Stator and Rectifier

[bluecamel]

How would I know which mine is and is there something I should do other than just replacing the stator?

[bluecamel]

Well, I finally got to talk to the shop I really like around here and they've ordered me a stator. I'll let you guys know how it goes when I get it on there!

[mydlyfkryzis]

Actualy, there ar three type of systems.

1. Generator puts out DC volts. It has brushes and the rotor has a commutator on it. If you look at it carefully, it resembles a DC electric motor.
It has a rotating part (Rotor) and stationary part (Stator).

2. Alternator puts out AC volts. The alternator usually has brushes (some don't) and consists of a rotating magetic field (on the Rotor) whose strength is controlled by the regulator and a stationary coil (the stator) where the electric is generated.

3. Dynamo (Also called an alternator) puts out AC volts. It consists of a rotating magnetic field (the rotor). The rotor in this consist of permanent magnets. The magnetic field strength is not adjustable,. The stationary part (stator) where the electric is generated. The dynamo puts out current in direct proportion to it's RPM. To regulate this type, the regulator is a special type of diode called a Zener Diode. The zener diode acts as a voltage regulator by shorting the output above 14.6 volts to ground. It is a simple system, used by many bikes.

The drawback to a diode regulated system, is if you hook it up to a running car putting out more the 14.6 volts, the diode will ground it. since a car alternator can put out, in some cases, over a 100 amps, it overloads the diode and burns it out.

Other than that, the dynamo is a pretty reliable system.

[flynrider]

I have a question though. At the very start of that flow chart, it has me test the voltage across the battery terminals while revving the engine. When it was revved to 2500 rpm, it was considered good if it was above 13.5 V. Mine was sitting right at 13.5, but it was hard to keep the rpms right around 2500 rpm. At 5000 rpm, it was supposed to be less than 14.8 V, and mine was at 14.2 V. So, I could have reasonably assumed that the charging system was good just by that if I hadn't gone on to the later tests on the stator. I guess my question is, is it possible that my tach is inaccurate? It is 25 years old, so I wouldn't be surprised, though I don't know how those things go. I assume it was never intended to be super accurate and rather just a guide.

I'm suspicious. If you're able to get those kinds of voltages at the battery with the engine running, that means there is enough voltage in the system to charge the battery. If the voltage coming off the stator was really only .02V on each lead, then where is the current that you've measured at the battery coming from? If it's above the 12.4V you usually see at the battery with the engine off, then that means you're getting electricity from the charging system. The 13.5V-14.2V you measured at the battery would be considered a normal voltage for a normally operating charging system.

Generally, if you're not getting much out of the stator, then you won't see much above 12V at the battery with the engine running. Something is not adding up here.

[slimcolo]

mydlyfkryzis said generators have a rotating part (Rotor) and stationary part (Stator).

Although technically correct these names are seldom used on a generator system. The rotating part is usually called an armature and the stationary part fields. (like a dc motor)

This is again an area where there are different names for the same thing. Also the English refer to a generator as a dynamo. I have also seen Clymers and Haynes as well as factory manuals use different names for the same part.


What mydlyfkryzis refers to as dynamo Yamaha calls Flywheel Magneto other names for it include Magnetic Flux Generator (Triumph pre-unit) and Flux Magneto. There some bikes that use both diodes and a regulator.

Also some alternator systems have the rotor in side the stator like most cars (BMW) others have it outside (HD)[/quote]

[crazypj]

crazypj said

generator puts out max output for extended period and fries regulator.

and

New battery fitted which goes flat due to discharging through stator windings

Do you have a bike with two seperate charging systems? Generator (dynamo) and a stator (alternator)

I have one Harley putting out way too much (about 8 or 9V) and frying batteries, probably a sticking regulator (actually I know this) My solution replace battery, generator,coil,condenser, and lights with 12V and get rid of many other electrical problems at the same time.

Generator generates electricity, doesn't matter if its AC or DC
It is composed of two main parts
Stator, the stationary bit and rotor, the bit that rotates. (or field coil and armature for dynamo's, same thing, but different)
The rotor is a permanent magnet, unless its an electromagnet.
You have a Harley, which only recently joined the 20th century, pity we are now in the 21st (electrically speaking)
Early ones used two wire alternators, not sure about the dynamo ones, I suspect they were slightly better than Lucas but not much
The regulator is electronic which is much more efficient than mechanical type and also switches far faster ( around 400~600Htz) instead of around 60Htz or less for mechanical so points cant be sticking.
Switching isnt a problem with old bikes (points ignition) but itcan/could be a problem with modern set ups, regulator switching can trigger ignition or fuel injection at certain RPM (not good)
Just a bit of edjymucashun

[crazypj]

When I got to the part of measuring voltage coming out of the three yellow leads on the stator while running at 5k rpm, I was hardly getting 0.02 V from each and should have been getting close to 50 V. So, it seems my stator is definitely bad. Combine that with the fact that half of it looks sort of fried, I'm satisfied with the test. The tests I was able to do on the voltage regulator/rectifier seemed to pass, even though the dealer told me it was bad.

I have a question though. At the very start of that flow chart, it has me test the voltage across the battery terminals while revving the engine. When it was revved to 2500 rpm, it was considered good if it was above 13.5 V. Mine was sitting right at 13.5, but it was hard to keep the rpms right around 2500 rpm. At 5000 rpm, it was supposed to be less than 14.8 V, and mine was at 14.2 V. So, I could have reasonably assumed that the charging system was good just by that if I hadn't gone on to the later tests on the stator. I guess my question is, is it possible that my tach is inaccurate? It is 25 years old, so I wouldn't be surprised, though I don't know how those things go. I assume it was never intended to be super accurate and rather just a guide.

Anyhow, I'm going to now check into getting the stator coils rewound or just buying a new one. Then I'll run through the tests again once it's fixed.

Thanks!

Branton

You did check on AC Volts scale with probes between the pairs of yellows?
Did you do a grounding check? (any/all yellow to ground, one at a time) Should be NO continuity (in Ohms)
It may be just one set of winding burned (your low output)
It must be making more than 0.02V or it wouldnt go up to 14.2

[slimcolo]

crazypj wrote

You have a Harley, which only recently joined the 20th century, pity we are now in the 21st (electrically speaking)
Early ones used two wire alternators

And I have two bikes still running a 32E (3 brush) generator (last used by HD in 52) They now have alternator conversion kits available for these older bikes, but will get points taken off in a show and cost a fortune.
The two wire ones (alternator) are actually the later ones, the first generation alternator (70-75 BTs) were four wire.
And Harley joining the 20th century, News to me!
crazypj also wrote

I suspect they were slightly better than Lucas but not much

The tyre rubbing generator I had on my bicycle as a kid was much better than Lucas!
And to switching not being a problem with points yes BUT It can compound other electrical problems.

[bluecamel]

You did check on AC Volts scale with probes between the pairs of yellows?
Did you do a grounding check? (any/all yellow to ground, one at a time) Should be NO continuity (in Ohms)
It may be just one set of winding burned (your low output)
It must be making more than 0.02V or it wouldnt go up to 14.2

Well, I remember switching to AC Volts on one of the tests, but honestly can't remember if it was that one. I'm going back to my parent's place tonight, so I'll do the test again. If I remember right, I had it set to 200 on the VAC side, but I'll make absolutely sure.

I did do a continuity test, and got 0L on each yellow lead. I'll do that one again as well.

I didn't test the battery with the bike not running, but it should be 12V right?

Could the stator be intermittently working? Maybe I bumped something between the tests?

[crazypj]

Stator doesn't normally have intermittent problems. But, the leads from stator can get pinched under sprocket cover so moving them about can give weird readings. Check your getting good continuity by putting probes down between insulation and connector. 200VAC should be fine for no load test, I've seen 900's around 110v@5,000rpm
Battery voltage should be around 13VDC before starting tests and with engine running around 2,000rpm shouldn't drop
A cheap 60-0-60 (or 30-0-30) ammeter from Autozone/Pep-Boys, etc will give a good indication of charging current as long as its wired in correctly (in series) Quick way to do it is wire in instead of main fuse, not completely accurate but close enough. Will show discharge when you turn ignition on (and charge when its running above break even point-1800~2000rpm)
Good luck with it
PJ