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FS600V w/ no regulator or stator?
#1
I
imagineer
I
imagineer
I have a SCAG 52" walk-behind, hydraulic drive with a Kawasaki FS600V engine and the electric clutch stopped working. I checked the voltage at the wire that I assumed was the output from the voltage regulator and at idle it's outputting 1.7vdc and at full throttle, its putting out about 2.1vdc. So my assumption is the voltage regulator is bad. I took the engine cover off to identify it for a replacement and...there's no voltage regulator. There is a small wire attached to a spade connector on each coil, they're spliced together and a single wire goes to the mower harness (via a bullet connector). This engine also does not appear to have a stator, rather has a simple magneto. There is a single wire coming from under the flywheel, but my understanding is stators have 2 (or 3) wires.
Am I correct in that there is a diode in each coil, and the output from these diodes is the DC voltage used to power the electric clutch? I have replacement coils on order, but I'm curious if there's something else I should be looking it?
Am I correct in that there is a diode in each coil, and the output from these diodes is the DC voltage used to power the electric clutch? I have replacement coils on order, but I'm curious if there's something else I should be looking it?
#2
A
Auto Doc's
A
Auto Doc's
This sounds like the basic engine has been changed at some point for one with a direct AC charging system and inline diode for battery charging. These do not put out nearly enough amperage to operate an electric PTO for any considerable amount of time.
#3
T
txmowman
T
txmowman
What you have is called a clutch coil. It generates AC voltage but then goes through a pair of diodes that convert the AC to DC to power the clutch. The DC voltage is then “regulated” by the load applied. So, the red wire, unregulated, should read 30+ VDC normally. If not, either the coil is shorted or there is damage to the magnets inside of the flywheel.
#4
T
txmowman
T
txmowman
This sounds like the basic engine has been changed at some point for one with a direct AC charging system and inline diode for battery charging. These do not put out nearly enough amperage to operate an electric PTO for any considerable amount of time.
#5
I
imagineer
I
imagineer
I got lucky and found the service manual. On the FS600V, set up for recoil start, there is a stator under the flywheel and it appears to have a single wire. I'll put the mover back together, get it started and check the voltage at the single wire from the stator.
Also, per the service manual, the recoil stator should have resistance 4.4 to 15 ohms. Given that it's a single wire stator, do I check the resistance between the single wire and a ground point?
Also, per the service manual, the recoil stator should have resistance 4.4 to 15 ohms. Given that it's a single wire stator, do I check the resistance between the single wire and a ground point?
#6
T
txmowman
T
txmowman
Its job is to put out to operate the load for as long as needed.This sounds like the basic engine has been changed at some point for one with a direct AC charging system and inline diode for battery charging. These do not put out nearly enough amperage to operate an electric PTO for any considerable amount of time.
#7
I
imagineer
I
imagineer
Thanks. I was checking the voltage at the yellow wire, which is what grounds out the ignition coils to shut off the engine. I'll put it back together tomorrow and check the voltage at the red wire.What you have is called a clutch coil. It generates AC voltage but then goes through a pair of diodes that convert the AC to DC to power the clutch. The DC voltage is then “regulated” by the load applied. So, the red wire, unregulated, should read 30+ VDC normally. If not, either the coil is shorted or there is damage to the magnets inside of the flywheel.
#8
A
Auto Doc's
A
Auto Doc's
Hi txmowerman,
I have not seen many single wire stators produce 30+VDC. The stator only produces AC current from the rapidly changing polarity of the spinning magnets attached to the flywheel. Maybe there is a diode hidden in the stator harness I'm not aware of. These were low amperage stators
I've certainly not seen models with an electric PTO clutch and a single wire stator. They don't produce enough amperage to hold the clutch engaged for any length of time. I'm curious how this turns out, because I certainly don't claim I've seen everything.
I've seen the 2-wire stator design produce 30+VAC and then it was converted to DC by the external voltage regulator mounted to the sheet metal for a good ground. Or, they had a separate ground attached to the regulator housing.
I have not seen many single wire stators produce 30+VDC. The stator only produces AC current from the rapidly changing polarity of the spinning magnets attached to the flywheel. Maybe there is a diode hidden in the stator harness I'm not aware of. These were low amperage stators
I've certainly not seen models with an electric PTO clutch and a single wire stator. They don't produce enough amperage to hold the clutch engaged for any length of time. I'm curious how this turns out, because I certainly don't claim I've seen everything.
I've seen the 2-wire stator design produce 30+VAC and then it was converted to DC by the external voltage regulator mounted to the sheet metal for a good ground. Or, they had a separate ground attached to the regulator housing.
#9
T
txmowman
It can be seen where each winding goes through a diode. Then the two windings become one red wire to the clutch.
This information is sourced from Kawasaki KTech training. Every technician who works for a Kawasaki dealership should attend this. It is great, and I always learn something.
T
txmowman
Yes. I would check continuity. If there isn’t any, it is aI got lucky and found the service manual. On the FS600V, set up for recoil start, there is a stator under the flywheel and it appears to have a single wire. I'll put the mover back together, get it started and check the voltage at the single wire from the stator.
Also, per the service manual, the recoil stator should have resistance 4.4 to 15 ohms. Given that it's a single wire stator, do I check the resistance between the single wire and a ground point?
Hi Auto Docs, The coil is actually two separate windings (see attached). Each winding creates full-wave AC. The AC then goes through a diode and gets converted to half-wave pulsating DC. These two half-waves then come together as a full-wave pulsating DC that flows into the load.Hi txmowerman,
I have not seen many single wire stators produce 30+VDC. The stator only produces AC current from the rapidly changing polarity of the spinning magnets attached to the flywheel. Maybe there is a diode hidden in the stator harness I'm not aware of. These were low amperage stators
I've certainly not seen models with an electric PTO clutch and a single wire stator. They don't produce enough amperage to hold the clutch engaged for any length of time. I'm curious how this turns out, because I certainly don't claim I've seen everything.
I've seen the 2-wire stator design produce 30+VAC and then it was converted to DC by the external voltage regulator mounted to the sheet metal for a good ground. Or, they had a separate ground attached to the regulator housing.
It can be seen where each winding goes through a diode. Then the two windings become one red wire to the clutch.
This information is sourced from Kawasaki KTech training. Every technician who works for a Kawasaki dealership should attend this. It is great, and I always learn something.
Attachments
#10
I
imagineer
I
imagineer
Solved it! Long story shortened, all it needed was the 3 clutch adjustment bolts tightened.
How I got there...
Reassembled and started the mower. Checked voltage at the single wire from the stator, 17 VDC at idle and up to 37 VDC wide open.
Resistance checked the clutch, 1 ohm. Depending on the resource it was either within or close to an acceptable reading.
With the mower off, I applied 12VDC from a spare motorcycle battery and the clutch made a noticeable click.
With the mower running, I checked the voltage at the clutch plug, matched the voltages off the stator wire.
While the motor was running and I was cycling the clutch switch, I noticed the blade spindles move just a smidge (like maybe 1/2 degree).
All this made me think the mower's electrical system was fine and that the clutch was simply weak.
Got on line and wasn't able to find a definitive option specific for my mower. I checked the Scag user manual to see if they called out the clutch part number. They don't, but I did notice a description for how and why to adjust the clutch. One thing I neglected to mention earlier was that while the mower was in use previously, it seemed that when the PTO switch was engaged, it was taking too long for the blades to get up to speed (i.e., the clutch was slipping).
Per the Scag manual, there should be a .015" gap measured using a site hole in the clutch. I found that the gap on my clutch was about .035". The 3 adjustment bolts are 3/8-16 thread, so to take up the .020" slop in the clutch would require just over 1/4 turn on the adjustment bolts.
Adjusted the bolts and, voila, it worked perfectly!
How I got there...
Reassembled and started the mower. Checked voltage at the single wire from the stator, 17 VDC at idle and up to 37 VDC wide open.
Resistance checked the clutch, 1 ohm. Depending on the resource it was either within or close to an acceptable reading.
With the mower off, I applied 12VDC from a spare motorcycle battery and the clutch made a noticeable click.
With the mower running, I checked the voltage at the clutch plug, matched the voltages off the stator wire.
While the motor was running and I was cycling the clutch switch, I noticed the blade spindles move just a smidge (like maybe 1/2 degree).
All this made me think the mower's electrical system was fine and that the clutch was simply weak.
Got on line and wasn't able to find a definitive option specific for my mower. I checked the Scag user manual to see if they called out the clutch part number. They don't, but I did notice a description for how and why to adjust the clutch. One thing I neglected to mention earlier was that while the mower was in use previously, it seemed that when the PTO switch was engaged, it was taking too long for the blades to get up to speed (i.e., the clutch was slipping).
Per the Scag manual, there should be a .015" gap measured using a site hole in the clutch. I found that the gap on my clutch was about .035". The 3 adjustment bolts are 3/8-16 thread, so to take up the .020" slop in the clutch would require just over 1/4 turn on the adjustment bolts.
Adjusted the bolts and, voila, it worked perfectly!
#11
ILENGINE
ILENGINE
Need to double check that ohm reading. Because if that 1 ohm is accurate that clutch is pulling 12 amp. Resistance should be in the 2.3-3.3 ohm range. Normal clutches pull 2.5-5 amp normally with some closer to 6 amp which would be a mininum of 2 ohm resistance.Solved it! Long story shortened, all it needed was the 3 clutch adjustment bolts tightened.
How I got there...
Reassembled and started the mower. Checked voltage at the single wire from the stator, 17 VDC at idle and up to 37 VDC wide open.
Resistance checked the clutch, 1 ohm. Depending on the resource it was either within or close to an acceptable reading.
#12
A
Auto Doc's
People think that 12V on a meter equals "power", but they have no concept of the amperage required to hold the clutch plate engaged. If a .5 Amp simple test light works does that mean everything is good. I think not!
Voltage is just expected potential.
Amperage is the actual (power) work. It requires an Amp clamp to measure, which most people don't own.
Resistance exists to challenge the system to work by creating a load to "excite it to work".
Sounds too simple, but it is honest.
Low wiring resistance in a clutch winding (2-5 Ohms) is normally the potential to apply the work according to how it is wound and insulated. Too low or zero means an open in the windings. Very high resistance usually means a meltdown of the field wiring shellac insulation coating.
Ohms law and Kirchhof's law is the most unlearned among many in the repair industry. That is why engineers are running most people in circles these days. I see it in the automotive industry as well.
A
Auto Doc's
It never fails.Need to double check that ohm reading. Because if that 1 ohm is accurate that clutch is pulling 12 amp. Resistance should be in the 2.3-3.3 ohm range. Normal clutches pull 2.5-5 amp normally with some closer to 6 amp which would be a mininum of 2 ohm resistance.
People think that 12V on a meter equals "power", but they have no concept of the amperage required to hold the clutch plate engaged. If a .5 Amp simple test light works does that mean everything is good. I think not!
Voltage is just expected potential.
Amperage is the actual (power) work. It requires an Amp clamp to measure, which most people don't own.
Resistance exists to challenge the system to work by creating a load to "excite it to work".
Sounds too simple, but it is honest.
Low wiring resistance in a clutch winding (2-5 Ohms) is normally the potential to apply the work according to how it is wound and insulated. Too low or zero means an open in the windings. Very high resistance usually means a meltdown of the field wiring shellac insulation coating.
Ohms law and Kirchhof's law is the most unlearned among many in the repair industry. That is why engineers are running most people in circles these days. I see it in the automotive industry as well.