VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 amp gauge is it overcharging

Guys and Dolls
my amp meter reads 12 at idle but goes to 20 at higher rpm, is that too much ?
Ken 45145

not expert on that year but I thought I would put my two cents in. My owners book on the 1936 says not to pay attention to the amp meter when driving except when it is on discharge. Then only if after a long while if it does not go back to full charge to check it out. I may be wrong but the cut out only works in the "on" or "off" possition. It does not regulate gradualy more power or less. I think.

Terrill
thank you very much for your 2 cents. I recently tightened fan belt and wondered if after reading page 60 in instructions "small amount of slack in it, just enough tension to keep belt from being thrown off pulley" that had anything to do with it as well as wondering if this has something to do with my ignition problem.
fun in the sun
Ken 45145

Do not think that would be related...unless the system has a mashed wire somewhere. Check to see if all insulation on wire is "O.K." where passes thru fire wall or clips.Make sure all connections are not loose...I've had boldt back out on mine because I've got gravel road to run on here. Then check the eye on the end of wires. May not have got crimped on good or in my case it worked loose on vibrations over time and broke at where the wire went into the eye. I fixed mine by puting a new end on..can get them at most local places or on order...

There was a thread on here a while ago where 8A was mentioned as being the sweet spot, but I can't recall at what speed. 20A sound way too high, no matter the speed.

Shawng
got that thread complete is for 29, can the 1927 be adjusted cannot find this info in the instructions or service news
Ken 45145

I am going to say yes, because my 28 service manual waffles between the AA and the AB. I believe we have the same genny.

20 amps is way too much. Should be around 12 when driving down the road.

ok
If I check voltage coming from generator on generator side of voltage regulator and it shows 18 volts is that ok. if I check voltage on other side of voltage regulator it should read less say 8 volts, if I read 18 volts the regulator is nfg. I am not very good with electrical so appreciate any comments.
Is there a more comprehensive Chevy service manual for the 1927 Capital AA. I have instruction book and service news for 1927.

Thanks
Ken 45145

Regulator? A voltage regulator was not used in 1927. At any rate, the voltage output of the generator itself should be around 8.2 to 8.5 volts.

Ken, are you mistaking the cut out switch on the top of the genny for a regulator?

Shawng
perhaps so, I assumed the item on top of generator was a regulator. So this must be a cutoff device. I understand that generators can output high voltage that would be controlled by some device. Anyway it appears that I have 18 volts coming out of generator, will check again in morn, is that considered ok for 1927 ?
Thanks
Ken 45145

Junkyard Dog
Thank you for you help, I will try to adjust the third brush as directed in the prior post.
Thanks again
any additional comments appreciated
Ken 45145

Ken, only test the voltage at the terminal connected to the wire going to the car and not the terminal on the other side of the genny going into the cutoff. at the end of the day the only voltage that matters is what the car sees. if this is in the correct range, one can assume the genny is working properly. You have to think simple and treat it like a "black box" with one output. If the output is correct, you don't need to worry or care about what goes in inside. In this case, ignorance is bliss!

Adjust the brush for current output, and be doen with it and move on to the next broken thing.

Isn't that how this hobby works???

Actually, the output voltage from the generator itself should be considered also since the cut-out is only an "off-on" switch and it has nothing to do with cutting down the output of the generator The direct output of the generator is important as well.

I just tested a 1929-32 model 943-J six volt generator (1927 - 1928 would be about the same) on my Weidenhoff generator test bench and at 1,700 RPM generator speed (which is the test rpm for this generator) the max. direct output of the generator was 9.7 volts. At the battery the voltage reading was 8.3 volts. The voltage readings were taken with a Simpson digital meter. The difference between the direct output of the generator and the actual voltage getting to the battery was only 1.4 volts.

It is important to not have the generator over charge. If it does you will tend to boil the battery dry on long trips and you might also burn out the generator. I learned this $150 lesson last year.

Arend
thank you for the guidance. Well just got back from the slave pit and now its my time so I ran out and located that small round head screw locking the third brush. For those of you reading this in the future it is easy. Well I moved it both directions but pushing it towards the engine reduced the amp gauge reading from 20 to 8-12 mostly 9. If you look at the 5-22-09 posting by CJP's 29 Generator charge setting, you will find narrative on adjustment. I do not trust my multi meter but it may have indicated 6-7-8 volts at battery. Battery is bubbling slightly. As I have adjusted it to the limit possible to achieve the results is that some indication of some problem?
Thank you Shawng and also that Old Dog the Junkyard one for all the help also Terrill. Please post responses.

So, after the adjustment what is the direct voltage output on the generator lead that goes to the cut-out?

Junkyard Dog
average 9 volts 8-9 situation. however when I turn lights on amps goes to 0 maybe -1 unless more than idle.

thought, could the 20 amp and 20 volt overcharge have been the cause of my intermittent coil problem? too much load on system?

thanks all
Ken 45145

nope
just went for drive 10 amp charge shut off will not start again hot no spark primary circut ok
secondary no spark

Ken

If indeed the voltage was high, you might have cooked the coil and/or the points. Check both.

Shawng
thanks
Ken 45145

will try another coil (#3)

well
car cooled off and then it started right up, Chipper poured water on his coil to cool I thought about it but did not. Will install coil # 3
Ken 45145

With a standard 3rd brush generator,there is no control over the output voltage of the generator voltage.That is why most "6 volt" globes are rated at 6-8 volts.With the standard 3rd brush generator,the only control you have is the actual current output of the generator armature.
There are 6 possibilities for excessive voltage in the system.
(1)The cutout airgap settings are incorrectly adjusted

(2)The voltage at which the cutout points close
connecting the the generator output to the
is incorrectly set

(3)There is a loose connection somewhere in the
charging circuit,causing the generator
to "think" it needs to put out more
volts.This could be a simple as a loose
screw at the cutout itself,or a loose
connection at or in the ammeter.

(4)A bad earth lead connection

(5)A bad power lead connection

(6)Battery on its way out
These symptoms of high output voltage would cause excess burning of the ignition points,cause the coil(it MUST be a coil for a non-resistor ignition system)to badly overheat and possibly short out or totally burn out,and the life of all light globes to be severely shortened.
As Ken has pointed out in my earlier post,a good charge rate for a std 6 volt 3rd brush generator in normal daytime running would be from 6 to 8 amps max.