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Bad Rectifer taking out a Stater?

6K views 18 replies 8 participants last post by  BradS 
#1 ·
Is it possible for a defective rectifier to kill a stater?
 
#2 ·
Yes it could , but as to how likely that's hard to say .
 
#6 ·
Heres some info I found on the subject.


Rect Diodes can only fail one of 2 ways
Open or Closed

Open is a road to nowhere,,,same as if you'd cut the stator wires.

How many "Dirt Bikes" ya think there are in the world,,,Stripped of EVERYTHING possible,,,,,,while the generator whirls away?
Gazillions run like that for Years and Years.

Then somebody Reconnects the Lights,,,and Voila!,,they work fine.
Which proves that a Failed Open Rectifier is harmless to a stator.

A Failed Closed Rectifier Diode,,,it dont care either
It spends half it's life Blocking current,,,and Other half Passing current.
Passing current is a LOT less load than Blocking it.

A failed Rect Diode behaves like merely an extension of the output wire from the Stator.
No Longer a Semi-Conductor,,,it becomes a Full Conductor

Stator dont care if it's wires are 16" long or 16.01".

The trouble is a Closed Diode passes Both sides of the AC wave

Stator OutPut goes Thru Rectifier then Straight to the Battery

If Rectifier is Not Rectifyin' the AC into DC,,,,
WHICH type of Current is the Battery Getting?

Yeah,,,AC.

What does AC do to the battery?

Ever Crosswire Jumper Cables?
Connect Positive directly To Ground?
Grand Mal SHORT.
That's as Short Circuit as ya can get

AC Into a Battery,,,gets Shorted at BOTH Poles on an alternating Basis,,,every cycle swing
Positive Pole gets hit with Negative Polarity
and an instant later
Negative Pole gets hit with Positive Polarity
Does that several dozen times per second.

Like a Tug-o-war of electrons trying to charge the Batt.

It'll eventually Kill any battery.I dont mean Drain it as in "dead Battery"
I mean KILL as in Mortally Wounded.

Obvious question is Why not Immediately?
How can a Batt take that abuse for Days before Dying?

That's complicated.
Simple version includes 2 main principles.
#1 is because a Batt is Constructed to produce a certain polarity and will persist in that function untill it's electrolytic capability is destroyed.

#2 is odd,,,,but even with AC input the Batt is getting SOME small semblance of a charge
At the batts Positive Pole,,it get a Half of the AC wave cycle in proper phase,,,before it Reverses into Negative polarity

So it DOES get a Pulse of Positive Current at the Positive terminal

It Also get a Pulse of Negative Charge at the Negative terminal,,,before IT reverses to Opposite Polarity

And for a very brief instant,,,,On the AC Sine wave,,between the Peak + and Trough -,,,
there exists a Baseline of ZERO Polarity.
And for that brief instant,,,there's No countermanding polarity to oppose what's going into the battery at the moment on a particular terminal.

Gets even more complex with 3phase generator,,,and multi poles.
That's about the point where It's over my head and I quit,,,and leave it to the engineers & take there word for it.
(Meaning Lots of Smile & Nod & pretending I have even a faint Idea what they just said)

Anyway,,,NO a Rectifier cannot really damage a Stator
And Yes,,a Battery can SEEM fine,,,and within a Few days not only be drained but Destroyed.

Simple answer is,,,Replace your Rectifier.
You can test Stator Output according to Repair Manual if you want to.

Battery,,,,,odds are it needs to be replaced also.
You can TRY Charging it--never hurts to Try.
And plenty enough ARE saveable to suggest Charging is worth a try and not totally impossible

Hope any of that gibberish makes any sense

The Theory of everything involved fills entire sections of Libraries.
The Practical application,,,and testing and trouble shooting would fill a small book.
Then when it comes down to What Ya can Do about it,,,you can write it all on a business card.

Test Stator,,,repair or replace if necessary
Test Regulator/rectifier,,,replace if Necessary
Test Battery,,replace if necessary
 
#7 ·
A bad regulator/rectifier might damage a stator. The rectifier, besides rectifying the AC from the stator into DC for the system, also shorts some of the output to ground (usually through SCRs but some newer models use MOFSETs) to control the output voltage. In a permanent mag system, the stator outputs all it can all them time. The output is based generally on the RPM of the rotor. The faster the rotor is turning the more the system produces.

If the regulator is shorting more to ground than it should (system voltage would probably be down) then the stator would likely see a lower than ordinary resistance to ground which might cause it to run hotter than it should and at some point could cause the premature breakdown of insulation on the windings (just a thin shellac) and cause them to short together lowering output.
 
#11 ·
I'm not sure it's possible for a stator to put out more than the book by very much. It might do maybe 20 or 30 volts more but not more than 3 times. I would suspect the meter or the meter setting. Make sure to use AC volts and check each of 3 pairs (1-2, 2-3, 1-3) unplugged from the regulator.
 
#10 · (Edited)
Do you have a tach on the bike , to confirm the speed to charge ratio ? Originally I mis read part of this . Also are you sure you have the right setting on your meter ?
 
#13 ·
I used 3 meters because I didnt believe it myself.... I know how to test the stator... Even watched the video 3 times before testing it to make sure....

Im going to test it one more time to make sure... and yes I know to use the AC setting on the meter
 
#16 ·
The ohms between phases probably won't tell you much. As long as you don't have any that are grounded then the stator isn't shorted to the core. Even though you could have some windings shorting to themselves, that would lower the voltage output, not raise it.

The only way it could be putting out more than the book value is to increase the number of winds of wire on each stator post or to increase the magnetic field of the rotor. To get more than 3 times the rated voltage would require a LOT of extra winds of wire or a massive increase in the magnetic field. To get that much wire on the stator means to have to use much smaller wire. There's just not room to put additional wire on unless you drop the size. I can't imagine that your stator was wound with much more wire of a smaller size than every other 109 stator. And, it would have been that way from the factory. Doubtful.

Not sure what the issue is at this point. I've tested and replaced a lot of stators and can say that they never put out more than 20-30 volts more than the book even when wound with some extra wire. As they age, the output drops as the windings short to themselves and sometimes to the core as the insulation breaks down due to heat.
 
#17 ·
I just got a safety recall notice in the mail for the regulator/rectifier cover by Suzuki no cost to us
 
#18 ·
Just got a RECALL NOTICE from Suzuki today in the mail on this very subject. They know I exist. They may not know that you exist. Here are the instructions:

Go to suzukicycles.com
Select SAFETY RECALLS at the lower right side of the home page.
When the page refreshes, select RECALL NOTIFICATION LETTERS.
Select RECTIFIER REIMBURSEMENT.

Again, just got this in the mail today from Suzuki.

Good luck.
 
#19 ·
I know about the recall..... But my Stator is bad..... I have a new rectifier that I have not put on because I dont want to burn it up as well. Im going to call the dealer Tuesday and set up an appointment to have them replace the rectifier and see if they have an issue with the Stator as well.
 
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