Re: Suggestions on a Honda charging system


"ian field" <dai.ode@xxxxxxxxxxxx> wrote in message
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"Ted Mittelstaedt" <tedm@xxxxxxxxxxxxxxxx> wrote in message
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"Rob Kleinschmidt" <Rkleinsch1216128@xxxxxxx> wrote in message

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On Jun 9, 5:09 pm, "Ted Mittelstaedt" <t...@xxxxxxxxxxxxxxxx> wrote:
"Rob Kleinschmidt" <Rkleinsch1216...@xxxxxxx> wrote in message


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On Jun 9, 12:17 am, "Ted Mittelstaedt" <t...@xxxxxxxxxxxxxxxx>
wrote:

I've replaced the regulator/rectifier with no change in
behavior. On both units, the diodes passed the ohmmeter
check.
Both rotor and stator pass the resistance checks in the
FSM. There are no shorts to ground on either one. This
is true whether the bike is cold or warm. I've cleaned all
the electrical contacts. The rotor brushes both have plenty
of material left on them. Power output of the alternator
does not change whether the bike is warm or cold.

I fixed a drop in charging by replacing a set of brushes
even though the old ones had only about 50% wear.
Not sure if the brush was beginning to hang up or if
it was just the increased pressure but at $9 for new
ones, it was well worth swapping them as an experiment.

Even if they're not obviously bad, replace the brushes if
they're near 50% gone.

They aren't. I just replaced them last year, and the old ones
were indeed worn out. But I will check the springs, perhaps
the ones I put in had weaker springs. I did save the old
brushes just for use in identifying new ones.

Might not hurt to swap in a new
regulator as well.

Already tried.

You could check this by jumpering
out the old one to constantly energize the rotor. On mine,
there's a standard 3 wire automotive regulator and it's
a simple jumper across two connections.

My guess is that either the rotor or stator has some windings
that have broken down. Unfortunately, the FSM has no
listing of what voltage is supposed to be on the field, and
stator, at a given RPM.

There should be a known resistance value for both
the rotor and stator that you could check. Resistance
values should be available on an owners list.

There is. But, DC resistance values are usually bull*** in this
application. Your dealing with an AC system.

A perfect rotor with superconducting wire .....

Fer Gawds sake !!! There's a resistance value both for the
rotor and for resistance between phases in the stator.
For my bike, these are approximately 3.4-3.7 ohms and
6.2-7.5 ohms respectively. This really ain't rocket science.
It's a part spec. Parts outside that spec are suspect.


Yes, I am aware of that. As I said in the original post,

"...Both rotor and stator pass the resistance checks in the
FSM..."

FSM = Factory Service Manual.

The Honda factory service manual gives the DC resistance.

I should have really clarified what I was meaning, though,
when I said that these checks are usually bull***.

The reason they are misleading, is that IF they
pass, that is NO guarentee that the part is good. Windings
fail in weird ways. I've seen transformers where they
overheated and in one part of the winding the coils
melted off their insulation and shorted - thus dropping
the resistance - and in other parts they merely melted
and didn't short, but instead burned through, yet enough
wire-to-wire contact remained that there was some
conductivity left - thus raising the resistance. As a result
the static resistance was similar as before, it is just
that the transformer doesen't work. An alternator is
the same deal, it's just windings.

Its certainly true that a single shorted turn would make no visible
difference to the DC resistance - but a big difference to the alternating
current output of the winding.

For testing motor armatures, there is a test jig known as a "growler", its
basically just a shaped laminated core with a mains coil wound on it, the
poles of the armature are offered up to the poles of the growler which
buzzes in a different way when its in contact with a pole that has shorted
turns. Not much use with an alternator stator with inside pole pieces but
the basic concept might inspire something.

If you can get hold of a variac (rotary variable auto-transformer to give
its full technical name) feed this to a normal step down transformer of at
least 12V secondary, and an AC ammeter. With this you can set a convenient
current to measure through one arm of the 3-phase winding and compare any
one with the other two. This trick is no good for the field winding
though,
the excitation voltage is DC, so it doesn't have a laminated core - the
solid core behaves like a shorted turn to AC.



There is aso another way to do it. Each stator leg
is a coil. So what you do is you take an AC adapter (wall wart) with
6 volt, 60 cycle AC output, feed that to the coil in series with a
potentiometer.
Then take 2 DMMs and connect one across the pot, the other across
the coil. Adjust the pot until the voltages across the pot and across
the coil are the same. Disconnect the pot and measure it's DC resistance.
You now have the inductance of the stator leg.

Since Honda didn't see fit to publish the inductance of these parts,
you would have to take a known good stator for your
model, measure it's inductance, then measure the part to be tested.

The rotor can be measured a different way. Energize the rotor with
12 volts. hold it over a steel washer, bringing it closer and closer to
the washer. Measure the distance from the rotor to whatever the
washer was sitting on at the point the rotor sucks up the washer.
It's a crude way of measuring the strength of a magnetic field.

Ted


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