Charging Question

[Squidley]

I have been searching through some of the old threads about stators and charging. I just installed a new stator in my '86 that was purchased from Ricks Motorsports. This was a new higher output they call a Hot Shot. I installed it quite uneventfully and got all the wiring hooked up with new connectors. Bike fired right up and sounded great, but wasn't charging. Shut her down and then unplugged the 3 direct AC wires from the stator and tested my AC volts across the 3 wires, which were 25 volts AC. I thought that seemed kind of high, so I looked on the site to see what others had to say. I didn't get a definitive feel, so the question I have is 25 VAC too much for this stator to be pushing out.

I'm kind of leaning towards the R/R being the culprit, even though it is brand new and a match to the stator. I just wanted to get a feel from y'all about the 25 VAC I'm getting from the stator.

[playboy]

I think any AC voltage would be high no matter was your meter on AC or DC ?

[Condor]

Get ahold of Dano... He knows everything there is to know about our stators and rectifiers....

[BuddyRich]

Ac would be higher as the rectifiers change it from ac to dc. Half of 25 would be 12.5. So it may not be high enough. But it was 40 years ago I was learning about rectifiers so I could be,,, uh,,, forgetful...

[MiCarl]

Brad,

 

25 isn't high. I'm guessing that is at idle........

 

Remember, in your test you have no load on it so the voltage goes way high. When you connect it to the motorcycle current begins to flow and the voltage will drop a lot. Motorcycles that have an unloaded AC output spec. are usually above 60V at 4-5K rpm.

 

The test you're doing is really only of use to find if you have a short. It's a little better than using an ohmmeter because at voltage you can have a "leak" through bad insulation. If there is a "leak" the voltage will be below spec. The voltage will also be low if there is a problem with the magnet in the rotor.

 

There is really no way to make the voltage too high without putting extra windings on the armature or a stronger magnet in the rotor. Because of the limited space the wire would be so thin it'd burn up as soon as it had a load on it.

 

I suspect that the way high output stators are made is with extra windings (higher voltage). They might get away with thinner wire and insulation by using better materials, but I suspect most of what they do is a lot of detail in how they're wound so they don't waste any space.

[reddevilmedic]

get a Shindigen, 3 phase r/r, wire it direct. i have the same setup...ricks hot shot, shindigen, ...got it right after i burned out 3 regular stators..

[Marcarl]

Shouldn't you be doing a continuity test across those 3 wires to see if there's a short in the stator? 1&3,,,, 3&2,,,,,1&2 type thing???? But them what do I know,,, I don't even change tires.

[Yammer Dan]

There was a group buy on those Shindigens. Wish I had got one. Sounds like it could be problem. Hey Muffin......

[reddevilmedic]

http://roadstercycle.com/Shindengen%20FH012AA%20Regulator%20upgrade%20kit.htm

[Flyinfool]

25V is not high, in fact it may be a little low.

 

First check all of the new connectors to be sure that the contacts are inserted fully.

 

Check it at above 2,000 RPM.

Make sure that your volt meter is set on AC and on a high scale, I use 200VAC scale.

Check each pair of wires. 1-2, 2-3, 1-3.

The voltage should be very close to the same on each pair.

Around 25VAC at idle is about right, It will rise to well over 50VAC at high RPMs. It is possible to be sneaking up on 100V.

 

WARNING

Be careful while doing these checks The unloaded stator at higher RPMs is outputting potentially dangerous voltage.

[djh3]

HUH I looked thru the sservice manual and that thing is worthless on TS the charging system in my book. It tells how to ohm it out but no voltage check other then at battery with everything hooked up.

It just so happens I had a stator go out on my 900 Vulcan. Way more common than it shoud be for those things. But anyways I was just on the Kawi fourm today involved in the TS of a stator issue for a fllow. On those it says run @ 5k rpm and reading across any combo of white leads (I'm guessing thats the common or something they are all across the bottom next to each other) is 54v. Dont know if this will help or not, but its more info than the Yamaha manual has.

[calperin]

Brad,

 

25 Volts AC is not the issue. Allways AC voltage will be higher than the final DC 14.1V

 

If it is not charging only two things can happen:

 

1st Rectifiers are not working or are not connected on a proper way.

2nd Voltage regulator is not working or input is not right.

 

Regards,

 

Carlos

[reddevilmedic]

http://roadstercycle.com/Stator%20Testing%20Example.htm. testing a vmax stator

[mbrood]

You've proven it's getting AC voltage (which should rise and fall with the RPM) but report no charge. I would use the Ohm meter (diode test function if it has it) and test the 6 diodes in the rectifier section of the R/R. Red to each alternator white, both ways, then black to each white, both ways. (There is no documentation for the regulator section)

[Squidley]

Thanks Fellas, I just wanted to be sure I hadn't put it together wrong and that's why I tested the VAC. It was at idle that I got the 25 Volts, I am going to reinstall the old/new R/R as I believe it was working fine, the stator burned up thus creating the charging issue. I'm a little stumped that the new Ricks R/R didn't work right, it's pretty stupid proof, or so this idiot (me) thought. There are only 5 wires on it, 3 yellow that hook to the stator wires, a heavy red which goes to the dual red of the bikes wiring harness and a black which hook to the bikes black in the harness.

I'll try the old R/R and if it charges properly I'll send this Ricks back to them for a different one.

[playboy]

Ac would be higher as the rectifiers change it from ac to dc. Half of 25 would be 12.5. So it may not be high enough. But it was 40 years ago I was learning about rectifiers so I could be,,, uh,,, forgetful...

 

 

Well I'll be learn something new all the time.

[frankd]

Test the stator and make sure it is NOT grounded. You only need to check 1 lead to ground....if the stator is grounded all 3 leads will measure to ground.

 

If it's not grounded the best way that I've found to test the stator is to connect three 115V, 75W incandescent lights across the 3 pairs (A to B, A to C, and B to C). All 3 should light equally when you bring the engine up to about 4,000 RPM. The last bad one that I replaced had intermittent shorted turns. It was NOT grounded, which surprised me. When I connected 3 light bubs across the 3 stator pairs (not connected to the R/R), when I first started it up, all 3 would light equally. Then after a minute or so, 2 of the light bulbs started going dim, and the 3rd was still reasonably bright.

 

To connect the light bulbs, I used the sockets with pigtail leads. These are the kind that the used car lots used to use in the early 60's. They also use them on some construction sites and they should be available at Home Depot or Lowe's.

 

Frank D.

[Flyinfool]

Ac would be higher as the rectifiers change it from ac to dc. Half of 25 would be 12.5. So it may not be high enough. But it was 40 years ago I was learning about rectifiers so I could be,,, uh,,, forgetful...

A rectifier is just 1 or more diodes. In this case, because it is 3 phase AC it is 6 diodes.

A typical rectifier diode will only drop about 0.6V each. Because in this case you are always using 2 at a time you will get a 1.2V drop from the AC to DC. There are different types of diodes that can be used with different characteristics, I am not sure which type are being used in our RRs, but the voltage drop will not be much different.

 

So the rectifier just changes the AC into DC with just a very small voltage drop.

It is the regulator part that knocks the voltage down to the 14 that we want.

[MiCarl]

So the rectifier just changes the AC into DC with just a very small voltage drop.

 

I started a post last night trying to say that, but it got out of hand with detail.

 

Most volt meters measure RMS voltage rather than peak voltage. RMS is an average which converts directly to DC (minus the losses Jeff mentioned).

[Gray Ghost]

For what it is worth, this is what Harley teaches on charging systems. Check the battery voltage with key off, then check the voltage with the bike running. If that voltage is higher, the system is putting out voltage to the battery.

 

The next checks are: Disconnect stator at the R/R and check the three legs (1-3, 1-2, 2-3) at 2000 RPM. That should be 32 - 46 VAC. Since Yamaha didn't give us values for that, the option is to check all three at 1000 RPM, then at 2000. The reading should be fairly consistent across the legs, and the 2000 reading should be about double the 1000. Significant differences between the legs means that you have a problem with the stator. Low voltages, but consistent across all the legs means a problem with the rotor.

 

Next test is continuity between the legs (should be less than 1 ohm), as has already been pointed out. Then check for stator to ground (should be open).

 

On newer Harleys they don't actually check the R/R. If the first three tests are good, they test continuity from the R/R back to the battery. If that is good, they replace the R/R.

[calperin]

The higher the RPM goes, the higher of the VAC you will read until you got the point that increasing RPM will not increase the reading on VAC.

 

The instrument will integrate the reading, and as the RPM is high enough will reach the max output of the stator.

[GeorgeS]

With everything hooked up, engine running. At the Plug between Stator, and R/R unit. Stick meter lead into the Plug, one of the 3 phases at a time.

Read AC voltage to ground.

Take Three readings, for each phase.

 

They should all be about the Same AC voltage, it will vary with Engine RPM.

 

IF one of the three, is Lower then the other two, then the Stator most likley is bad.

 

IF, All read same voltage, the Double Check every Inch of Wireing, from Stator to R/R Unit.

You might have missed, a damaged wire !!! ( Well maby )

 

--- Is your large White plug Damage ????? This is common, Burnt Pins in the plug.

( But I'm sure you knew that, so ??? )

 

Inspect the Output plug carefully from the R/R unit, possible damaged plug there.

 

Make sure the Black, Ground , OUTPUT wire from the R / R Unit, is Actually grounded !!! on 86, that main ground point, is buried Under the Upper Left Side Fairing . ( Not easy to get to )