So I have this mid 90's MTD Tractor that has been converted from a riding mower to strict use as a winter snow blower as I got sick and tired of swapping blower and deck back and forth twice a year.
With a usual slowdown at work around this time of years, I started tackling this tractor with several fix ups and upgrades. I purchased a very good quality set of LED lights and mounted them after I yanked out the OEM bulbs and OEM reflector and tossed them for a field goal. I also added a 6 way set of strobing emergency lights, installed a 1,000 lbs strap winch for raising and lowering blower, tossed out OEM amp meter and installed an LED voltage/amp digital meter. Also custom mounted a full sized car battery for more CCA and rear weight.
After all this, I investigated into the charging system to see how she works. (B&S actually has lots of very nicely written and well documented information on their equipment in pdf files) I was disappointed to find out I won't yield optimum results with the current setup. The factory tractor is perfectly fine for running wimpy incandescent lights (which are ok for mowing lawn in the dark in summer), and is ok for charging the battery. Basically, I have the world famous dual circuit alternator.
This is basically two halves of two of their other alternators side by side. One side produces a/c power strictly for the lights. Other side produces a/c power as well, but is instantly tossed into a diode to change it to dc current for charging the battery. (This clearly doesn't provide me enough power by the fact my voltage drops to 12.0v when my lights are on). When all lights are off, I'll see a voltage as high as 17 at the higher rpm... The single diode is really not the smartest way we could be charging a battery.
Since Everything I added electrically requires DC power, I'm WAY down on amps, and have half the alternator doing nothing. :tango_face_sad: So looking over B&S' list of alternators, I was able to see I do have options. They have a somewhat expensive regulator that directly plugs into this alternator (with the removal of the exsiting diode) to then make it into a full dc regulated charging system. ( I still found this to be somewhat mickey mouse since we have two different gauge sizes of wire and turns going into the voltage regulator)
So a good chunk of us have a 696459 dual circuit alternator. I was now eyeballing the direct fit 696458 that can produce 10 amps on the flywheel with small magnets (flywheel most of us have). Or 16 amps if we have the flywheel with the larger magnets. Add in the 16 amp voltage regulator and we're good to go.
Now I'm also looking to upgrade my other MTD lawn tractor to LED lights and want to improve its charging system to use a real voltage regulator. Instead of purchasing two 696458 alternators, I decided to tackle rewinding one with some magnet wire I have laying around, and use the heavier gauge wire on one side to transform the other alternator from a 696459 to 696458. Then I just need to purchase some regulators.
So my research on my engine model had me convinced I had the flywheel with the larger magnets on my 19 hp. I managed to get a hold of an Onan 20a regulator for a good price. I decided to use this regulator incase my amps would be higher than 16 after I rewind this into a monster.
Long story short, I took it apart and found out I actually have small flywheel magnets on both tractors. No big deal, I still have plenty of amps available with my rewind. This made a lot more sense since my tractor does not have an electric PTO, or hydrostatic tranny. There was really no good reason why I would have had the larger magnets to begin with. Couple that with a dual circuit alternator, it really makes no sense.
So with all the B&S information on their alternators, flywheels, and tractor manuals in conjunction with all the other famous alternator/stator rewinding forums and pdf files I've read, I became convinced I can tackle this job.
So here we go; (To prevent confusion, I may call a stator an alternator and an alternator a stator. They're both the same thing, so don't get confused)
Our flywheel has 12 magnets inside it. They simple alternate N, S, N, S, N, S, N, S, N, S, N, S. (That being north aiming inward, then south inward, etc)
Now the dual circuit alternator has 12 poles that match up perfectly against all 12 of those magnets. EXCEPT that 4 of those 12 poles are basically dud poles that are for mounting the stator to the engine.
So we actually have 8 poles we only need to worry about rewinding.
Another thing I noticed: These alternators were NEVER dipped in any additional epoxy or resin for any added protection. They did use an epoxy in several locations to hold certain wires and parts in place, but other than that, you can completely unwind it quite easily.
For the record, the dual circuit stator has one end of the two magnet wires connected together and mounted to the iron frame of the stator core. Each wire then goes it's separate way (on one side) where it meets at the other end and the larger gauge wire is your a/c power for lights and the much smaller gauge wire is your DC charging with the diode.
Since this is split in half from 8, it's 4 poles per side of winding. The small gauge wire does 69 turns on each pole for a grand total of 276 turns. Two poles are wound CW, two other poles CCW.
The large gauge wire does the same thing, except that it has 29 turns per pole for a grand total of 116 turns. Once again, two are wound CW, two other poles are CCW.
For the way would my stator. I basically copied the way the 696458 is wound. It's actually easier than the description above for the dual circuit alternator. At no point do you connect any of the wire to the iron core of the stator. One wire is going to go in, you do all your turns and meet back at the beginning. One wire in, one wire out. This is about as simple as it gets. There's no additional wires. No confusion about delta or Y wiring. No 3 phase. This is just a single phase wind that isn't difficult.
Next thing I noticed was that my 16 gauge, (1.3mm) magnet wire was WAY larger than the wire used on the 10/16amp alternator. Since the engineers designed these to likely charge our systems optimally at around the 3000 rpm range, I decided to try and re-invent the wheel with changing the number of turns to try and miraculously pull more power out of small magnets.
I did run into some minor and large issues with using 16 gauge wire. The minor one is that could NOT fit 29 turns per coil. I believe I averaged about 26-28 per coil (keeping count was actually far more difficult than anticipated). But this lower level of turns didn't seem to negatively effect me in the end.
The large issue was that it made the stator so fat and juicy, that I was literally missing about 1 mm of clearance to the top of the flywheel when I mounted it back down with the giant nut! :tango_face_surprise
At this point, I was either to scrap the whole idea (because my stator was covered in red varnish and essentially put together to NOT be taken apart)
So I started with trying to etch out a groove all around the flywheel to allow the clearance of the magnet wire (this failed as the cast of the flywheel just eats bits). My next option was to lower the mounting bracket of the stator my trimming a hair off. There was plenty of room to do so, and this is what I did and it has worked so far. I would never recommend doing this. If you should attempt winding this yourself, use 18 gauge and nothing larger! Go for 29 per coil
In terms of winding the coils, this is probably the most important bit of information you want to keep track of: The rotation of CW or CCW is extremely important. This stator is particularly unique as you cannot just follow the typical "CW, CCW, CW, CCW" pattern. The reason for this is because of the 4 dud poles I mentioned earlier. When winding the poles, all CW wound poles MUST face either a North or South Magnet. Same situation for the CCW poles.
So basically, when you place the stator in the center of the flywheel, every SECOND magnet must be aligned with a CW pole, and every CCW pole must be aligned with the other magnets.
So when winding this stator, when you start with the first pole you can do the rotation CW, then you skip the second pole (because it is a mounting bracket) and then wind the third pole. This pole must be wound CW so that the magnets are aligned correctly to the right rotation. Once you then move to the wind the next pole beside it, you can switch rotation to CCW... Keep this same pattern going and you'll be fine. Remember: any two poles that are right beside eachother are wound in complete opposite directions. and any two poles on either side of the mounting bracket is wound in the SAME direction.
Pic 1 shows the stator completely stripped down naked. (notice how it's two halves put together). Pic 2 is with the plastic mounting pieces back on.
pic 3/5 is a side by side to a 10/16 amp stator with the size difference! pic 4, 6, 7 is the complete stator before red enamel was added ( used JB weld in specific spots similar to the OEM epox'd areas. Pic 8 is the final result before tossing it in.
With a usual slowdown at work around this time of years, I started tackling this tractor with several fix ups and upgrades. I purchased a very good quality set of LED lights and mounted them after I yanked out the OEM bulbs and OEM reflector and tossed them for a field goal. I also added a 6 way set of strobing emergency lights, installed a 1,000 lbs strap winch for raising and lowering blower, tossed out OEM amp meter and installed an LED voltage/amp digital meter. Also custom mounted a full sized car battery for more CCA and rear weight.
After all this, I investigated into the charging system to see how she works. (B&S actually has lots of very nicely written and well documented information on their equipment in pdf files) I was disappointed to find out I won't yield optimum results with the current setup. The factory tractor is perfectly fine for running wimpy incandescent lights (which are ok for mowing lawn in the dark in summer), and is ok for charging the battery. Basically, I have the world famous dual circuit alternator.
This is basically two halves of two of their other alternators side by side. One side produces a/c power strictly for the lights. Other side produces a/c power as well, but is instantly tossed into a diode to change it to dc current for charging the battery. (This clearly doesn't provide me enough power by the fact my voltage drops to 12.0v when my lights are on). When all lights are off, I'll see a voltage as high as 17 at the higher rpm... The single diode is really not the smartest way we could be charging a battery.
Since Everything I added electrically requires DC power, I'm WAY down on amps, and have half the alternator doing nothing. :tango_face_sad: So looking over B&S' list of alternators, I was able to see I do have options. They have a somewhat expensive regulator that directly plugs into this alternator (with the removal of the exsiting diode) to then make it into a full dc regulated charging system. ( I still found this to be somewhat mickey mouse since we have two different gauge sizes of wire and turns going into the voltage regulator)
So a good chunk of us have a 696459 dual circuit alternator. I was now eyeballing the direct fit 696458 that can produce 10 amps on the flywheel with small magnets (flywheel most of us have). Or 16 amps if we have the flywheel with the larger magnets. Add in the 16 amp voltage regulator and we're good to go.
Now I'm also looking to upgrade my other MTD lawn tractor to LED lights and want to improve its charging system to use a real voltage regulator. Instead of purchasing two 696458 alternators, I decided to tackle rewinding one with some magnet wire I have laying around, and use the heavier gauge wire on one side to transform the other alternator from a 696459 to 696458. Then I just need to purchase some regulators.
So my research on my engine model had me convinced I had the flywheel with the larger magnets on my 19 hp. I managed to get a hold of an Onan 20a regulator for a good price. I decided to use this regulator incase my amps would be higher than 16 after I rewind this into a monster.
Long story short, I took it apart and found out I actually have small flywheel magnets on both tractors. No big deal, I still have plenty of amps available with my rewind. This made a lot more sense since my tractor does not have an electric PTO, or hydrostatic tranny. There was really no good reason why I would have had the larger magnets to begin with. Couple that with a dual circuit alternator, it really makes no sense.
So with all the B&S information on their alternators, flywheels, and tractor manuals in conjunction with all the other famous alternator/stator rewinding forums and pdf files I've read, I became convinced I can tackle this job.
So here we go; (To prevent confusion, I may call a stator an alternator and an alternator a stator. They're both the same thing, so don't get confused)
Our flywheel has 12 magnets inside it. They simple alternate N, S, N, S, N, S, N, S, N, S, N, S. (That being north aiming inward, then south inward, etc)
Now the dual circuit alternator has 12 poles that match up perfectly against all 12 of those magnets. EXCEPT that 4 of those 12 poles are basically dud poles that are for mounting the stator to the engine.
So we actually have 8 poles we only need to worry about rewinding.
Another thing I noticed: These alternators were NEVER dipped in any additional epoxy or resin for any added protection. They did use an epoxy in several locations to hold certain wires and parts in place, but other than that, you can completely unwind it quite easily.
For the record, the dual circuit stator has one end of the two magnet wires connected together and mounted to the iron frame of the stator core. Each wire then goes it's separate way (on one side) where it meets at the other end and the larger gauge wire is your a/c power for lights and the much smaller gauge wire is your DC charging with the diode.
Since this is split in half from 8, it's 4 poles per side of winding. The small gauge wire does 69 turns on each pole for a grand total of 276 turns. Two poles are wound CW, two other poles CCW.
The large gauge wire does the same thing, except that it has 29 turns per pole for a grand total of 116 turns. Once again, two are wound CW, two other poles are CCW.
For the way would my stator. I basically copied the way the 696458 is wound. It's actually easier than the description above for the dual circuit alternator. At no point do you connect any of the wire to the iron core of the stator. One wire is going to go in, you do all your turns and meet back at the beginning. One wire in, one wire out. This is about as simple as it gets. There's no additional wires. No confusion about delta or Y wiring. No 3 phase. This is just a single phase wind that isn't difficult.
Next thing I noticed was that my 16 gauge, (1.3mm) magnet wire was WAY larger than the wire used on the 10/16amp alternator. Since the engineers designed these to likely charge our systems optimally at around the 3000 rpm range, I decided to try and re-invent the wheel with changing the number of turns to try and miraculously pull more power out of small magnets.
I did run into some minor and large issues with using 16 gauge wire. The minor one is that could NOT fit 29 turns per coil. I believe I averaged about 26-28 per coil (keeping count was actually far more difficult than anticipated). But this lower level of turns didn't seem to negatively effect me in the end.
The large issue was that it made the stator so fat and juicy, that I was literally missing about 1 mm of clearance to the top of the flywheel when I mounted it back down with the giant nut! :tango_face_surprise
At this point, I was either to scrap the whole idea (because my stator was covered in red varnish and essentially put together to NOT be taken apart)
So I started with trying to etch out a groove all around the flywheel to allow the clearance of the magnet wire (this failed as the cast of the flywheel just eats bits). My next option was to lower the mounting bracket of the stator my trimming a hair off. There was plenty of room to do so, and this is what I did and it has worked so far. I would never recommend doing this. If you should attempt winding this yourself, use 18 gauge and nothing larger! Go for 29 per coil
In terms of winding the coils, this is probably the most important bit of information you want to keep track of: The rotation of CW or CCW is extremely important. This stator is particularly unique as you cannot just follow the typical "CW, CCW, CW, CCW" pattern. The reason for this is because of the 4 dud poles I mentioned earlier. When winding the poles, all CW wound poles MUST face either a North or South Magnet. Same situation for the CCW poles.
So basically, when you place the stator in the center of the flywheel, every SECOND magnet must be aligned with a CW pole, and every CCW pole must be aligned with the other magnets.
So when winding this stator, when you start with the first pole you can do the rotation CW, then you skip the second pole (because it is a mounting bracket) and then wind the third pole. This pole must be wound CW so that the magnets are aligned correctly to the right rotation. Once you then move to the wind the next pole beside it, you can switch rotation to CCW... Keep this same pattern going and you'll be fine. Remember: any two poles that are right beside eachother are wound in complete opposite directions. and any two poles on either side of the mounting bracket is wound in the SAME direction.
Pic 1 shows the stator completely stripped down naked. (notice how it's two halves put together). Pic 2 is with the plastic mounting pieces back on.
pic 3/5 is a side by side to a 10/16 amp stator with the size difference! pic 4, 6, 7 is the complete stator before red enamel was added ( used JB weld in specific spots similar to the OEM epox'd areas. Pic 8 is the final result before tossing it in.