The Ford Barn

josephjamie · 04-29-2018, 09:42 AM

I just got this 1929 model A and it came to me hooked up with positive of battery hooked to generator. My generator has a round contact on it? What is that for? Also i dont think generator is charging plus when i put a new battery on with a positive ground the ammeter pegs to the left and gets extremely hot and smokes

jrelliott · 04-29-2018, 10:12 AM

The round thing on top of the generator is called a cutout. Its function is to allow the generator to charge the battery when the generator is working(car running) and to break the connection when the car is off as the generator will operate as a motor if you have the battery connected and the generator is not turning. The cut out has an input from the generator usually toward the front of the generator and another toward the rear of the generator. This output terminal of the cutout should have two connections , one two wires which go to the headlights and horn the other to the junction box on the firewall. If you do not know the history of the vehicle, sometimes this cutout has been replaced with a diode and if you reversed the polarity of the battery as you have stated will short the diode. If the cutout is shorted, then it will do what you are seeing.
Disconnect the two wires at the cut out and measure the resistance across the cutout terminals. If it is a short (0 ohms) then it is a problem. After correcting this, you will have to repolarize the generator after getting things reconnected.

Chuck Sea/Tac · 04-29-2018, 10:15 AM

If the positive of the battery goes to the generator, then the negative is on the ground or earth. So you’re hooking your battery up backwards. They came originally positive, but can’t be changed over. I would swap the battery and try that. The round thing on the Generator is a voltage cut out. It starts charging the battery at about 8 miles an hour or relevant Rpm.

josephjamie · 05-01-2018, 08:44 PM

I swapped battery to positive ground and found cutout welded together at contacts. Seperated contacts. Now when sometimes it cranks it backfires like crazy above an idle and has a lose of power. I cleaned carb and tightened all bolts. What causes this?

josephjamie · 05-01-2018, 08:45 PM

How do i repolarize generator and does it need to be running to do this

Floats · 05-01-2018, 09:01 PM

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JJ.
Many old cars were positive earth right up to the sixties. MG and even the early E Types were positive earth.. If memory serves, it had something to do with prevention corrosion or something. GOOGLE is your friend if you are really interested.
However, you have obviously caused some electrical damage which will not be undone by mearly swapping the + and - wires around. I think you need and auto electrician’s help.
The round thing on top have been expained as being a cutout, it is basically a first generation ‘voltage regulator’

Tom Wesenberg · 05-01-2018, 09:32 PM

Don't have the engine running, and jump a wire across the 2 cutout terminal for 1 second. It's now polarized to the battery ground polarity.

04-29-2018, 09:42 AM	#1
josephjamie Junior Member Join Date: Apr 2018 Posts: 3	1929 model A problem I just got this 1929 model A and it came to me hooked up with positive of battery hooked to generator. My generator has a round contact on it? What is that for? Also i dont think generator is charging plus when i put a new battery on with a positive ground the ammeter pegs to the left and gets extremely hot and smokes

04-29-2018, 10:12 AM	#2
jrelliott Senior Member Join Date: May 2010 Location: Pine, AZ Posts: 794	Re: 1929 model A problem The round thing on top of the generator is called a cutout. Its function is to allow the generator to charge the battery when the generator is working(car running) and to break the connection when the car is off as the generator will operate as a motor if you have the battery connected and the generator is not turning. The cut out has an input from the generator usually toward the front of the generator and another toward the rear of the generator. This output terminal of the cutout should have two connections , one two wires which go to the headlights and horn the other to the junction box on the firewall. If you do not know the history of the vehicle, sometimes this cutout has been replaced with a diode and if you reversed the polarity of the battery as you have stated will short the diode. If the cutout is shorted, then it will do what you are seeing. Disconnect the two wires at the cut out and measure the resistance across the cutout terminals. If it is a short (0 ohms) then it is a problem. After correcting this, you will have to repolarize the generator after getting things reconnected.

04-29-2018, 10:15 AM	#3
Chuck Sea/Tac Senior Member Join Date: May 2010 Location: Between Seattle & Tacoma Posts: 2,354	Re: 1929 model A problem If the positive of the battery goes to the generator, then the negative is on the ground or earth. So you’re hooking your battery up backwards. They came originally positive, but can’t be changed over. I would swap the battery and try that. The round thing on the Generator is a voltage cut out. It starts charging the battery at about 8 miles an hour or relevant Rpm.

05-01-2018, 08:44 PM	#4
josephjamie Junior Member Join Date: Apr 2018 Posts: 3	Re: 1929 model A problem I swapped battery to positive ground and found cutout welded together at contacts. Seperated contacts. Now when sometimes it cranks it backfires like crazy above an idle and has a lose of power. I cleaned carb and tightened all bolts. What causes this?

05-01-2018, 08:45 PM	#5
josephjamie Junior Member Join Date: Apr 2018 Posts: 3	Re: 1929 model A problem How do i repolarize generator and does it need to be running to do this

05-01-2018, 09:01 PM	#6
Floats Senior Member Join Date: Dec 2013 Location: Mossel Bay, about 300km from Cape Town Posts: 530	Re: 1929 model A problem Sponsored Links (Register now to hide all advertisements) JJ. Many old cars were positive earth right up to the sixties. MG and even the early E Types were positive earth.. If memory serves, it had something to do with prevention corrosion or something. GOOGLE is your friend if you are really interested. However, you have obviously caused some electrical damage which will not be undone by mearly swapping the + and - wires around. I think you need and auto electrician’s help. The round thing on top have been expained as being a cutout, it is basically a first generation ‘voltage regulator’ __________________ Regards Chris Cape Town 28 Model A RPU, 29 Chevy Phaeton, 67 E Type FHC, 67 250SL Pagoda, 83 911 SC

05-01-2018, 09:32 PM	#7
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: 1929 model A problem Don't have the engine running, and jump a wire across the 2 cutout terminal for 1 second. It's now polarized to the battery ground polarity.