Generator light, want to verify what an 'old timer' told me

[JohnnyBadBrains]

First off, I read everything I could find on this Forum and did not find this issue covered, because I don't want to be that pain in the butt guy who wants everyone else to do the thinking for me, because that's no fun. Here's the deal: I bought a rebuilt generator (in an original HD case even), from a reputible old school HD shop in Phoenix AZ that has been at it for over 35 years. I am on 12V conversion, Bosch Volt regulator that I flashed or polorized during generator installation. After riding her for about 500 to 700 miles at times quite fast (70 -85 MPH) for short bursts, I realise that my gen light on dash starts to glow now when I am revving and putting a load on the engine. after backing off throttle, light goes off (This is opposite of what I would expect, you know, glowing light at lower speed and idle etc..) This happens both when headlight (hi or low beam) and passing lights are on or off. I thought it was a vibration or shorting problem, tracked wires from end to end, all connections, looked to make sure no bolts were too long, grounding out on something with no luck. I've put another 1500 or so miles on it, a nice mix of streets and freeways out here in Phoenix, and it still does this. I keep a trickle charge, or battery tender on battery and the battery is not losing any of its juice.

Now, here's what I'd like to ask you all to verify: A fella I met was selling off some Panhead / Flathead parts after being at it for more than forty years and currently has 18 pans/shovels and flatties told me it's because I took her over 70MPH and the armerature vibrated out of field, that these pans were never made for such speed out of the factory and if I add an additional collar, or sleeve arounf the armature end on left foot side of bike, I will never have this problem again as it will keep the armature in field and let me roll as fast as I am comfortable.

I've been and wnat to continue to ride this and the '38UL daily but don;t wanna burn through a generator or two a year, so can any one give me your opinion or verify that you;ve heard of this fix before?

Sorry so long, just wanted to give all relevant info so you could think on it without having to ask other questions, but if you need to, heck, please do.

As always, thanks in advance for any info you all provide

JohnnyBadBrains

[john HD]

never heard of anything like that.

i'd try another or a different type of regulator.

your battery is fully charged?

john

[awander]

It definitely sounds like that "old timer" doesn;t know what he's talking about.
Being old gives you the opportunity for wisdom; but it doesn;t guarantee it....

[fourthgear]

First off, I read everything I could find on this Forum and did not find this issue covered, because I don't want to be that pain in the butt guy who wants everyone else to do the thinking for me, because that's no fun. Here's the deal: I bought a rebuilt generator (in an original HD case even), from a reputible old school HD shop in Phoenix AZ that has been at it for over 35 years. I am on 12V conversion, Bosch Volt regulator that I flashed or polorized during generator installation. After riding her for about 500 to 700 miles at times quite fast (70 -85 MPH) for short bursts, I realise that my gen light on dash starts to glow now when I am revving and putting a load on the engine. after backing off throttle, light goes off (This is opposite of what I would expect, you know, glowing light at lower speed and idle etc..) This happens both when headlight (hi or low beam) and passing lights are on or off. I thought it was a vibration or shorting problem, tracked wires from end to end, all connections, looked to make sure no bolts were too long, grounding out on something with no luck. I've put another 1500 or so miles on it, a nice mix of streets and freeways out here in Phoenix, and it still does this. I keep a trickle charge, or battery tender on battery and the battery is not losing any of its juice.

Now, here's what I'd like to ask you all to verify: A fella I met was selling off some Panhead / Flathead parts after being at it for more than forty years and currently has 18 pans/shovels and flatties told me it's because I took her over 70MPH and the armerature vibrated out of field, that these pans were never made for such speed out of the factory and if I add an additional collar, or sleeve arounf the armature end on left foot side of bike, I will never have this problem again as it will keep the armature in field and let me roll as fast as I am comfortable.

I've been and wnat to continue to ride this and the '38UL daily but don;t wanna burn through a generator or two a year, so can any one give me your opinion or verify that you;ve heard of this fix before?

Sorry so long, just wanted to give all relevant info so you could think on it without having to ask other questions, but if you need to, heck, please do.

As always, thanks in advance for any info you all provide

JohnnyBadBrains

Well I'm screwed with both my Pan's than !

[mbskeam]

flying short....,
if ya call cycle electric they may be able to shed some light...

[FlatHeadSix]

BadBrains
Your old timer was probably refering to the original 3-brush 32E generator. The old 3-brush systems lose efficiency at high rpm, it is the way they are designed and there is nothing you can do about it except slowing down to 1940 highway speeds. Your old time advisor guy is partially correct about the field and the armature, at high rpm the 3rd brush is not able to make sufficient contact with the commutator on the armature to energize the field coils. The only fix is to remove the 3rd brush and convert the generator to a 2-brush unit and add a voltage regulator.

But, that can't be your problem because you are already running a 2-brush 12 volt (I assume) and a regulator. It is hard to diagnose from here but I would suspect the rebuilt generator. Swap the regulator first as John said (its easier), if that doesn't get it then take a look at the rebuild genny.

There is no reason you can't run as fast as the flattie will safely go with that old springer front end.

keep us posted, let us know what it turns out to be.

mike

[Cotten]

I'm really not well versed on e-leck-trawnics...

But I think the only way you can get a 2-brush armature "out of field' is to remove the two long bolts that go through the generator so you can pull the end off.

....Cotten

[FlatHeadSix]

actually Cotten, the armature goes in (and out) of one of the two fields in the generator twice every revolution, that's how they work

mike

[partshunt]

Cotton:- Sounds to me like the term "in and out of field" is a bit confusing to us. What they mean by that is, that the armature ROTATES passing thru one field then half way around to and thru the other Magnetic field. Not an end travel in and out of the fields like it may sound. Its like you say, to pull the armature out of field horizontally, you would have to dismantle it. my pennys worth ..lol...Joe

[awander]

Well, I would quibble a bit with that terminology.

The armature doesn;t go "out of the field", the field is something that exists in the area between(and also outside of, to a lesser extent) the 2 field COILS, and that is where the armature lives, so while different armature coils DO pass "through" the field, no part of the armature ever goes "out of the field".

I do see why some might call it that, but technically it is not even close to being correct.

[awander]

While it may be true that the old-timer was referring to the 3-brush generators characteristic of dropping off in charge level at higher RPM, the phenomenon has nothing to do with "vibration".

I also don't believe that it has to do with how good the contact of the 3rd brush is on the commutator. I think it is strictly a case of the electrical characteristics of the 3-brush system.

I am willing to be enlightened, though...

[FlatHeadSix]

Andy,
The 3rd brush is actually the "ground" which completes the circuit in the field coil and creates the magnetic field that the armature "cuts" or passes through to generate the current. It works best when there is a large potential, or difference between the battery voltage supplied to one side of the field coil and the output of the generator. So, when the generator speeds up and starts putting out lotsa juice the potential at the 3rd brush decreases and begins to approach the same voltage that is on the other side of the field coil, this, in turn, decreases the strength of the magnetic field and lowers the output of the generator. It works kind of like a dimmer rheostat. The 32Es where self limiting and internally regulated by this method, it kept you from boiling the battery dry on long fast runs and, more importantly, it kept the generator from self destructing. It was a pretty good system for its day. If you are familiar with the old automotive idiot lights which indicate charge those work on exactly the same principle, if the voltage is the same on both sides of the light it goes out.

I didn't want to get into it this deep in my first post but you asked for it and there it is, too late now....

mike

[Panacea]

Interesting stuff Mike. You have a way of enlightening us, (no pun intended...)

[NightShift]

Andy,
The 3rd brush is actually the "ground" which completes the circuit in the field coil and creates the magnetic field that the armature "cuts" or passes through to generate the current. It works best when there is a large potential, or difference between the battery voltage supplied to one side of the field coil and the output of the generator. So, when the generator speeds up and starts putting out lotsa juice the potential at the 3rd brush decreases and begins to approach the same voltage that is on the other side of the field coil, this, in turn, decreases the strength of the magnetic field and lowers the output of the generator. It works kind of like a dimmer rheostat. The 32Es where self limiting and internally regulated by this method, it kept you from boiling the battery dry on long fast runs and, more importantly, it kept the generator from self destructing. It was a pretty good system for its day. If you are familiar with the old automotive idiot lights which indicate charge those work on exactly the same principle, if the voltage is the same on both sides of the light it goes out.

I didn't want to get into it this deep in my first post but you asked for it and there it is, too late now....

mike

I gotta print that out!

Thanks,

[mbskeam]

idiot

whats this mean, please explane to me...LOL

good post, me likeee