TOPIC:

Do you have any old car headlights laying around?
My next step would be to do a load test on the stator. I use a 60 watt bulb and put it on each pair of yellow stator wires and run the bike. It should not take much revving to get the bulb bright.

But be careful, if the stator is working, you can burn out the bulb pretty easily.

Another option I might try is getting a $5, 3-phase rectifier and use that in place of the reg/rec. It won't regulate, but will let all of the stator energy pass to the bike. If that doesn't get the voltage up quickly, then the stator is suspect.

There are other options too, but those are probably the cheapest/simplest.

Obviously, you can get another stator too, but that's not exactly cheap unless you get lucky on ebay.

By the way, have you inspected the inside of the alternator housing to see if there any magnet issues or heat damage?

I have not removed the stator cover. I will do that this weekend.


ricksmotorsportelectrics.com/part/21-211/ODJLYXdLWjU1MEM=

Not sure why they show a single phase stator here.

I removed the alternator cover today.

The flywheel and stator both look pristine. I'm not sure how to measure the magnet's strength but a wrench stuck to each magnet.

No signs of heat damage to the stator. Put a headlight bulb on each pair of stator wires and the bulb light up. Tested each leg for VAC and one leg dropped down to near 0 VAC more than the other two. Pulled the light fuses and the battery voltage increased. I have some charging but it is weak.

At this point all I have to condemn the stator is one leg slightly weaker than the other two, and resistance measurements for all three legs that are over the FSM spec of 0.36-0.54 OHM.

I don't know if anyone mentioned it but what is the AC voltage per section, ahead of the R/R... with the engine running and the charging system under a load? As in, headlights on bright/passing, flasher going... etc.
Also, my DVMM has a diode test position that puts about 1.6-2.0vdc on the probes to fully bias the diodes "on" during a test and reversing biases the diodes "off".... yours?

Some/most 1980 Kz550's (and earlier) had 1-phase systems. All later years should be 3-phase.

Did it seem like you could get the bulb so bright it might burn out during the test?

I should have mentioned this earlier, but you can measure the voltage on the yellow pairs using the AC voltage setting on the meter. Then you could see the voltage vs RPM for each pair under load.


Measuring the AC voltage on the yellow wires while the entire charging system is connected usually shows very low voltages because the sine waves get clipped to square waves. AC meters are not very accurate when measuring square waves, and different meters will give different results since they estimate RMS in different ways. The voltages you can expect to see there, on a meter that is measuring a full-wave, rectified average will be around 7v to 12v, and interestingly, it will read higher when they are producing less power. This is a consequence of how meters work in combination with rectifying and shunting.

Here are screen shots of KZ550 charging system voltages for anyone interested, but it's not very helpful unless you are also using a scope:
home.comcast.net/~loudgpz/GPZweb/GPZAltn...rnatorWaveforms.html

loudhvx wrote: Did it seem like you could get the bulb so bright it might burn out during the test?

I did not rev up the engine because I didn't want glass everywhere. It was pretty bright.

loudhvx wrote: I should have mentioned this earlier, but you can measure the voltage on the yellow pairs using the AC voltage setting on the meter. Then you could see the voltage vs RPM for each pair under load.

All three yellow stator output wires measure 49 – 55 VAC @ 4000 rpm. The VAC readings jumped around but these are the peak readings I saw. A certain pair of yellow stator output wires read 49 VAC, slightly lower than the other two. This leg also dropped down to near 0 VAC more than the others.

Sounds like a bad connection. Check where the wires come from the windings, through the metal bracket then to the rubber grommet. I've had a bad connection there, soldered it and it was OK.
Steve

The_Proletariat wrote: I should have mentioned this earlier, but you can measure the voltage on the yellow pairs using the AC voltage setting on the meter. Then you could see the voltage vs RPM for each pair under load.

All three yellow stator output wires measure 49 – 55 VAC @ 4000 rpm. The VAC readings jumped around but these are the peak readings I saw. A certain pair of yellow stator output wires read 49 VAC, slightly lower than the other two. This leg also dropped down to near 0 VAC more than the others.[/quote]
I meant under load with the bulb connected. The meter's AC voltage reading on the bulb would indicate the power the bulb was receiving. Since it is not regulated in that condition, you can just make sure the AC voltage reading is around 14v and it should be safe. (For anyone reading this, it is not meant to imply 14v AC is always the same as 14v DC. But in this specific case, the voltages would deliver about the same power to the bulb.)

So maybe the new reg/rec is possibly bad as well, or as swest said, maybe there is a bad connection somewhere.

I replaced the stator.

I have not had to charge the battery for two weeks now. Voltage at 4000 rpm is not 14.5V. Instead, it slowly rises to mid-high 13V. Turn signals still do not work at idle however rev up the engine and they work fine.

How old is the battery?
Steve

He said he replaced the battery about a month ago.

It still sounds like there is a problem if you can't get to 14v. There are no extra electrical devices being powered, correct?

I'm afraid the testing required to get to the bottom of the problem is going to be more involved. For situations like this, I built an active load circuit. It varies the load to maintain 14v, while measuring the current. It gets wired directly to the stator, so the entire rest of the bike is out of the picture.

You can make a crude version by getting three 60 watt bulbs, and connecting each one to each pair of yellows. This creates a triangle (delta) shaped circuit. Then run the bike on the battery at idle. Measure the AC voltage on each bulb. Keep the meter connected to the highest voltage bulb (they should all be similar). Then see what RPM is required to get a 14v AC reading. That is the RPM at which the bike is producing about 180 watts.

If it never gets to 14v AC (which wouldn't be a surprise based on your existing problem), then you can use 3 50 watt (12v) bulbs instead. Actually, based on your current issues, maybe I would start with the three 50 watts.
Then you can find the RPM where you get about 150 watts.

I realize this is a lot of work and requires a lot of sourcing of parts and a bunch of time.

Since you already replaced the reg/rec, and the stator, the last thing left is rotor, (and there is always a possibility of a wiring issue too). So you can maybe cut to the chase and replace the rotor. But since you already went through the frustrating experience of replacing parts and not getting satisfactory results I thought I'd mention the more involved tests.

Sorry it's not resolved yet.

Is the rotor permanent magnet type?
Steve