The Ford Barn

Terry,NJ · 02-23-2014, 12:44 PM

All I know of electricity is Ohm's law E= I/R. But I don't understand it! So here goes, I put a new ammeter in the coupe. At first, everything worked fine! Then I was driving along and I noticed the the needle was centered on zero. No charge or discharge or it's just charging maybe 2 amps (trickle charge) Then it started working again! Viola! Hooray! I don't have to take this apart now! Then it goes back to zero and stays there for a while. The coupe always has enough juice to start, never had to jump it. But I'm only taking 5 mile rides to the flea market, What happens on a long drive? This is not working the way I know ammeters to work. (perpetual charge of varying amount) Is this correct for an A and I didn't notice? Or is it all wrong?
Thanks in advance, Terry

ford3 · 02-23-2014, 12:52 PM

are you using a regulator or a cut out, if a regulator the gen will charge till the battery reaches a certain voltage and then cut back to a few volts till the battery uses enough juice to excite the reg and let the gen charge some more, if a cut out it should show about 10 amps all the time, and about 2 amps with the lights on , this is at driving speed

Purdy Swoft · 02-23-2014, 12:59 PM

I agree with ford3 , depending on how the adjustable brush is set.

RonC · 02-23-2014, 02:18 PM

Quote:

Originally Posted by Terry,NJ

All I know of electricity is Ohm's law E= I/R.

[QUOTE=forever4;829165]Are you sure?[/Quote:]

E = IR

E = Energy
I = Current
R = Resistance

or Volts equals the Amps times the resistance in the circuit.

Tom Wesenberg · 02-23-2014, 03:53 PM

Repro ammeters may have a sticky needle. What was wrong with the original meter?

Repro or original, I always put a drop of heavy oil on each pivot for the needle.

I wouldn't be running with a 10 amp charge or you will be adding a lot of water to the battery and shorten the battery life. If I wasn't using my EVR, then I would set the adjustable brush for a 2 amp charge.

tbirdtbird · 02-23-2014, 10:00 PM

Sponsored Links (Register now to hide all advertisements)

possibly loose wire somewhere, also

Terry,NJ · 02-24-2014, 09:42 AM

Tom, I put my knuckle through the glass and mashed the needle. That glass is thin! So I ordered a new one from Mac's (made in China, naturally). I thought the old one was sticking. The charge rate when it's charging is about max 6-8. As I said, no failures on the road yet and the battery always seems healthy. Maybe I'm looking for trouble where none exists.
I think I'm using a Cut out. It's little round "Pot" on top of the generator. I've got all the wires hooked to the output side (Front) and none hooked to the input, from the generator (rear) Can it be wired wrong?
Terry

Joe K · 02-24-2014, 10:07 AM

See a typical Model A Wiring Diagram at http://www.webjunk.com/modela/wp-con...amcolor2sm.jpg

This includes the original "cut out" located on top of the generator.

There should be a wire coming "into" the cut-out, and one "leaving" the cut-out.

Possible variations on this theme go to a possible diode cut-out (which works the same but doesn't have the complication of a coil/contact arrangement) or replacement of the cut-out with a voltage regulator (which can add an additional input wire to send electricity back to the generator to energize the field of the generator - but not always. Some VRs have no additional connections and hook up similar to the cut-out with only an input and output lead. )

Either of the VRs may operate with a subtle "buzzing" which is its own contacts maintaining a precise 7.2 volts (or whatever) going to the battery. A cut-out in the mechanical-solenoid sense makes no sound except when the engine is shut off when you might hear a subtle "click" as the solenoid releases.

Appearance wise, most of these options appear about the same with the typically the "pot-shaped" cutout. A 1950s era VR I found on one of the Model A derelicts that came my way had a "square" box instead.

But you need to identify what you have before we can really help. The wiring diagram should help you a LOT.

Keep us posted.

Joe K

marc hildebrant · 02-24-2014, 10:28 AM

[QUOTE=RonC;829207]

Quote:

Originally Posted by forever4

Are you sure?[/Quote:]

E = IR

E = Energy
I = Current
R = Resistance

or Volts equals the Amps times the resistance in the circuit.

Ohm's law is V = IR
V = Volts
I = Current (Amps)
R = Resistance ( Ohms)

E is not correct as energy is measured in joules.

Marc

02-23-2014, 12:44 PM	#1
Terry,NJ Senior Member Join Date: Nov 2013 Location: Northern Bucks Co. Pa Posts: 632	generator troubles ? All I know of electricity is Ohm's law E= I/R. But I don't understand it! So here goes, I put a new ammeter in the coupe. At first, everything worked fine! Then I was driving along and I noticed the the needle was centered on zero. No charge or discharge or it's just charging maybe 2 amps (trickle charge) Then it started working again! Viola! Hooray! I don't have to take this apart now! Then it goes back to zero and stays there for a while. The coupe always has enough juice to start, never had to jump it. But I'm only taking 5 mile rides to the flea market, What happens on a long drive? This is not working the way I know ammeters to work. (perpetual charge of varying amount) Is this correct for an A and I didn't notice? Or is it all wrong? Thanks in advance, Terry

02-23-2014, 12:52 PM	#2
ford3 Senior Member Join Date: Oct 2012 Location: oroville calif. Posts: 1,453	Re: generator troubles ? are you using a regulator or a cut out, if a regulator the gen will charge till the battery reaches a certain voltage and then cut back to a few volts till the battery uses enough juice to excite the reg and let the gen charge some more, if a cut out it should show about 10 amps all the time, and about 2 amps with the lights on , this is at driving speed

02-23-2014, 12:59 PM	#3
Purdy Swoft Senior Member Join Date: May 2010 Location: Alabama Posts: 8,099	Re: generator troubles ? I agree with ford3 , depending on how the adjustable brush is set.

02-23-2014, 03:53 PM	#5
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: generator troubles ? Repro ammeters may have a sticky needle. What was wrong with the original meter? Repro or original, I always put a drop of heavy oil on each pivot for the needle. I wouldn't be running with a 10 amp charge or you will be adding a lot of water to the battery and shorten the battery life. If I wasn't using my EVR, then I would set the adjustable brush for a 2 amp charge.

02-23-2014, 10:00 PM	#6
tbirdtbird BANNED Join Date: May 2012 Location: inside your RAM Posts: 3,134	Re: generator troubles ? Sponsored Links (Register now to hide all advertisements) possibly loose wire somewhere, also __________________ '31 180A

02-24-2014, 09:42 AM	#7
Terry,NJ Senior Member Join Date: Nov 2013 Location: Northern Bucks Co. Pa Posts: 632	Re: generator troubles ? Tom, I put my knuckle through the glass and mashed the needle. That glass is thin! So I ordered a new one from Mac's (made in China, naturally). I thought the old one was sticking. The charge rate when it's charging is about max 6-8. As I said, no failures on the road yet and the battery always seems healthy. Maybe I'm looking for trouble where none exists. I think I'm using a Cut out. It's little round "Pot" on top of the generator. I've got all the wires hooked to the output side (Front) and none hooked to the input, from the generator (rear) Can it be wired wrong? Terry

02-24-2014, 10:07 AM	#8
Joe K Senior Member Join Date: Jul 2010 Location: Cow Hampshire Posts: 4,188	Re: generator troubles ? See a typical Model A Wiring Diagram at http://www.webjunk.com/modela/wp-con...amcolor2sm.jpg This includes the original "cut out" located on top of the generator. There should be a wire coming "into" the cut-out, and one "leaving" the cut-out. Possible variations on this theme go to a possible diode cut-out (which works the same but doesn't have the complication of a coil/contact arrangement) or replacement of the cut-out with a voltage regulator (which can add an additional input wire to send electricity back to the generator to energize the field of the generator - but not always. Some VRs have no additional connections and hook up similar to the cut-out with only an input and output lead. ) Either of the VRs may operate with a subtle "buzzing" which is its own contacts maintaining a precise 7.2 volts (or whatever) going to the battery. A cut-out in the mechanical-solenoid sense makes no sound except when the engine is shut off when you might hear a subtle "click" as the solenoid releases. Appearance wise, most of these options appear about the same with the typically the "pot-shaped" cutout. A 1950s era VR I found on one of the Model A derelicts that came my way had a "square" box instead. But you need to identify what you have before we can really help. The wiring diagram should help you a LOT. Keep us posted. Joe K __________________ Shudda kept the horse.