Topic: Glass? Behind generator cover?

[odioanonimo]

So I have the 82 cb650sc engine on the stand so it can get a little lovin'.  One of the various issues it was having was the charging system.  So I tested resistance across the yellow ac power wires coming out of the stator.  All were between 2.5 and 4.2 ohms, spec is... Something like .4? I wanna say? So I pulled the stator.  And inside it's case I found a bunch of what appears to be glass? But I have no idea where it could have come from?

[754]

Like little tiny round bits sorta like sand ?

[Don R]

 Epoxy from the windings?

[odioanonimo]

not sandy... just like... shards?

[dave500]

is it some coating of the windings?they use a hard setting sort of shellac stuff.

[strynboen]

if the stator have be re-build..the spilled or ekstra lauqer can peell off the metal ,,and fall aut..normaly ve klean it ,,before it cool dovn..and it still are soft..but some let it all be on the metal..and themn rust vill go under.. and press it free

[bryanj]

If you can find bits of Budwieser lable i would be worried about the state of the po on previous rebuild!

[odioanonimo]

I looked over that stator again and again then what strynboen said got me thinking .. and I looked in the casing and found the laquer coming off the rotor.  Thanks guys.

[TwoTired]

Far more likely the rotor fail than the stator without some physical trauma.
When the rotor windings begin to short between them, more current is drawn and the rotor heats up to melt even more of the wire insulation material.  Eventually the rotor draws enough current to fail the power driver in the regulator.

What does your meter show if you simply join the probe tips?
What is the confidence on the accuracy of your measurement?

Cheers,

[odioanonimo]

that, sir... is an excellent question.

i never thought to question my meter until you put it to me! now i feel like i cant trust the bastard

so i tested them against a couple of 100ohm resistors.

meter read between 99.6 and 100 for five resistors.  so i think its at least pretty close?

[odioanonimo]

oh and i think there was some physical trauma.  my brother dropped her.  i tested the rotor a little bit ago and it read about 4.5 ohm between the rings

[TwoTired]

I've had meters go wonky on me and lead me down an errant truobleshooting path.  Wastes time and money in parts trying to fix a circuit that the meter said was bad.  Taught me a lesson that regular test equipment calibration is a valid routine, similar to scheduled tune-ups.  It would be better if you measured a known 10 ohm resistor, as that is closer to the resistance you are presently measuring. And some meters can error depending the measurement range selected.  It's like a transmission where you lose of have a single gear be bad, but the rest of the gears work fine.  Similarly, even an auto ranging meter can give improper readings on certain measurement values.  It is rare these days, though.  But, I find it extremely important that my measurement devices don't lie to me.  I built a "decade box" to check my meters when I get unexpected readings, and gain confidence they are real.

The rings attach to the rotor, not the stator.  But, you knew that, right?
4.5 ohms for the rotor is acceptable, if not a bit on the low side.
You are confident your 3 stator wires are also reading 4.2 ohms between them?
You ARE subtracting the meter lead resitance from that measurement, right?
The unit measurements are actually lenghts of wires, and you are adding the meter's wires to that measurement. The test aparatus resistance should not be added to the unit under test.

Cheers,

The closer to zero ohms

[odioanonimo]

All very good points.  Yeah the rings on the rotor measure four and a half.  The yellow wires coming from the stator read... #$%*... Whatever I said before two point something up to four point something.  The leads connected to each other just reads "ol" so I figured there was nothing to subtract.   I suppose I could tap into the line somewhere Midway with some piercing leads to make sure there's not somethink wonky with the connectors... But this isn't even close.

Also... You've got me doubting my meter again.  I'll test it against some smaller resistors.  Maybe a 1 and a 10

[TwoTired]

On a resistance scale, touching the probe tips better show something near zero ohms, cause that is what a direct short comes pretty close to being.  OL stands for over load, or out of measurement range, which would be far closer to infinity resistance, or open circuit.

Cheers,