measuring stator voltage

[Crusherxr]

I am new. Great site, been doing alot of reading. My question is about measuring the AC voltage at the stator. I have read that you can measure this voltage by measuring across 2 white wires, and also that you can measure it by the red lead on a white wire, and the black lead on ground.

If you can measure the stator both ways , could you tell me the voltage reading I would get?

Thanks very much!

 

[Buster Hymen]

I believe you should be getting around 50 to 60 volts AC.

 

[Crusherxr]

With the leads in which place?

 

[maleko89]

Disconnect the stator. Should be 50-75 VAC at about 2500 rpms.

 

[Crusherxr]

Do I measure between 2 white wires or 1 white wire and ground.....

 

[maleko89]

3 tests, each between the white wires. I was wrong before, ref to 5K rpms and should get a minimum of 50 VAC.

 

[naughtyG]

Indeed, as it is AC (not DC like the 12V battery) you simply test between any two of the three white wires, and repeat the test 3 times to make sure you tried every combination as this will show you all 3 stator windings are working. If the voltage goes well past 55-60V as you rev up to 5000rpm and above, it also means your stator is fried and won't charge properly.

I had readings of up to 75V on my old '86 and it was bust.

 

[thor_eyerdhal]

Mine has always shown 75-80V above 4000 rpm...

Are you sure this is an issue??

 

[sdt354]

High resistance in the plug from the stator to the R/R is a common issue too. A lot of them get cut out and soldered.

 

[Crusherxr]

Thanks for the help. I measured each wire to ground at 3k Rpms and they measured 37volts. Found that my Rectifier is only putting out 12.4vdc at idle and 12.6 at 2k Rpms. Going to replace the rectifier with a fiinned one.

 

[davidon]

Thanks for the help. I measured each wire to ground at 3k Rpms and they measured 37volts. Found that my Rectifier is only putting out 12.4vdc at idle and 12.6 at 2k Rpms. Going to replace the rectifier with a fiinned one.

Finned VMAX one or Mosfet? use the Mosfet for best results

 

[Crusherxr]

A Vmax one.

 

[jfeagins]

Sean Morley carries the upgraded finned ones that are nearly an exact replacement for OEM. All you have to do is buy two longer bolts to attach to the OEM location, and run it's black ground wire over to a secure frame bolt.

It's what I did and was easy peasy.

 

[naughtyG]

Thanks for the help. I measured each wire to ground at 3k Rpms and they measured 37volts. Found that my Rectifier is only putting out 12.4vdc at idle and 12.6 at 2k Rpms. Going to replace the rectifier with a fiinned one.

You should be measuring AC between the wires - not wire to ground. That's why you take three measurements, to make sure you try every combination of two wires: wire 1 + 2, 1 + 3, and 2 + 3.

37V AC is a little low, try revving up a bit more and you should see 50V AC with a healthy stator.