The Ford Barn

garyaodell · 04-07-2013, 06:13 PM

I have a question. When I first got my Model A three and half years ago it would burn out lights in just a few seconds, using a volt meter I discovered the generator was putting out 1400 volts. My question is how can 6 volt excited generator put out that kind of voltage?
This voltage was at idle and the amperage was about 16 amps.

BrianM · 04-07-2013, 06:25 PM

Chances are you were using a digital type multimeter, which is quite susceptible to noisy voltages. The sparking at the commutator brushes probably caused this erroneous reading. Try using an old fashioned analog (dial type) meter for a real reading.

ford3 · 04-07-2013, 06:28 PM

an unregulated generator can put out a tremdous amount of voltage,check if third brush is adjusted correctly

garyaodell · 04-07-2013, 06:31 PM

I was using a digital meter. It would peg a 20 & 200 v and was a very steady reading at 1400 V. thankyou for your reply.

Willie Krash · 04-07-2013, 07:11 PM

If the generator does not "see" a battery it will go very high. That's when you get to see the field coils explode in the barrel and crispy fried.

Tom Wesenberg · 04-07-2013, 07:43 PM

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An unregulated Model A generator can put out up to 40 volts on my test stand. That's why clean and tight connections all the way to the battery are important. A voltage regulator is even better though.

Tom Endy · 04-07-2013, 07:56 PM

One of the reason the generator will not see the battery and allow the voltage to spike up is if the ground on the battery is not making good contact with the frame. The most overlooked electrical connection on a Model A is where the battery ground strap bolts to the frame. It is out of sight, out of mind, and difficult to get to.

Remove the floor board, remove the battery, and unbolt the ground strap from the frame. Wire wheel the ground strap and the nut and bolt. Take a small disk sander and mount it in a drill motor and grind off 80 plus years of rust and crud (or powder coating and paint) on the boss on the frame where the ground strap mounts.

It is suggested you do this about every 10 years.

Tom Endy

04-07-2013, 06:13 PM	#1
garyaodell Member Join Date: Mar 2013 Location: Idaho Falls, Id Posts: 31	garyaodell I have a question. When I first got my Model A three and half years ago it would burn out lights in just a few seconds, using a volt meter I discovered the generator was putting out 1400 volts. My question is how can 6 volt excited generator put out that kind of voltage? This voltage was at idle and the amperage was about 16 amps.

04-07-2013, 06:25 PM	#2
BrianM Member Join Date: Aug 2012 Location: Gwinn, MI Posts: 46	Re: garyaodell Chances are you were using a digital type multimeter, which is quite susceptible to noisy voltages. The sparking at the commutator brushes probably caused this erroneous reading. Try using an old fashioned analog (dial type) meter for a real reading.

04-07-2013, 06:28 PM	#3
ford3 Senior Member Join Date: Oct 2012 Location: oroville calif. Posts: 1,453	Re: garyaodell an unregulated generator can put out a tremdous amount of voltage,check if third brush is adjusted correctly

04-07-2013, 06:31 PM	#4
garyaodell Member Join Date: Mar 2013 Location: Idaho Falls, Id Posts: 31	Re: garyaodell I was using a digital meter. It would peg a 20 & 200 v and was a very steady reading at 1400 V. thankyou for your reply.

04-07-2013, 07:11 PM	#5
Willie Krash Senior Member Join Date: Jan 2012 Location: Phoenix, Oregon Posts: 661	Re: garyaodell If the generator does not "see" a battery it will go very high. That's when you get to see the field coils explode in the barrel and crispy fried. __________________ Mike Stitt "A business that make nothing but money is a poor business." -Henry Ford

04-07-2013, 07:43 PM	#6
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: garyaodell Sponsored Links (Register now to hide all advertisements) An unregulated Model A generator can put out up to 40 volts on my test stand. That's why clean and tight connections all the way to the battery are important. A voltage regulator is even better though.

04-07-2013, 07:56 PM	#7
Tom Endy Senior Member Join Date: May 2010 Location: Southern California Posts: 3,168	Re: garyaodell One of the reason the generator will not see the battery and allow the voltage to spike up is if the ground on the battery is not making good contact with the frame. The most overlooked electrical connection on a Model A is where the battery ground strap bolts to the frame. It is out of sight, out of mind, and difficult to get to. Remove the floor board, remove the battery, and unbolt the ground strap from the frame. Wire wheel the ground strap and the nut and bolt. Take a small disk sander and mount it in a drill motor and grind off 80 plus years of rust and crud (or powder coating and paint) on the boss on the frame where the ground strap mounts. It is suggested you do this about every 10 years. Tom Endy