The Ford Barn

pawillie · 05-13-2024, 06:54 PM

I installed rebuilt generator and new amp meter in my 29 A. Set third brush in generator 1/3 down. When checking if charging at the battery, the number's on my multimeter goes crazy, just flickers. Also, amp meter needle doesn't move. Thanks for help.

ndnchf · 05-13-2024, 08:24 PM

You must use an analog meter. What kind of cutout are you using? Did you install it backwards? Post some good clear photos of your generator so we can see.
Steve

Mike1291 · 05-14-2024, 03:59 AM

Your car may also not charge at idle if your brush is only 1/3 down.Try going to a fast idle or just rev the engine slowly to see how much charge you are putting out at different RPM. The charge rate will cap out at a certain RPM, and for me that's somewhere around 2000. You want no more than 5 amps for short daytime drives, and around 2 amps if you drive for long distances.

Synchro909 · 05-14-2024, 04:28 AM

IMO, those digital meters are about as useful as fly screen on a submarine. Throw them in the trash.

Badpuppy · 05-14-2024, 08:08 AM

Check for good ground connection between generator and battery.

Will N · 05-14-2024, 09:34 AM

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It also might take a little running time for the new brushes in the rebuilt generator to fully seat against the commutator. Until they run in and make full contact you could see erratic numbers on the meter.

ndnchf · 05-14-2024, 09:51 AM

If it was properly rebuilt, the brushes should have been sanded in to fit the commutator. I do this on every generator I rebuild.

rotorwrench · 05-14-2024, 10:40 AM

I have digital and analog meters and use both. My Fluke digital was purchased to adjust voltage output on aircraft 24-volt systems so they would charge at 28-volts. The fluke was the most accurate one I could get 30 years ago and it works fine on alternator and starter generator systems. If his meter is fluctuating then there is likely something wrong.

I would polarize the field pole shoes, Insure that the cut out works, and try it again. A test of the amp meter can be done by hand cranking the engine till your sure the points are closed. If the coil is wired to the load side then switching the ignition on with points closed will show a discharge of at least 3-amps. Also insure the battery connections are good and tight.

05-13-2024, 06:54 PM	#1
pawillie Junior Member Join Date: May 2016 Posts: 9	charging I installed rebuilt generator and new amp meter in my 29 A. Set third brush in generator 1/3 down. When checking if charging at the battery, the number's on my multimeter goes crazy, just flickers. Also, amp meter needle doesn't move. Thanks for help.

05-13-2024, 08:24 PM	#2
ndnchf Senior Member Join Date: May 2012 Location: Fredericksburg, Virginia Posts: 793	Re: charging You must use an analog meter. What kind of cutout are you using? Did you install it backwards? Post some good clear photos of your generator so we can see. Steve

05-14-2024, 03:59 AM	#3
Mike1291 Member Join Date: Dec 2023 Location: Rhode Island Posts: 69	Re: charging Your car may also not charge at idle if your brush is only 1/3 down.Try going to a fast idle or just rev the engine slowly to see how much charge you are putting out at different RPM. The charge rate will cap out at a certain RPM, and for me that's somewhere around 2000. You want no more than 5 amps for short daytime drives, and around 2 amps if you drive for long distances. __________________ Early 1931 Coupe Member of the Little Rhody Model A Club (MAFCA & MARC)

05-14-2024, 04:28 AM	#4
Synchro909 Senior Member Join Date: Jun 2014 Location: Melbourne, Australia Posts: 7,564	Re: charging IMO, those digital meters are about as useful as fly screen on a submarine. Throw them in the trash. __________________ I'm part of the only ever generation with an analogue childhood and a digital adulthood.

05-14-2024, 08:08 AM	#5
Badpuppy Senior Member Join Date: Dec 2017 Location: Guthrie, OK Posts: 1,153	Re: charging Check for good ground connection between generator and battery.

05-14-2024, 09:34 AM	#6
Will N Senior Member Join Date: Jul 2010 Location: Pennsylvania Posts: 1,113	Re: charging Sponsored Links (Register now to hide all advertisements) It also might take a little running time for the new brushes in the rebuilt generator to fully seat against the commutator. Until they run in and make full contact you could see erratic numbers on the meter.

05-14-2024, 10:40 AM	#8
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,503	Re: charging I have digital and analog meters and use both. My Fluke digital was purchased to adjust voltage output on aircraft 24-volt systems so they would charge at 28-volts. The fluke was the most accurate one I could get 30 years ago and it works fine on alternator and starter generator systems. If his meter is fluctuating then there is likely something wrong. I would polarize the field pole shoes, Insure that the cut out works, and try it again. A test of the amp meter can be done by hand cranking the engine till your sure the points are closed. If the coil is wired to the load side then switching the ignition on with points closed will show a discharge of at least 3-amps. Also insure the battery connections are good and tight.