Regulator Wiring Diagram

[WVHillbilly520H 10,369]

@cleat, maybe he can shed some 💡 on this subject, As I believe he likes to rewire to the first product style.

[cleat 4,936]

The old style 520's (88 and 89) has 2 fuse holders mounted on the bracket that holds the front of the belt guard.

 

The charge fuse (30A) is located close to the starter solenoid.

 

If you keep blowing this fuse then I would suspect the wire from the regulator down to the 30A fuse.

 

There is a good chance somebody has pinched it in the exhaust, intake, or some other bolt and shorted it to ground.

 

I don't know if this has destroyed the regulator or not.

 

You could run a wire directly from the center regulator terminal dup to the battery + terminal with an inline fuse for safety and see what happens.

 

Also with the center wire unplugged from the regulator and 30A fuse removed, do an ohms check between that wire and ground.

It should be infinite or open. If it is close to zero then you know the wire is grounded out somewhere.

 

Here is the early model wire diagram Wheel horse 520H wire diagram.pdf

 

Cleat

 

 

[jimr 1]

I went to the owners house today to measure the Stator resistance.  Removing the wires from the regulator I read 0.2 ohms across the Stator.  Somewhat in the region of what the manuals states.  Then I measured from the White wire to ground, it read 30 ohms.  From what I can gather from the instructions, this should be an Open.  Even though the schematics show a connection to ground I think they are incorrect.  

Found the 20 Amp Stator new for $64.  Since the main fuse is 30 Amp I see no reason to spend the extra and get the 35 amp Stator.  I also ordered another Regulator from a vendor on ebay.

 

I'll just wait for all the parts to arrive before pulling the flywheel.

 

Merry Christmas,

 

Dan K.

[jimr 1]

Today I started on the replacement of the stator.  For those that have not done this, it takes quite a bit of parts removal to get at the flywheel. The outer shroud is held in place with 9 bolts. The 6 on the outer perimeter are easy to remove, the 3 holding the coil assembly take some work to get out.  After all the cables and rubber parts are removed you still have to force the shroud off the engine.

Next comes the removal of the flywheel.  I had to make a trip to the hardware store to obtain 2 grade 8 bolts.  The softer bolts in the puller kit bent when I applied the impact wrench.  You have to break the main flywheel bolt free from the shaft and after installing the wheel puller you have to hold the 5/8" bolt while using the impact wrench.  It took quite a while for the flywheel to release but it did with a bang.

The stator removal was easy, 3 bolts and pulled the harness out of the clamps.  I installed the new stator, snaked the wires through the frame and then cleaned all the debris from between the flywheel magnets.  I don't know if that is required but since it was apart, why not.

Reassembling the flywheel and using the impact wrench assured the shaft bolt was tight.

 

After fully assembling all the shroud parts I placed my voltmeter on the two leads from the stator before connecting to the regulator.  Started the engine and measured about 18 volts AC.  Increased the engine RPM and the voltage went up to 30 VAC.  I was pleased with that.  Then I connected the stator wires to the regulator and started the engine.  I measured the DC output of the regulator without the wire  connection to the DC terminal.  Much to my displeasure I read -2.3 VDC. I could not figure why I was getting this reading. Just to see if the regulator needed a load, I connected the DC wire and installed a 20 Amp fuse in the charge circuit and restated the engine while monitoring the battery voltage.  A smile came over my face as I saw the battery voltage slowly climbing. It stopped at 14.65 VDC and maintained this while the engine ran at mid throttle.  Slowing down to idle the charging was still going on at 13.5 volts.

 

One thing I did besides replacing both the stator and regulator was to disconnect the wire that goes to the tachometer.  Since there is no definitive schematic that shows which terminal on the regulator the tach goes to, and the owner never uses the tach, the disconnected wire  does not present any missing feature.  At least now the battery will be charging during normal operation.  I suggested and the owner purchased a trickle charger to maintain the battery while in storage.

 

This was a long and frustrating repair but at least it is complete and operational.  Thanks to all for the suggestions and documentation that led me to a successful outcome.

 

Regards,

Dan K

[cleat 4,936]

Can you see any obvious issues with the original stator (like missing insulation, melted wires etc.).

 

Glad all is well now, never heard of this issue before but I guess there is a first for everything.

 

Cleat

[WH nut 553]

On 12/20/2018 at 11:16 AM, jimr said:

Still thinking about the problem of blowing regulators and 30 Amp fuses and I looked at the wiring diagrams of other years.  The tractor I am working on is a 1988 model, the wiring of the 1990 model shows the Tach wire going to one of the AC posts on the regulator.  This seems much more consistent with how I think the tach should work.  The configuration as I received was with the Tach wire (Gray) connected to the B+ output of the regulator.

Also some of the individual circuit diagrams show the Stator not connected to ground where others show a ground connection.

Does anyone know which is correct?  If there is supposed to be NO connection to ground of the Stator, then this tractor may have a short on the Stator.  If it is supposed to be grounded, what should the resistance be between each leg to ground and between the legs with the regulator removed? 

Trouble shooting this charging system is quite simple. You have already verified the stator is good. Try running a fused jumper from bat + to the center terminal on the regulator. If its shows no charge its the regulator. if it charges you have bad wiring from Ignition to regulator. All you need is 12v to the center terminal

[WH nut 553]

On 12/20/2018 at 11:16 AM, jimr said:

Still thinking about the problem of blowing regulators and 30 Amp fuses and I looked at the wiring diagrams of other years.  The tractor I am working on is a 1988 model, the wiring of the 1990 model shows the Tach wire going to one of the AC posts on the regulator.  This seems much more consistent with how I think the tach should work.  The configuration as I received was with the Tach wire (Gray) connected to the B+ output of the regulator.

Also some of the individual circuit diagrams show the Stator not connected to ground where others show a ground connection.

Does anyone know which is correct?  If there is supposed to be NO connection to ground of the Stator, then this tractor may have a short on the Stator.  If it is supposed to be grounded, what should the resistance be between each leg to ground and between the legs with the regulator removed? 

Trouble shooting this charging system is quite simple. You have already verified the stator is good. Try running a fused jumper from bat + to the center terminal on the regulator. If its shows no charge its the regulator. if it charges you have bad wiring from Ignition to regulator. All you need is 12v to the center terminal

[WH nut 553]

On 12/20/2018 at 11:16 AM, jimr said:

Still thinking about the problem of blowing regulators and 30 Amp fuses and I looked at the wiring diagrams of other years.  The tractor I am working on is a 1988 model, the wiring of the 1990 model shows the Tach wire going to one of the AC posts on the regulator.  This seems much more consistent with how I think the tach should work.  The configuration as I received was with the Tach wire (Gray) connected to the B+ output of the regulator.

Also some of the individual circuit diagrams show the Stator not connected to ground where others show a ground connection.

Does anyone know which is correct?  If there is supposed to be NO connection to ground of the Stator, then this tractor may have a short on the Stator.  If it is supposed to be grounded, what should the resistance be between each leg to ground and between the legs with the regulator removed? 

Trouble shooting this charging system is quite simple. You have already verified the stator is good. Try running a fused jumper from bat + to the center terminal on the regulator. If its shows no charge its the regulator. if it charges you have bad wiring from Ignition to regulator. All you need is 12v to the center terminal

[WH nut 553]

Oopps I see you got it

[jimr 1]

Today I started on the replacement of the stator.  For those that have not done this, it takes quite a bit of parts removal to get at the flywheel. The outer shroud is held in place with 9 bolts. The 6 on the outer perimeter are easy to remove, the 3 holding the coil assembly take some work to get out.  After all the cables and rubber parts are removed you still have to force the shroud off the engine.

Next comes the removal of the flywheel.  I had to make a trip to the hardware store to obtain 2 grade 8 bolts.  The softer bolts in the puller kit bent when I applied the impact wrench.  You have to break the main flywheel bolt free from the shaft and after installing the wheel puller you have to hold the 5/8" bolt while using the impact wrench.  It took quite a while for the flywheel to release but it did with a bang.

The stator removal was easy, 3 bolts and pulled the harness out of the clamps.  I installed the new stator, snaked the wires through the frame and then cleaned all the debris from between the flywheel magnets.  I don't know if that is required but since it was apart, why not.

Reassembling the flywheel and using the impact wrench assured the shaft bolt was tight.

 

After fully assembling all the shroud parts I placed my voltmeter on the two leads from the stator before connecting to the regulator.  Started the engine and measured about 18 volts AC.  Increased the engine RPM and the voltage went up to 30 VAC.  I was pleased with that.  Then I connected the stator wires to the regulator and started the engine.  I measured the DC output of the regulator without the wire  connection to the DC terminal.  Much to my displeasure I read -2.3 VDC. I could not figure why I was getting this reading. Just to see if the regulator needed a load, I connected the DC wire and installed a 20 Amp fuse in the charge circuit and restated the engine while monitoring the battery voltage.  A smile came over my face as I saw the battery voltage slowly climbing. It stopped at 14.65 VDC and maintained this while the engine ran at mid throttle.  Slowing down to idle the charging was still going on at 13.5 volts.

 

One thing I did besides replacing both the stator and regulator was to disconnect the wire that goes to the tachometer.  Since there is no definitive schematic that shows which terminal on the regulator the tach goes to, and the owner never uses the tach, the disconnected wire  does not present any missing feature.  At least now the battery will be charging during normal operation.  I suggested and the owner purchased a trickle charger to maintain the battery while in storage.

 

This was a long and frustrating repair but at least it is complete and operational.  Thanks to all for the suggestions and documentation that led me to a successful outcome.

 

12/29/18

Just thinking about this more, I believe the problem is due to the incorrect connection of the tach to the regulator.  When I installed the new stator and connected the stator to the regulator the output of the regulator was -2.3 volts with the engine running.  Seems the regulator needs a load.  Since the tach was incorrectly connected to the DC out port and that came directly from the battery through the 30 Amp fuse, if the tach was supposed to go to the AC port than it blew the 30 Amp fuse and the regulator went into a No Load state.  When I removed the tach wire from the regulator all was good.  As it turned out, the regulator I thought was bad, I re-installed into the tractor and after the correct connections, this worked fine.  I now have a new regulator for stock.

Regards,

Dan K

[jimr 1]

Inspecting the stator revealed a lot of caked on material.  Probably a combination of oil residue and grass clippings.  Someone at some previous time had spliced a section of wire at one end.  The connector plastic was melted and the metal connector appeared to have some corrosion. Measuring the stator resistance out of the engine did not show anything between either lead and the metal frame of the stator.  Why it read 30 ohms at one point is a mystery.

 

I guess the most important piece of information from this overall investigation was that the regulator will output a slight negative voltage when not connected to a battery load.  When the 30 amp fuse blew, the battery was disconnected from the regulator and a measurement of the regulator output gave an indication the regulator was fried.  I think I read somewhere the regulator is short circuit protected so the negative reading is just "normal" operation of this regulator when unloaded.

 

To make things more confusing was the incorrect wiring of the tachometer to the regulator.  I also think someone during some rework incorrectly placed the tachometer on the DC output of the regulator. This was probably the root cause of the fuse blowing.  Either the tach is bad or it can only operate above ground.  If I ever want to punish myself again, I may try the tach on one of the AC terminals of the regulator.  But at this point since it is charging I'll leave it alone.

Happy New Year to all on this forum.

 

Regards,

Dan K.

[gwest_ca-(File Mod) 10,478]

The regulator must see battery voltage before it can regulate the current. Some tractors even have a decal on them warning against running them without a charged battery in place.

It makes sense the tach requires AC current. We have learned some regulators have one of the AC leads tied to the DC output inside the regulator. I don't know if that is the same on all regulators but if so which AC lead used for the tach signal makes a difference.

Try using a test lamp between the AC terminals and the tach. The bulb should save doing any further damage and may identify which AC terminal makes it work.

 

Garry