Generator Third brush Adjustment
- Thread starter Karl
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petehoovie
Well-known member
Were you able to count three brushes? With the generator mounted and the cover removed, the third brush will be visible toward the top of the armature somewhere between 9 and 11 o'clock. It should move from about 9 o'clock to 11 o'clock as viewed from the rear of the generator....
In looking at the pics, the one easily seen in the photo is the 3rd brush. It rotates about the centerline of the armature. With a wooden dowel or just a stick, push against the post in the pic. It should move in both directions, ( "up and down
It takes a little bit of force to move it. You are on your way.
just an opinion
It takes a little bit of force to move it. You are on your way.just an opinion
Hi there, as stated by Pete the third brush is near the top of the generator with gen mounted on the V8 engine. Also the third brush is normally somewhat thinner in cross section (thickness) than the other two brushes. The brush will rotate around the circumference of the commutator by pushing on the brush holder post and not on the brush itself. Sometimes they are tight and a LITTLE tap is required. Move brush with generator rotation to increase charge amps and against rotation to reduce charge amps. Maximum safe amps setting for a 1934 generator is 14 amps but for normal daytime driving this is way to high. About 5 amps showing on your dash ammeter when running in daytime (no lights on) is plenty high enough. Remember this 5 amps showing on the ammeter is actually a generator output of around 8 amps allowing for the ignition coil current draw. This setting will not cover all the current draw of your headlights so if doing much night driving (say more than an hour) the brush would have to go up to 14 amps. If left at i4 amps in daytime with lights off then the battery will be overcharged. A "FUN PROJECTS" brand round voltage regulator which replaces the original cut out on top of the generator will overcome this drawback. You must order for POS or NEG ground regulator to suit your electrical system. Regards, Kevin.
Ian NZ
Well-known member
Adjusting the third brush which is on top of the generator opposite the oil cap with the dash ammeter is not a good idea, it should be adjusted separately or by an auto electrician on a their machine to 10 amps. I have fitted a " Fun projects" regulator which works very well on my 32 generator and set it at no more than 14 amps on the dash ammeter as they recommend, and I have found the generator was getting extremely hot, and I have just about burnt it out, because those 32 generators do not have any fan blades on the pulley and there are no vents in the casting on front of the generator, so at the moment it is at the auto electrician being set a 10 amps as I do not do much night driving anyway.
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MGG
Senior Member
I set the third brush on my 1934 generator, also equipped with a Fun Projects regulator, to the letter of their instructions. I have a good battery (6-volt) re-built generator, and a very accurate ammeter also from Fun Projects. After starting the engine, the generator will put out about 6-7 amps as it is replacing the battery starting charge. After about 5 minutes the charge is replaced and the generator charging rate decreases to a steady 2 amps. If I turn on the headlights, the regulator allows the charge rate to go up accordingly so the generator is still putting back about 2 amps +/-. This charge rate should never cause a problem for the generator or battery.
fourfords
Senior Member
I'm surprised no one volunteered exactly HOW to adjust the third brush. Standing on the drivers side of the car, remove the band around the generator. I take a small wooden dowel and gently tap the third brush DOWN a bit to raise the voltage output. Gently tap it up to decrease the voltage. If you have a six volt system with no other accessories, and after you make your estimated adjustment, start your car and look at the ammeter. When it is flat at zero when you have your headlights on, you are Good to go. Don't forget to apply a couple drops of oil to the oil ports on the top front and rear of the generator every once in a while.
fourfords, Im not sure but Karls ford might be a right hand drive car being in NZ. So therefore your drivers side up/down instruction on the third brush would be arse about would it not ? The ford owners handbook and service manuals always say to adjust the third brush with rotation of gen to increase output and against rotation to decrease charge rate. Also back in the day and even today most people don't own a proper automotive generator test set with a quality amp gauge and voltmeter to connect to the generator to set the third brush. Nor do they have access to an auto electrical repair shop with a test bench. The best they can do is use the dash ammeter which only gives an approximate reading but is usually good enough. Also the 32 and 33 ford V8 generators had no cooling openings in the front or back of the generator and no cast in fan blades on the gen pulley so a maximum charge rate of 10 amps is all they can safely charge. The 34 ford V8 was the first year of the air cooled generators which had a safe output of 14 amps. They will do more amps but 14amps is a SAFE maximum with no overheating. Regards, Kevin.
petehoovie
Well-known member
[FONT=arial,helvetica,verdana] T[FONT=arial,helvetica,verdana]hi[/FONT]s, from Supereal as posted on the EF[FONT=arial,helvetica,verdana]V8[/FONT] Club site
-- 04-11-2010 @ 10:36 AM[/FONT] [FONT=arial,helvetica,verdana]
"You can adjust the generator by placing a voltmeter across the battery posts, and set the 3rd brush to show just above 7.5 volts at a fast idle. If you drive at night, which most of us don't, adjust with the lights on. Otherwise, leave them off. Most ammeters are like a weathervane. It shows the direction of the flow, but not velocity (current). As for polorizing, it isn't always necessary. If the generator has output, you don't need to do it."
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-- 04-11-2010 @ 10:36 AM[/FONT] [FONT=arial,helvetica,verdana]
"You can adjust the generator by placing a voltmeter across the battery posts, and set the 3rd brush to show just above 7.5 volts at a fast idle. If you drive at night, which most of us don't, adjust with the lights on. Otherwise, leave them off. Most ammeters are like a weathervane. It shows the direction of the flow, but not velocity (current). As for polorizing, it isn't always necessary. If the generator has output, you don't need to do it."
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Brian
Well-known member
I love three brush generators; they are so simple. However, the concept seems to freak people out these days. Tighten up the cover band sufficiently that it will stay in place, but can slide back to reveal the cutouts in gene case. Then, when darkness is approaching, and you're still out on the road, it is easy to pull off the road, open hood, slide back cover, move brush down, slide cover back, close hood, and carry on driving. Takes longer for me to type it than to perform it. You don't even need to switch off the engine!
Once you become familiar with the two positions you'll need to position the brush, you'll be able to do it blindfolded!
Once you become familiar with the two positions you'll need to position the brush, you'll be able to do it blindfolded!
Ian NZ
Well-known member
As the three brush generator on my 1932 has a mount on the back to the manifold I cannot remove the back cover, I used to have a short bit of an artists wooden brush and insert it into the holes number 1 & 2 on the back cover to rest against the brush holder to move it for more charge on hole 1 and less charge on hole 2. The photo shows the large wooden brush on hole 1 on the generator removed from the car.
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petehoovie, I do not agree with your volt meter method of adjusting the third brush and neither does the ford shop manuals. The third brush system has no voltage control as such and even if you set it at 7.5 volts at the battery you still don't know what the amps are doing. If it is a two brush gen with a separate voltage and current control regulator then you set the voltage and current outputs with the regulator. Correct way to set the third brush type is by using an ammeter and limit the generators safe maximum amps output to the recommendation OR LOWER as required by your vehicles loads. Being doing it this way for more than 50 years Pete. Just make sure the amps charging don't exceed the generators safe maximum at any time. Regards, Kevin.
petehoovie
Well-known member
@koates - Re-read my post. I quoted 'supereal's' method...
Karl
Well-known member
Thanks to all replies . I found the the third brush it was just so gummed up on the plate that it wouldn't move- it does now . My car being an early 34 and an export model is fitted with the early post generator with no cooling fins (ie 1933) I have an oval cutout which John Reagan aka FunProjects has altered for me -as my car has a radio I believe this cutout is correct. Of course to fit it I need the later 2 wire generator which I suspect is a better generator to use as Ian has eluded to with less chance of over heating. I will keep all the original bits to reinstall so I can take it back to stock if desired . There seem to be quite a few early 1934 differences! Also I suspect overseas cars used up the last of the previous models parts -Karl
Capt Kirk
Well-known member
Reviving an old thread. I may be having a similar situation as has been discussed above. I just checked voltage at the cutout. It's 7.5 at idle and goes to 9 with the engine spooled up. My amp gauge shows positive charge at idle but it's near the 0 line. When driving, it stays at 10 amps charging. It's a 3 brush generator with a Ford Script cutout from Macs (10 years old by now). I also have an Optima installed on its side. As I read the above thread, I'm getting some mixed messages so I have to employ some reasoning.
It seems to me that the cutout is designed to interrupt the generator when battery voltage is at whatever the voltage setting of the cutout is...correct? If the cutout interrupts the generator then doesn't the amp gauge read only whatever electrical load there is on the car? Engine, lights...etc? Wouldn't the amp gauge read negative in this case? Then, when the battery voltage gets low enough, wouldn't the cutout bring the generator back on line and the cycle starts all over again?? I'm wondering if my cutout is bad because the generator seems to be doing its job.
As a matter of future reference and off topic...I wasn't sure if I should revive this thread or start a new one on the same topic. What is forum policy on this? kirk
It seems to me that the cutout is designed to interrupt the generator when battery voltage is at whatever the voltage setting of the cutout is...correct? If the cutout interrupts the generator then doesn't the amp gauge read only whatever electrical load there is on the car? Engine, lights...etc? Wouldn't the amp gauge read negative in this case? Then, when the battery voltage gets low enough, wouldn't the cutout bring the generator back on line and the cycle starts all over again?? I'm wondering if my cutout is bad because the generator seems to be doing its job.
As a matter of future reference and off topic...I wasn't sure if I should revive this thread or start a new one on the same topic. What is forum policy on this? kirk
VeryTangled
Well-known member
I like to see things stay in one thread, makes it easier for me to stay on topic.
J Witt
Well-known member
As a child, on family trips from Savannah to Chattanoga we would see cars (ours too) on US 41 running with the lights on too avoid the dreaded boiling battery from overcharging.
This was in the late 40's to early 50's when my dad was stationed at Hunter AFB and most of the relatives lived in Chattanooga. We sometimes rode the dog when the family car wasn't reliable enough for the trip.
John
This was in the late 40's to early 50's when my dad was stationed at Hunter AFB and most of the relatives lived in Chattanooga. We sometimes rode the dog when the family car wasn't reliable enough for the trip.
John
Jeff/Illinois
Well-known member
karl, get Tom Wesenberg's Electronic Voltage Regulator and change it out for your third brush.
I swear by it, we have one in our '36 pickup and it works GREAT makes the gennie a lot more reliable, keeps the battery charged better w/o cooking out the electrolyte from overcharging.
I wouldn't be without it anymore. Tom is active on the Model A side you can PM him here just type in 'Tom Wesenberg'.
I swear by it, we have one in our '36 pickup and it works GREAT makes the gennie a lot more reliable, keeps the battery charged better w/o cooking out the electrolyte from overcharging.
I wouldn't be without it anymore. Tom is active on the Model A side you can PM him here just type in 'Tom Wesenberg'.
JSeery
Member Emeritus
I would get something fixed to correct this condition as quickly as possible, it is bound to damage the battery charging it at 9 volts. It will take a toll on the rest of the car as well, lights etc.
One way to go is an electronic cutout, but I would start by backing the charge rate on the generator down. There is no reason to be running it at this level. 10 amps (ever if it's a guess with the stock gauge) is way to much, should be right at 0 on the charge side slightly.