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Generator for A

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Grandpa love

08-04-2019 05:39:28

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I asked the other day and most folks said buy an alternator...... question was will this work on an A with a mag? Does it need a cut out relay,or voltage regulator? Thanks

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Bob M

08-04-2019 11:12:04

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 Re: Generator for A in reply to Grandpa love, 08-04-2019 05:39:28  
If it passes the "motor test" as JimN outlines it should work on your A.

You'll need to wire in the regulator (square box in the photo) for the generator to work.

It does NOT get wired to the magneto kill switch. The generator/regulator combination work completely independent of the ignition switch. When the generator reaches it's cut-in RPM the regulator will automatically connect it to the battery, and disconnect it again when the generator slows down or stops spinning.

Note the OEM generator does NOT use a fan - there is nothing missing off the pulley.

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08-04-2019 10:20:14

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 Re: Generator for A in reply to Grandpa love, 08-04-2019 05:39:28  
Yes but you have to have a switch to turn it on and off. The factory type switch for them had a double pole double throw set up where when you turned the switch of it ground the mag an at the same time turned off the generator system

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08-04-2019 12:17:05

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 Re: Generator for A in reply to old, 08-04-2019 10:20:14  
With respect!! The cutout relay in the VR shown is that switch. No extra switch is needed. Jim

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08-04-2019 12:30:54

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 Re: Generator for A in reply to Janicholson, 08-04-2019 12:17:05  
I have been told that the factory switch was set up with a high/low/off for the charging system

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08-04-2019 12:54:17

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 Re: Generator for A in reply to old, 08-04-2019 12:30:54  
The high Low Dim Bright 4 position switch is used with a cutout relay, and lights. The switch is always grounding the field in the generator. In the L position, the field current goes through a resistor to create a charge rate of about 3 to 4 amps which maintains the battery with no lights. The H D B positions are full field ground, creating enough extra current to replace charge the battery if started and stopped multiple times in one day, and to maintain the battery with the lights on.
The cutout disconnects the generator from the battery, isolating it so it cannot draw current when stopped. or going so slow that the charge voltage is less than the bat voltage. When the generator produced enough voltage (with only the residual magnetism in the iron of the gen field poles making the volts) to be more than the battery volts, it closes its contacts and connects the Armature to the battery. That Arm terminal on the gen is also where the field gets its voltage (or a third brush) to make the field energized to be grounded by (the voltage regulator in this case, or the light switch in the case of a 4 position switch. Jim

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08-04-2019 10:17:31

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 Re: Generator for A in reply to Grandpa love, 08-04-2019 05:39:28  
Looks like the cooling fan has been "lost".

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08-04-2019 08:27:58

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 Re: Generator for A in reply to Grandpa love, 08-04-2019 05:39:28  
Yes. Does it work? I would make sure it passes the motor test. Use jumper cables and ground the frame, then touch the A terminal. It should turn at a good speed. (not powerful, but nice) then while turning ground the field terminal with another jumper. If it slows down, the field is good. Don't run it more than a minute. Jim

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