another charging question

[tab1324]

I'm still working on the charging system for my 82 XJ1100. Looking at the wiring diagram, I see that the field coil (the rotor bolted to the motor) should be able to be measured for resistance / continuity. I did this and came up with an open circuit. Could this be the problem? Is it supposed to be that way.

Basically, I measured resistance from the two "stripes" caused by the brushes on the rotor faceplate.

How do I remove the rotor if I want to replace it? Anyone know of one thats available?

Thanks,

Tom B.

[freebird01752]

Tab,

I see you are still chasing the charging problem. I am still having problems also. I can't beleive that I have 3 bad regulators. Everything I test point back to the regulator.

Steve

[tab1324]

resistance at field coil

Are you getting good resistance at field coil? (green and brown wires from alternator). Take the housing off and check resistance on the actual windings (stripes on the rotor). Maybe yours is fine but I've got 2 electrical engineers and 1 electrician saying that I should get a resistance or continuity measurement there. I'm not so they say that's whats bad.... We'll see.

So I take it your new regulator didn't work either? That's what sucks is when you figure it's something and you buy it and it still doesn't fix it... Plus you're out the money.

I'm with you...

Tom B.

[freebird01752]

Tab,

Yes I am getting resitance and continuity from both the stator and coils. Just not getting in increase in the voltage.

Yes it does suck that I out the money for the regulator.

Steve

[ratbyk]

Charging Problems

How are you measuring the alternator output?
Have you tried simply clipping a volt meter on the battery posts? Start the engine and take it to about 3000RPM and hold it there for 30 seconds or so while watching the volt meter on the battery. Just maybe your alternator really is charging and your method of checking is not indicating it.
Before starting note your present available battery voltage. If after staring it climbs then the alternator does have some output.
Possibly one of the 3 field windings is bad. The alt. is charging but not to it's full ability.
Just some thoughts and ideas. I'm no electrical guru but that is how I check if the alternator is functioning. Usually on my bike the volt meter hooked up like this will slowly climb to about 14 volts.
Ken/Sooke
78E Ratbyk
82 FT500 "lilRat"

[freebird01752]

Ken,

I have done that on my bike and the volts drop. With the switch off I read 12.79 volts. Start the bike and it drops to 12.10 at idel. Rev it to around 3000 and it stays around 12.10 to 12.20.

The part that is driving me mad is I can get a ohms reading one way but not the other. This makes no sense at all. My analigy is that if I can pour water in a tube from one end and the water comes out the other why can I pour the water the other way and have it come out from the other. Ohms should read in both direction right????
So far noone can tell why this is happening.


Steve

[Hobbit]

ohm readings

Steve,

An alternator uses diodes to provide DC voltage from an AC field. Diodes are like one way check valves that only allow current to flow in one direction. Your ohm meter uses a battery to send a very small current through the wire in order to calculate the resistance. This current (from the meter's battery) has polarity that can only flow through the diode in one direction. What you proved when you tested the wire in each direction is that the diode is working properly.