regulator failure

Rob Kleinschmidt wrote:
> Just replaced my voltage regulator again after less than a year's
> service.
>
> This is an automotive type 3 wire regulator, energizing the alternator
> rotor through slip rings.
>
> Is this second failure pure coincidence and bad luck or could there
> be a problem such as a high resistance or bad diodes taking out
> the regulators ?
>
> Any insights or suggested diagnostics appreciated.

Get your jumper cables crossed?
 >> Stay informed about: regulator failure 

Rob Kleinschmidt <Rkleinsch1216128.DeleteThis@aol.com> wrote:

> Just replaced my voltage regulator again after less than a year's
> service.
>
> This is an automotive type 3 wire regulator, energizing the alternator
> rotor through slip rings.
>
> Is this second failure pure coincidence and bad luck or could there
> be a problem such as a high resistance or bad diodes taking out
> the regulators ?
>
> Any insights or suggested diagnostics appreciated.

What bike is it? Are we talking a separate regulator here or a combined
reg/rec?


--
K1100LT 750SS CB400F CD250 SL125
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
chateau dot murray at idnet dot com
 >> Stay informed about: regulator failure 

On Jan 2, 12:03�pm, Rob Kleinschmidt <Rkleinsch1216... RemoveThis @aol.com> wrote:

> This is an automotive type 3 wire regulator, energizing the alternator
> rotor through slip rings.

Is it actually a car voltage regulator, and not the OEM regulator, in
an attempt to save a bit of money?
>
> Is this second failure pure coincidence and bad luck or could there
> be a problem such as a high resistance or bad diodes taking out
> the regulators ?

http://www.xmission.com/~wendell/GS/node3.html
http://www.xmission.com/~wendell/GS/node27.html
http://www.xmission.com/~wendell/GS/node3.html

Is your GS wired like the diagram? I see three AC phase wires, a
ground wire, the red DC output to the battery, and a blue sensing wire
going to the regulator. The brown wire would be the field excitation
current and the black wire would be the excitation current return to
the voltage regulator.

Does your GS have a generator warning light in the speedo?

A pass transistor voltage regulator would simply apply 12 battery
volts to the transistor, and the current through the transistor would
be reduced by its internal resistance.

In the diagram, the transistor's gate gets about 14.5 volts from the
rectifier, and that shuts the transistor off until the voltage drops.

So the transistor is a switch that has to cycle continuously while the
engine is running and changing RPM.

The resistance of your alternator rotor might be low, or one of the
brushes may be shorting to the brush rigging, and that might be
blowing out the transistor in the regulator.
 >> Stay informed about: regulator failure 

On Jan 6, 12:49 am, totallydeadmail... RemoveThis @yahoo.co.uk (The Older
Gentleman) wrote:
> Rob Kleinschmidt <Rkleinsch1216... RemoveThis @aol.com> wrote:
> > Just replaced my voltage regulator again after less than a year's
> > service.
>
> > This is an automotive type 3 wire regulator, energizing the alternator
> > rotor through slip rings.
>
> > Is this second failure pure coincidence and bad luck or could there
> > be a problem such as a high resistance or bad diodes taking out
> > the regulators ?
>
> > Any insights or suggested diagnostics appreciated.
>
> What bike is it? Are we talking a separate regulator here or a combined
> reg/rec?

R100GS with separate diode board.
 >> Stay informed about: regulator failure 

Rob Kleinschmidt <Rkleinsch1216128.TakeThisOut@aol.com> wrote:

> On Jan 6, 12:49 am, totallydeadmail....TakeThisOut@yahoo.co.uk (The Older
> Gentleman) wrote:
> > Rob Kleinschmidt <Rkleinsch1216....TakeThisOut@aol.com> wrote:
> > > Just replaced my voltage regulator again after less than a year's
> > > service.
> >
> > > This is an automotive type 3 wire regulator, energizing the alternator
> > > rotor through slip rings.
> >
> > > Is this second failure pure coincidence and bad luck or could there
> > > be a problem such as a high resistance or bad diodes taking out
> > > the regulators ?
> >
> > > Any insights or suggested diagnostics appreciated.
> >
> > What bike is it? Are we talking a separate regulator here or a combined
> > reg/rec?
>
> R100GS with separate diode board.

Oh blimey.

It's usually the diode board on ShiteldBoxers that gives trouble.
Funnily enough, I was looking at an R100RS recently with just that
problem.

And IIRC, a diode board and associated bits is something like £300
($600). Can't remember if that's with the regulator or not.

My money would be on the diode board being faulty.


--
K1100LT 750SS CB400F CD250 SL125
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
chateau dot murray at idnet dot com
 >> Stay informed about: regulator failure 

On Jan 6, 11:23 pm, totallydeadmail....RemoveThis@yahoo.co.uk (The Older
Gentleman) wrote:
> Rob Kleinschmidt <Rkleinsch1216....RemoveThis@aol.com> wrote:
> > On Jan 6, 12:49 am, totallydeadmail....RemoveThis@yahoo.co.uk (The Older
> > Gentleman) wrote:
> > > Rob Kleinschmidt <Rkleinsch1216....RemoveThis@aol.com> wrote:
> > > > Just replaced my voltage regulator again after less than a year's
> > > > service.
>
> > > > This is an automotive type 3 wire regulator, energizing the alternator
> > > > rotor through slip rings.
>
> > > > Is this second failure pure coincidence and bad luck or could there
> > > > be a problem such as a high resistance or bad diodes taking out
> > > > the regulators ?
>
> > > > Any insights or suggested diagnostics appreciated.
>
> > > What bike is it? Are we talking a separate regulator here or a combined
> > > reg/rec?
>
> > R100GS with separate diode board.
>
> Oh blimey.
>
> It's usually the diode board on ShiteldBoxers that gives trouble.
> Funnily enough, I was looking at an R100RS recently with just that
> problem.
>
> And IIRC, a diode board and associated bits is something like £300
> ($600). Can't remember if that's with the regulator or not.
>
> My money would be on the diode board being faulty.

I've heard that from others but can't quite figure out
how that could cause the symptoms I'v seeing.

Measured with an ohmmeter, the diode board looks
OK, at least the three large ones for rectifying the
AC output. I've got a spare I can look at and compare.

Motorrad Elektrik in the U.S. sells a well thought of
aftermarket diode board for $90. The BMW price you
quote is ridiculous and probably accurate.

http://www.motoelekt.com/charging.htm
 >> Stay informed about: regulator failure 

On Jan 7, 10:00�am, Rob Kleinschmidt <Rkleinsch1216... RemoveThis @aol.com> wrote:
> On Jan 6, 11:23 pm, totallydeadmail... RemoveThis @yahoo.co.uk (The Older
> > My money would be on the diode board being faulty.
>
> I've heard that from others but can't quite figure out
> how that could cause the symptoms I'v seeing.

The usual 3-phase full-wave rectifier bridge has SIX diodes and the
three AC input phases are hooked up between the anodes and cathodes
of THREE pairs of diodes.

http://www.electrosport.com/Images/instr.diode.test1.pdf

Voltage on each phase rises in rotation, A phase, B phase, and C
phase,
and power from each phase has to return to a different phase in that
rotation.

All SIX diodes get used, as the current changes polarity at varying
frequency.

If ONE diode is OPEN, AC power from one phase obviously cannot return
to the
other phase for half a cycle, and you lose half of the alternator's
output power for half a cycle.

If ONE diode is SHORTED to ground, you also lose half the alternator's
output.

I disagree with Electrosport's statement that you can't test a diode
with an analog meter. The main thring that happens with the analog
meter is that it puts so much current through the diode, you get a
reverse polarity reading, IOW, the diode reads continuity AGAINST the
arrow, instead of with the arrow.

No matter. If you put your positive ohmmeter lead on any of the yellow
AC inputs, and the negative lead on the rectifier bridge's black
output wire, and you don't get a reading on the Rx1 scale, switch the
leads and check again, because you may just be over-biasing the diode
with the analog meter.

If you get a reading from any yellow wire to the black wire, you
should get the SAME reading between each of the other two yellow wires
and the black wire.

It might be around 15 ohms, but the exact reading is dependant on the
internal resistance of your analog meter. That tests THREE of the SIX
diodes.

Then put the negative ohmmeter lead on the red wire and run your
continuity check to each of the three AC input leads. Again, you
should get the SAME reading on each of the three phases. If they they
all read the same, those THREE diodes are OK.

> Measured with an ohmmeter, the diode board looks
> OK, at least the three large ones for rectifying the
> AC output. I've got a spare I can look at and compare.

If you only have THREE power diodes, you have a HALF-WAVE rectifier
bridge. I cannot imagine any sane electrical engineer designing such a
device that ignores half the power of the alternator.

Electrosport makes a modern rectifier unit housed in a heat sink. The
price is $129.

http://www.electrosport.com/Images/fitting.esr450.pdf
 >> Stay informed about: regulator failure 

On Jan 2, 12:03 pm, Rob Kleinschmidt <Rkleinsch1216... DeleteThis @aol.com> wrote:
> Just replaced my voltage regulator again after less than a year's
> service.
>
> This is an automotive type 3 wire regulator, energizing the alternator
> rotor through slip rings.
>
> Is this second failure pure coincidence and bad luck or could there
> be a problem such as a high resistance or bad diodes taking out
> the regulators ?
>
> Any insights or suggested diagnostics appreciated.

I uncovered a second problem in the starter. One bad spot
on the starter seems to have been shorted out and creating
a serious path to ground when the starter was positioned
just right.

Battery would drop below 9 volts without cranking while
at some other times, it would crank just fine. The starter
was just over a year old and the shop I bought it from
replaced it without question when I reported the symptoms.

I'm not really clear what the exact failure was or how a
bad short would take out a 3 wire regulator, but having
replaced both of them everything seems to be working
fine again.

The tests I should have made immediately were to
charge and test the battery, then monitor battery voltage
while attempting to crank the bike over. The voltage
drop was an obvious clue that I should have caught
earlier. Instead, I let the bad starter trick me into thinking
there was a bad connection causing it to not work.

Thanks to all for the suggestions and advice.
 >> Stay informed about: regulator failure