Quantcast

measuring stator voltage

Yamaha Star V-Max VMAX Motorcycle Discussion Forum

Help Support VMAX Forum:

Crusherxr

Member
Joined
Jul 17, 2013
Messages
15
Reaction score
1
Location
Westphalia,Mi
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

Administrator
Staff member
Admin
Joined
Mar 28, 2006
Messages
4,209
Reaction score
12
I believe you should be getting around 50 to 60 volts AC.
 

maleko89

Moderator
Joined
Mar 30, 2006
Messages
6,567
Reaction score
26
Location
Gretna, NE
3 tests, each between the white wires. I was wrong before, ref to 5K rpms and should get a minimum of 50 VAC.
 

naughtyG

Well-Known Member
Joined
Jul 31, 2008
Messages
6,437
Reaction score
7
Location
Freo, Western Australia
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.
 

sdt354

Well-Known Member
Joined
Aug 8, 2008
Messages
5,871
Reaction score
122
Location
Southern N.E.
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

Member
Joined
Jul 17, 2013
Messages
15
Reaction score
1
Location
Westphalia,Mi
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

Well-Known Member
Joined
Apr 6, 2006
Messages
1,566
Reaction score
2
Location
Gaithersburg, MD
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
 

jfeagins

Well-Known Member
Joined
Aug 18, 2006
Messages
3,960
Reaction score
1
Location
..
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

Well-Known Member
Joined
Jul 31, 2008
Messages
6,437
Reaction score
7
Location
Freo, Western Australia
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.
 

Latest posts

Top