Converting a lawn tractor

Sleeve Hitch and Winch

2011-08-27T16:29:00.000-07:00

I don't remember exactly when I added it but it was about 6 months ago/end of winter. I bought one of the Harbor Freight 12V winches and hooked up a sleeve hitch I had put together. I dont really have any attachments to put on it other than a hack job cultivator. I used the cultivator at a friends house with no grass in yet. We actually used the cultivator and the plow and the trailer to move 2 tons of gravel and level off his yard after putting sprinklers in.

Old Hat

2010-08-05T12:41:00.001-07:00

I haven't updated for a while because everything is working as needed. I've used the mower nearly every week to mow my yard. Though my front yard is really too small for this machine, so mostly just the back yard. I use the battery push mower I picked up on Craigslist for $25 to do the front yard. The tractor does a great job for me, and cuts well enough. I think I need to sharpen the blade. I'd much rather have 2-3 small blades driven by individual motors, but I haven't found motors for that yet.
I'm still working on a rear implement system. I've abandoned the 3-point hitch and I'm nearly done with a sleeve hitch system. My first implement is a plug aerator because my yard needs it! After that perhaps a plow of some kind to use on my brothers property. I can see a use for a de-thatcher, a drop spreader (maybe broadcast?), perhaps even a sprayer.
I'd really love to get something with more fixed gears rather than the belt drive. I'd also very much love a shunt wound motor for a more constant RPM. Future project I guess!

Snow Plow

2009-12-27T13:01:00.001-08:00

I guess it's been a little while since I updated. I finished the mower deck at the end of summer. I had to build an extension shaft and shaft coupler to mount the pulley which drives the blade. I used it to mow the last month of the season! It doesnt do so well with thick grass. It bogs down the blades and motor until it's not spinning fast enough to cut. But if I keep up on it it works great. I now wish I had a catcher for it, or make it mulch.

Winter showed up and we got some snow. I had built part of the snow plow last year, and having snow inspired me to throw something together. My brother helped me grab some plywood and strap it to the metal ladder under the mower. It worked well enough to plow my driveway, my neighbors drive way, and the sidewalk up and down my street. I would have happily kept plowing, but my brother was bored! I thought it was very clever, but I wanted one not made of wood. I looked through my steel pile and found a 4.5" diameter tube about 30" long. I cut it in half lengthwise and partially flattened it to make a 7" high plow blade. the two half were bolted to some angle iron which is welded to a square tube. the tube pivots on a 5/8" bolt and its angle is held with another bolt. It looks great, but we havent had any more snow for me to use it on! I may need to add some weight to it so it has some hold down force.

I had considered adding the spring system like commercial plows have but it was more complex than I wanted to figure out.

A little test

2009-08-24T10:37:00.000-07:00

I have a bunch of sod I need to pull up and level out. I was thinking I could do it all with a shovel, or I could use this super powerful handy lawn tractor that I have! I have still not made the cutting deck work, but it can pull stuff. I think I can make a sod cutter attachment to pull up my lawn. First I wanted to see if I could produce enough pulling power for that, so I did a little experiment.

I build a little sled from some 3/4" plywood I had sitting around. I loaded it up with the heaviest things I had, a couple buckets of dirt and decorative bricks.

I couldn't move the sled with my own strength, I'm guessing it was about 1000lbs. I pulled it around my yard several times. The tractor slowed down a bit, pulling about 50A in the lowest speed. I was impressed! It lost traction (particularly when trying to turn) and dug up some grass in a few spots. I think I could pull more if I had more weight on the tractor. I think this means I will have plenty of power for cutting sod, or pushing/pulling plows! Now I just need to finish the snow plow attachment, build a sod cutting attachment, and get the cutting deck working.

I'd like to change it somehow to stop the motor faster. When I adjust the belts to where they should be, it grabs when I try to stop, and the momentum of the motor forces the tractor to roll forward another 6". Bad when trying to get close to something and not hit it. Either better brakes, some way to make sure the belt doesnt grab the pulley, or just make the motor stop. Being series wound I think if I add a diode backward across the field and short the armature, if I switch fast enough from on to off it will plug brake itself. Not sure on that yet though.

Mower deck

2009-04-06T12:07:00.001-07:00

I finally got that motor mounted to the 30" deck. However I deem it a fail. It would spin the blade and draw a lot of current (30A). But as soon as the blade hit the grass it slowed or stopped and pulled lots of current (80A)!

So I put the cordless mower back together. Maybe I'll get some batteries and use it as it is. My next plan is to build a pulley shaft to run the blade from the main motor. I suppose I might be able to find a multiblade deck, but I'm not waiting around for that. Besides, I dont have enough motors to run a multiblade deck.

Oh well, not what I wanted but it will get it working!

Making the mower mow

2009-03-24T09:25:00.000-07:00

I posted an ad on craigslist several weeks ago, looking for any cordless 24V mower. The other day I got an email from a guy with a cordless mower that has dead batteries. I bought it for $25. It was a Toro E24, 18" mower.

Inside I found a permanent magnet motor, about 6.25" long, 3.5" diameter. 4 6V gel batteries, a 24V gel charger, and a double throw contactor

The motor might be a bit small for a 30" blade, but I'm going to try it anyway. I think it will work better than the 250W scooter motor I was going to try! It looks like I can even use the original blade mounting bracket with the 30" blade, if I drill a couple of alignment holes in it.
Next is to get it mounted to the deck. Maybe I'll install heavier wires on the motor too. If only I can find a few more of these motors, I can do a multiblade deck :).

Up and running, mostly

2009-03-24T09:03:00.000-07:00

I have recovered the seat with new foam and vinyl. The seat switch is not yet working though.

I got a volt meter and amp meter+shunt from ebay (China). Blue LEDs mean it will work in the cold when LCD freezes up.

Still using a single borrowed battery I've been using the tractor already. Here I have about 550 lbs of brick in the trailer. That sure saved my back!

Here are the new batteries. I bought them at Batteries Plus. Werker brand. I had designed for a 50 amp load, running for an hour. I wanted about 50% DOD. I was looking for at least 120 minute reserve capacity. I ended up getting 160 RC batteries. They are much larger than I need, so they should last quite some time! I plan to build an enclosure around the batteries and motor eventually.

This is the control panel. The original key switch turns on the system (and meters). The red button and switch control the PTO contactor. Flip the switch to on and then press the button to start. Flipping the switch to off, turning the key to off, or breaking the seat switch will all turn off the PTO.

Getting closer

2009-02-25T10:12:00.000-08:00

With the single pulley reduction, I hooked up 36V and took it for a spin. WAY too fast for mowing! I changed to 24V, which gave a perfect speed. So I measured current draw at 24V to help figure out battery size. I needed 30-50A on my yard (straight, turning, slight elevation changes, etc). Too much. I wanted to keep the drive in the 20-30A range.

I thought putting the original variable pulley back in would slow it enough to run on 36V and lower current. After ordering replacement belts and tension springs (which I didnt need, I just misplaced the originals) I put the original system back in.
Advantages: 6 mechanical speeds, original design
Disadvantages: 2 belts, much more complicated system.

But at 36V it was still too fast for mowing, except for in the lowest speed setting available. The highest speed setting was like a go-cart. Fun, but not as useful! So I tried it at 24V. PERFECT speeds! Mowing in the upper speed ranges, extra slow in the lower ranges.

I figured I'd need a little less current maybe. Nope, it still draws 30-50A.

So it looks like I may have little use for the electrical 2 speed I built. I havent tried running it with the series resistor yet, but I'm happy with the speeds at full voltage.

PULLEY
I had to make myself a new pulley for the motor. The belts are 5/8" wide. I dont have the original pulley that was on the engine (it wouldnt come off). I just cast a large cylinder of aluminum and turned it down to a pulley. My motor has a very large shaft (3/4" IIRC), and I cut the pulley to be as small as physically possible while still fitting on the shaft. It seems to get fairly warm when in use. I hope it's not bad, I really dont know.

BATTERIES
So I figure It will take me an hour (probably less) to mow my yard. It takes me about an hour to do it now with my electric push mower. I assumed an average 40A draw for an hour to a 50% DOD. So I need at least an 80Ah battery, or 120 minute Reserve Capacity. I still dont know how I'm going to spin the mower blade though. I bet the drive motor has plenty of power to spin it, I just have to try building an adapter shaft to hook it up.
I'll just have to go visit a few battery places to see what is available. I dont have a lot of room on the mower to mount batteries. I think I can fit a couple of 12V RV or marine batteries behind the seat.

WELDING
I've always wanted to weld at home. I have used oxy-acetylene and MIG before. I looked into stick welding a bit and found it's not as difficult to do as I thought. In fact, the Electrack had a welding attachment that just taps into the batteries. I bought some 1/16" welding rods, goggles, and a torch. Using some old jumper cables I hooked up a pair of 12V batteries and started welding the plow ladder out of EMT conduit. WOW! I was welding at home without a >$200 machine! I was quite excited and surprised, and very happy that I can now do my own welding. when I finish my lawn tractor, I will have a semi-portable DC welder too.

TRAILER
I know, I dont even have the mower fully working and I'm already making accessories? Yup! It was fun and easy to do. I've already used it too! I picked up some 4x8" wheels on sale. I found (dumpster diving) and bought some 1/2" and 3/4" electrical conduit. I bought the axle. Also one sheet of 4x8x1/2" plywood and an 8' 2x4. I based mine on plans available online. I adjusted it slightly to suit what I had, keeping the center of gravity over the axle, but the piviot point behind the CG. I also had to raise it up a little to fit the tires I have, and I wanted it light weight. The metal frame is very light, maybe 10lbs. The box is 40"x31"x12". It seems bigger than I invisioned it. I sized it the same width as the mower, both will fit through a doorway (into my garage). I'm in the process of staining the box and designing the hold down latch. I'm thinking about adding a linear actuator to automate the dump mechanism. Maybe later.

PLOW
I built up a ladder that mounts to a couple of piviot brackets on the rear axle and protrudes under the front wheels. It attaches to the mechanism which raises/lowers the mower deck for vertical lift. Install/remove with just 3 pins. It wont provide downforce, but some weight on the end might work. Now I need to finish the front end of it and figure out some kind of blade.

METERS
I ordered some LED meters from China on ebay. I got LED so they could stand up to outdoor temperatures (cheap LCD wont). I bought 200Vdc and 100Adc 4 digit meters. I dont know where I will put them yet. I'm thinking they will go best at the base of the steering shaft.

A bunch of stuff happened

2009-01-06T09:17:00.000-08:00

It's been a long time. We got a lot of snow, and the snow inspired me to get the mower working. I also had some time off work to burn. I had originally planed to mount the motor by it's foot, but decided that a face mount would be easier and quicker. I drilled and tapped 4 bolt holes in the face bell and instead of waiting to get a steel plate I used some 1/2" plywood with several coats of polyurethane. I put slotted bolt holes in the wood plate to allow some belt adjusting.

The smallest pulley I had was a 2-1/4", but the shaft hole was way too small. No problem, I have a lathe! I opened up the bore and broached a new keyway. There was just barely enough metal left in the pulley to fit it all in there. My mounting doesnt give a lot of belt tension adjustment, so I had to try several belts to get the right size. I think it is still just a bit too loose. If I keep the brake on and let the motor go (even in low range) it will slip the belt. I suppose that is a great safety featrure though.

My original plan was to put 3 switches on the foot pedal so that all the way down (brakes on) will stop everything, part way up (brake just comes off) activates low range, and all the way up activates high range. I couldnt figure out a way to add the extra switches (the mower already had a switch for brakes on). So for now I have a user operated toggle switch to select speed range (well, I have wires intended to go to a toggle switch) and when you let off the brake it goes. I think I'll add just one switch for pedal up and arange it so brake on is stop, no switches is low, and pedal up is high. I need to add some safety interlocks I suppose.

I re-covered the seat with new foam and vinyl. It's quite comfy, but I removed the rusted out person-in-the-seat-switch. I should add another seat switch of some kind for safety. I cut out a section of grey outdoor carpet to put in the foot area. I think it looks great, but others say the black traction sandpaper stuff would be better there. I might change it later. I had the carpet already anyway.

After taking it for a test drive on 36V, I thought it was way too fast for mowing. I set it up for just 24V and in high range it is perfect. I suppose I could change the speed control for paralell/series switching for 12/24V, but that might mess up any extra attached motors (the mower). It seems to me that the motor has plenty of power, and I could probably drive a mower blade from the motor. I didnt want to do it that way though.

I'm planning on finding a couple of 19" discarded mowers somewhere around town. I'd like to cut and hack the two decks together into a single dual blade mulching deck. Then I'll need to add a pair of drive motors. It seems that the ElecTrac used 3/4 HP motors for their mower (but I dont know the blade length). I was thinking I could get a couple of 24V 500W "scooter" motors. They are fairly cheap and spinning a 19" blade shouldnt be too much trouble.

I think I have figured out where I can moung a couple of piviot points for a front plow. I'm still thinking over this issue. The frame/body is not real solid so I cant put a lot of force on the front.

I have some photos, I put them in my photo album here

The chassis

2008-07-24T10:20:00.000-07:00

My brother found an old lawn tractor in an abandoned yard and took it home. The gas tank was missing and it was pretty beat up. If he added a gas tank and a battery, it would run. I suggested that he make it electric just for fun! He started taking it apart without me, by first removing the rear axle/transmission. It's an all-in-wonder unit that has forward, neutral, and reverse. The brake is applied to the high speed side before it gets geared down for the wheels. The tractor has a set of variable diameter pulleys to set the drive speed. We removed all the brackets and pulleys from the underside of the chassis and I've been cleaning them up. The seat needs to be re-covered or replaced. Now that everything is removed it's time to clean and paint to make it look a little better.

The motor

2008-07-24T09:07:00.000-07:00

I found a golf cart motor on Craigslist for $25. The guy gave me the contactor/resistor controller with it too. The motor is a GE 5BC48JB152. 3300RPM, 2HP, 36V, 52A, series wound motor. I was pleasantly surprised that it has a front end bell and bearing, not like all current golf cart motors.
The first thing I did was spin it up on 12V just to make sure it worked. Sure enough it did! Next I opened it up. I wanted to learn about how these motors are built. It seemed quite similar to the large 9" ADC in my Tercell, just smaller. The brushes seemed to be in good shape, but there was a ton of brush dust all over inside the case, it made a big mess of my workbench. I carefully dismantled everything and I had a good excuse to go buy a gear puller set. Now that I think about it, I should have got a bearing puller set instead! But I got the bearings off either way. I decided I should replace the bearings while I have it all apart. One bearing was a little corroded and they didnt spin as freely as I thought they should. Add $40 to the total cost so far.
After cleaning brush dust from between my teeth and everything else, the inside of the motor was starting to look good enough to me. Inspired by Jim Hustead, I wanted to make the outside look fun. First I used electrolysis to clean the rust off of the end bells and I primed everything. After much though (I'm indecisive) I picked green and black for the colors (thats what I had on the shelf).
I'm pleased with the paint job, being my first motor work over. I replaced the nuts on the terminals with shiny brass ones to complete the look. I also polished up the output shaft a bit, it has some corrosion on it. (The photo does not show the new nuts).
Is it overboard? Maybe, but I had some time and wanted the experience.

Getting started

2008-07-24T09:02:00.000-07:00

To catch up to now, this is what has happened:
1-obtained an old golf cart motor.
2-cleaned, painted, and replaced the bearings on the motor.
3-disassembled most of the old tractor.
4-de-rusted and painted the drive pulleys and brackets.
5-cleaned and painted the underside of the tractor.

I'll post individual posts for each significant item later