in voltage.

Then sometimes there is a third relay like device that is current sensitive and when it detects too much generator armature current, it pulls in to backs off the field current to protect the generator armature.

The voltage and current regulator "relays" are allowed to vibrate and so with the inductance of the field coils to give a fairly steady voltage out of the generator.

Gerald J.

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John T

12-14-2007 15:22:04

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Re: generator from 6 to 12 in reply to Jim in PA, 12-14-2007 14:29:22

If a shop did it they would probably change the field windings and maybe the armature buttttt ttt that would get fairly expensive, ESPECIALLY if they changed out the armature, probably cheaper to get a good used or rebuilt 12 volt genny then to do a conversion. ORRRRR RRR I have done nothing n just changed to a 12 volt Voltage Regulator n they worked. Im NOT saying they set the world on fire at any high charge rate or thats engineering correct ONLY that it can work. A genny dont know exactly what it is really, if it turns faster (like Gerald mentioned via say a smaller pulley) or you pump more current through its field windings (kind of what the VR controls) its output increases. Polarize it when youre done n see what happens

John T

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jasper t

12-14-2007 14:33:42

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Re: generator from 6 to 12 in reply to Jim in PA, 12-14-2007 14:29:22

from what I've been told all you need is a 12V regulater. thats what a rebuilder told me.

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Gerald J.

12-14-2007 15:08:26

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Re: generator from 6 to 12 in reply to jasper t, 12-14-2007 14:33:42

Also helps to turn it faster.

Gerald J.

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