CB650 charging issue

I helped build Apollo 13, and all the rest of the manned Apollo
capsules, back in 1968 and 1969.

You wouldn't believe how little the rest of the spacecraft
electricians knew about electrical theory and what the meter readings
indicated.

For instance, I had to straighten out the lead man of the bunch that
was resistance testing the valve heaters on the service module engine.
They kept getting the wrong readings and I had to instruct the lead
man (a former Air Force tech sergeant) about the formula for Ohm's Law
in parallel circuits.

Once I had him believing me, we hooked up the valve heaters correctly.

 

You should be able to read from the black wire to the white wire, in
the disconnected plug on the wire harness that goes to the brushes,
and get about 4 to 6 ohms.

The stator has three phases and is wye-wound with an un-grounded
neutral, so any reading to the engine or chassis indicate a short to
ground.

Any of the three coils in the stator would produce about 60 volts,
open circuit, at some unknown RPM, but since they are all connected
together at the neutral point, each coil gets assistance from the
following coil in sequence and produce 1.73 times the normal 60 volts.

1.73 is the square root of 3, there are three coils. If the stator was
star-wound, with five coils tied together at the center, they would
produce 2.24 times the nominal voltage, 2.24 being the square root of
five...

Ain't it wonderful what my Uncle Sammy taught me in tech school?

The fact that you get a reading from any yellow wire to any other
yellow wire in the stator, and no reading to ground on the highest
resistance scale available indicates a good stator

You have a bad connection in the field circuit at some point, it may
be internal inn the rotor, it may be a stuck brush, or a corroded pin
in the wire harness connector.

Maybe the regulator isn't getting battery voltage at all?

There are six power diodes inside the rectifier regulator and the
three stator leads are connected between the anode and cathode of
pairs of diodes. So you can read the resitance of three diodes with
the ohmmeter hooked up postive to negative, then you reverse polarity
and read the resitance of the other three diodes. This arrangement is
called a "three phase, full wave rectifier".

You should get the same resistance reading from each yellow phase wire
through three diodes, then reverse the leads and read the same
resistance through the other three diodes.

If you get no reading through any one diode, you lose half of the
power of that phase for half a cycle. If you get no reading through
two diodes, chances are you've lost half the power of the alternator.

Brush wear depends on how the motorcycle was ridden. I wore out a set
of brushes in my GSXR in 10,000 miles, but never wore out the brushes
in either of my GT750's in 90,000 miles.

Confucious say, "Man with ohmmeter make fool out of self when he
assume that
reading on meter mean anything."

I have spent hours crawling around inside of airplanes with an
ohmemeter in one hand, a wiring diagram in the other, and an
assumption that the test current from the meter was going through the
expected wires and components.

 

I think it's all good stuff, having a 2nd-level understanding makes 1st
level diagnosis a lot easier for me.

 

I helped build Apollo 13, and all the rest of the manned Apollo
capsules, back in 1968 and 1969.

You wouldn't believe how little the rest of the spacecraft
electricians knew about electrical theory and what the meter readings
indicated.

For instance, I had to straighten out the lead man of the bunch that
was resistance testing the valve heaters on the service module engine.
They kept getting the wrong readings and I had to instruct the lead
man (a former Air Force tech sergeant) about the formula for Ohm's Law
in parallel circuits.

Once I had him believing me, we hooked up the valve heaters correctly.


If I was on the crew of Apollo 13, while Tom Hanks was on the tonight Show,
pre-launch, I would have already considered everything that could fail and
designed those duct tape contraptions in my head, and made sure I brought my
Leatherman along, having rebuilt a carburator in a stepvan using a Swiss
Army Knife on the road once.

I have a manual on how to use Multi-Testers that has good instructions for
checking continuity on power cords for your toaster, but says nothing about
how/when to use the seven different scales on the ohmmeter. It does say that
if resistance is too large to measure it will read "1" for infinity-- but
since it always reads "1" for infinity, how do I know if its the default
infinity, or the reading across the component, or a lousy connection? That's
stuff for Uncle Sam to ponder. On Appollo 13 I'd have duct taped that meter
to Tom Hanks's air supply tube along with its manual.

I have to wait for delivery of an oil filter bolt I ordered before I can run
the bike for further probing of the charging system -- should take a couple
days. In the meantime I will try to think through what you said about my
results so far. Isn't there some kind of pill you can take for this problem?

pflu

 

And look what happened to that.......

 

If he trys to convince me to change my fuel system to liquid oxygen or
something I will begin to worry he's trying to send my Honda into orbit.
pflu

 

The Apollo program ran *unbelievably* smoothly, with only three in-
capsule fatalities and one aborted mission.

The handling of the abort and return to Earth was Gene Kranz' and the
Apollo team's finest effort.

The explosion of the LOX tank was blamed on short-circuited internal
heaters, but I recall an incident which happened to one of the service
modules (I'm not sure which production serial number service module)
when technicians tried to remove the wedge-shaped cryogenic shelf
containing the hydrogen and oxygen tanks.

Somebody failed to remove one 1/4" high strength bolt, and when the
crane operator tried to lift the shelf, he was picking up the whole
13,000 pound module by that one bolt, which snapped.

The cryogenic shelf flew out of the module and went swinging into the
catwalk guard rail and back into the service module bay before it
stopped.

I have always wondered if that was Apollo 13, but the modules were
stacked in whichever test stand was available at any given time.

Production serial number 101 was Apollo 7, it orbited the Earth with
Wally Schirra as spacecraft commander.

PSN 102 was scrapped because it had so many repairs and reworks it
would have been like flying an old junker into space.

PSN 103 was Apollo 8, commanded by Frank Borman. It went around the
Moon during Christmas of 1968.

PSN 104 was Apollo 9, which practiced docking and undocking in Earth
orbit.

PSN 105 was an acoustic vibration test vehicle which is on public
display.

PSN 106 was Apollo 10, which practiced docking and undocking in orbit
around the Moon.

PSN 107 was Apollo 11, the first Moon landing.

PSN 108 was Apollo 12, the second landing.

PSN 109 was Apollo 13...

And on, and on, the spacecraft flew in order of production serial
number.

 

And on, and on, the spacecraft flew in order of production serial
number



I remember watching the Columbia explosion on TV, then a bit later on the
car radio it was offhandedly mentioned that one of the possible causes was a
rubber "O" ring failure because it got brittle in the cold. Having just
re-built a VW engine in which the valve stem tubes had brittle "o" rings I
had to replace, the notion blew me away -- I remember thinking about how
they needed to add a few yard-tree mechanics to support their engineers. It
would have been like me starting my old VW up in winter and immediately
jumping on the expressway and gunning it full throttle -- what could
possibly go wrong? My uncle, who was a yard-tree artist would have foreseen
that problem at the time it was first discussed.

I think sometimes training can put blinders on common sense -- the fact
that a committee of engineers can approve something disastrous shows they
all come from the same school of thinking. Then sometimes things happen and
you just cannot believe they ignored something basic -- like I've heard they
are realizing that Big Brown pulled up during the Belmont Stakes, losing the
Triple Crown, because of a loose horseshoe. They showed a video of an
obvious shoe barely hanging on all crooked during the race. So dumb it is
unbelievable, but it happens.

pflu

 

And when you replace the brushes it is a good idea to clean that film
off - which I didn't do the last time I replaced the brushes, not realizing
the significance.. Which is why the slip ring cleaning worked for me.

Ted

 

Thanks. After reading this guy's post I found your original thread (where
you mentioned the brushes inability to dig into the crud). So I went back
and found there was still a layer of junk on there. After I cleaned it down
to bare copper I was hoping for the best but, other than giving me a more
stabile meter reading between the rings, it did not help with the charging.

pflu

 

You can't troubleshoot this system without the engine running.

Start the engine. Take a meter and read the voltage at the wires going to
the rotor and the voltage at the wires coming from the stator. The wires
coming from the stator are the yellow ones. Make sure when you measure
the yellow wires your on the AC selection of the meter, when you measure
the wires going to the rotor you are on the DC selection.

If you have power going to the rotor, and no power coming out of
the stator, then with the engine running, use the "deflecting feeler guage"
test mentioned in my original thread that was suggested by someone
else. If you put a feeler guage a couple mm from the rotor case
and feel no magnetic attraction, yet there is 10-12 volts going into the
rotor, then the rotor is bad. If you feel a magnetic attraction but
there's no power coming out any of the stator wires, then the
stator is bad. If there's no power going into the rotor then the
voltage regulator is bad. ANY bad connection in the charging
circuit will invalidate any of those readings.

Was the bike running when parked?

Ted