Is it the generator or ammeter

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debra nanlu

Junior Member
Hi guys,
Thanks again for all of the previous help. Once again I'm in need of your advice and direction. As you may remember, my husband is in a wheel chair so I'm now the chief mechanic around here. The problem:I put a charger on the Model A battery today but upon starting it I noticed that the ammeter does not show that it is charging. When I turn the lights on the ammeter shows a discharge. With the lights on, when I rev up the engine, the ammeter stays in the same discharge position. So, I assume the ammeter is good but the generator is bad and not charging. Before starting the car today I put a new cutout switch on the generator. The cutout was purchased from Burt's Model A. It was the good quality cutout that Burt's sells so I assume it is not the cutout. When I purchased the generator on ebay, the generator was supposedly rebuilt. I realize now that a lot of people selling on ebay are liars. Anyway is there some way of determining that the generator is bad before I buy another one? The supposedly rebuilt generator has less than 600 miles on it.
Thanks,
Debi
 
Flash the generator. Do this only if you are using an original type cutout (the cutout is a non-solid state or non-electronic). Take a pair of pliers and momentarily touch the handles across the 2 terminals of the cutout to polarize the field windings. You won't get a shock. This can be done with the engine running. See if it is charging now. If not try adjusting the charging rate. Remove the generator band and with a non-metalic stick (wood is good) push the brush that is closest to you toward the motor. The brush moves up and down decreasing and increasing the charging rate. Set your charge for 3 amps if you do mostly day driving. If you drive alot at night then set the amps to zero with the lights on. High charging rates will hurt your battery.
 
Like Ron said.. Also to check the generator quickly you can feed power to the generator and see if motors or at least tries to turn the engine over.. It depends on how tight the belt is as to just what the generator will do, if the belt is loose enough the generator will spin.. Your problem is probably just that you're in need of a 'flash',, its usually needed when the field coils have been removed.. I usually use a short jumper wire for that, but, pliers will work just fine.. It doesn't take any time, as soon as you see the 'spark' , its done..
 
DEbra: it might help if you posted where you are, there may be A owners near you who could assist, if not in person than on the phone, there may also be a club near you.
Paul in CT
 
Is the battery 6 volts?
Is the battery + ground?
Is the new cutout the diode type, or is it the stock electro-mechanical type?

As mentioned, do the easy thing first; jump across the two cutout terminals with a short wire (or pliers) for 1 second, then see if the generator charges.
 
Debra:

Paul in CT had an excellent suggestion. The local car clubs are very open to helping. They may not even be a Model A club. Our local Naper A's club makes a lot of "house calls" which we all enjoy immensely. We even keep our town Mayor's car in driving condition. Gar Williams
 
I would try two things in this order:
1. Disconnect the battery ground strap and sand the frame where the strap fastens and reconnect the strap.
2. Loosen (or remove) the fan belt. Hook one battery charger clamp to the generator output stud and the other clamp to a ground on the generator (the cutout mounting screw often works well). Turn on the charger. The generator should turn like a motor. If not, it needs rebuilding.
 
Though new to Model A's, my "other" life is working on Allis Chalmers farm tractors where I have run across this problem....do NOT assume that the cutout is good! I've installed at least one new out of the package and found that it didn't work. In addition to flashing the genny as described above, you could also install a jumper wire that takes the cutout out of the picture. A piece of wire connecting the two terminals on the cutout will do it. If you now get a charge indication on the ammeter, the cutout is bad. Just don't leave that wire in place after you test - the genny will act like a motor if the engine isn't running and THAT will certainly drain your battery if left that way! Good luck.
 
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