# OBeers Lawncare: Lawn Mowing EV('s) Thread



## OBeer-WAN-Kenobi (May 28, 2010)

Hi everyone,
I've decided to start a build thread here to chronicle my upcomming lawnmower build. I figured a lawnmower would be a great place to start.

Since this is my first EV I've got a lot of questions about the electricity end of things. I can machine, fabricate, and weld just about anything and have access to all of the equipment I'll need but I'm electrically challenged. I used to do car stereo's but this is a lot more complicated; at least to me.

I'm currently looking at a smaller forklift motor to power a riding lawnmower and plan to use either 36v or 48v depending on the size of the chasis of the free mower I'm getting (I haven't even seen it yet). I'd like to use seperate motors to run the blades to cirvumvent the inefficeincy of v-belts and also to make the deck easily removeable.

I think I basically understand how large a motor to use for the traction but I really don't know what to look for to run the blades. I also realize I'll probably need some sort of friction clutch between the blades and motor incase it hits something. 

My secondary project is to build another mower deck that can be pulled behind or pushed in front of my electric golf cart. I don't have the cart yet, but it should be delivered next month. I'd like to be able to plug the deck right in to the golf cart and use the carts batteries to run it. I plan on putting an ATV winch on the front of the cart and will use that to lower and raise the mower deck (and a plow at a later date).

Anyway, that's enough for the first post. Any comments and help would be greatly appreciated.


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## major (Apr 4, 2008)

OBeer-WAN-Kenobi said:


> My secondary project is to build another mower deck that can be pulled behind or pushed in front of my electric golf cart.


Hi again OBeer,

See post #7, http://www.diyelectriccar.com/forums/showthread.php?t=45125 There is not a separate forum here for electric tractors and/or mowers. But there have been quite a few threads and posts. Do a search on the site.

Regards,

major


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## TX_Dj (Jul 25, 2008)

The way we've done it around here is to use one motor to replace the ICE, and retain the stock blade PTO.

Flip the switch and you can move or mow same as usual. Simple contactor controller with a DC circuit breaker rated at the amperage you want to set as your upper current limit.

This is the same way my electric push mower works, it has a 40A thermal breaker and a simple contactor controller. It came this way from the factory (black & decker).


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## OBeer-WAN-Kenobi (May 28, 2010)

TX_Dj said:


> The way we've done it around here is to use one motor to replace the ICE, and retain the stock blade PTO.
> 
> Flip the switch and you can move or mow same as usual. Simple contactor controller with a DC circuit breaker rated at the amperage you want to set as your upper current limit.
> 
> This is the same way my electric push mower works, it has a 40A thermal breaker and a simple contactor controller. It came this way from the factory (black & decker).


I'm sorry, are you describing what you used to substitute for a controller or what you are using to stop the motor in an overload like running over an oak tree stump?

I did just purchase a small clark forklift for the motor and should be able to use the controller off of it as well as far as I know.


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## OBeer-WAN-Kenobi (May 28, 2010)

Just a little update.
I got the forklift home tonight. The guy I bought it from had a bigger forklift and put in on my trailer for me but when I got it home I had to do it myself. Luckily it's a tilt trailer so I just pulled it off with a chain and my F-250.

The motor appears to be an ADC 6.7" but I haven't taken anything apart yet. Its hotter than the dickens out today so maybe ill rip into it tomorrow morning.

If anything interesting happens ill let you guys know.


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## OBeer-WAN-Kenobi (May 28, 2010)

Another update,

I removed the traction motor and it is a Prestolite MGT. Thanks Major, for your information in the forklift motor thread.

I've also removed the hydraulic motor and this one is also a Prestolite MGT but just slightly smaller than the traction motor.

I'm still hoping for a little more info on these two motors; specifically the RPM and continuous power ratings. I'm having a hard time finding it out for myself. I did find out that Prestolite was bought by another corporation but I couldn't find any specs for these motors on their website.

Anyway, I took one of the motors apart and everything appears to be in good shape besides being dirty. The brushes were seized up a bit but a few gentle taps with the handle of a screwdriver and they loosened up and were sliding up and down like they're supposed to.

I'll be dropping the motors off at a local motor repair shop just to get cleaned and checked out but I don't think I'll need any actual repair done.

Sometime this week I'll try to get all of the electronics out of the forklift before they get rained on too much. I was lucky enough to find a wiring diagram that someone had taped to one of the inside panels of the lift so that's good. Hopefully it will be enough to help me through.

ETA: I still have yet to figure out a good and safe way to keep the motor from over RPM if a belt breaks. If anyone has a good and cheap way of doing it, let me know. Oh, and suggestions for batteries and a charger would be great too. 36 volt system.


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## Woodsmith (Jun 5, 2008)

OBeer-WAN-Kenobi said:


> ETA: I still have yet to figure out a good and safe way to keep the motor from over RPM if a belt breaks. If anyone has a good and cheap way of doing it, let me know.


If you have a chat with Jimdear2 he was mentioning to me a fix he has done using an aftermarket car tachometer with shift light.

I will need to add the same fix, eventually, to my tractor project.


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## major (Apr 4, 2008)

OBeer-WAN-Kenobi said:


> I removed the traction motor and it is a Prestolite MGT. Thanks Major, for your information in the forklift motor thread.
> 
> I've also removed the hydraulic motor and this one is also a Prestolite MGT but just slightly smaller than the traction motor.


Hi OBeer,

The traction and pump motors are both Prestolite MGT type. This means that they both are of the same electromagnetic design. They had different numbers following the MGT, like 4011 and 4012. Those numbers specify the mechanical design. As you can see, one is a traction motor, 4 terminal (reversible) with an external shaft (likely). The pump motor is likely a unidirectional (2 terminal) motor with an internal shaft to mate to the pump. Likely the pump motor isn't going to be of much use to you. Except possibly for spare parts for the traction motor.

I'm not surprised you cannot find specs on the motors. These are not commodity products. They are specifically designed and manufactured for the OEM. I am familiar with them from a previous life. They were also used at 48 volts. When at 36 volts, IIRC, had a continuous rating of about 7 hp, maybe in the range of 2700 RPM. This is if they were ventilated with internal fan. At 48 volts, maybe up to 10 HP at 3600 RPM.* Overload capability is excellent. The brushes are about the same size as you will find in a 9 or 11 inch WarP motor. Should be no problem using controllers at 500A limit, or higher. 

I'd be sure to keep your operational RPM below 5000; 4000 is better. Max tolerable is likely 6000. The pump motor may have had the standard Prestolite 4.5 degree advance for unidirectional motors. The traction motor would be on neutral. You can go higher on voltage but would have to advance it. And watch the RPM.

Good luck with them,

major


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## OBeer-WAN-Kenobi (May 28, 2010)

Thanks again major.
Those ballpark specs should help alot.



major said:


> Hi OBeer,
> 
> The traction and pump motors are both Prestolite MGT type. This means that they both are of the same electromagnetic design. They had different numbers following the MGT, like 4011 and 4012. Those numbers specify the mechanical design. As you can see, one is a traction motor, 4 terminal (reversible) with an external shaft (likely). The pump motor is likely a unidirectional (2 terminal) motor with an internal shaft to mate to the pump. Likely the pump motor isn't going to be of much use to you. Except possibly for spare parts for the traction motor.


Why would the pump motor not be of much use? (Remember the electrical/motor ignorance here....) I was thinking I could use this in another project where it would be powering a mower deck (not a whole tractor) similar to what you posted in another thread and plug in to my electric golf cart. You are correct that it has a female shaft, but that's not much of an issue. I could either use parts from the hydraulic pump to make it a male shaft or just machine something up. If it wouldn't work for some reason I'm not seeing here I could always keep the hydraulics and make a wood splitter or something out of the rest of the forklift pieces...LOL.

Does 2 terminal mean it should have 2 poles? The smaller motor has 4 poles and 8 brushes as well. I'm not at home now or I'd check the number of terminals as I've forgotten.


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## major (Apr 4, 2008)

OBeer-WAN-Kenobi said:


> Why would the pump motor not be of much use? (Remember the electrical/motor ignorance here....) I was thinking I could use this in another project where it would be powering a mower deck (not a whole tractor) similar to what you posted in another thread and plug in to my electric golf cart. You are correct that it has a female shaft, but that's not much of an issue. I could either use parts from the hydraulic pump to make it a male shaft or just machine something up. If it wouldn't work for some reason I'm not seeing here I could always keep the hydraulics and make a wood splitter or something out of the rest of the forklift pieces...LOL.
> 
> Does 2 terminal mean it should have 2 poles? The smaller motor has 4 poles and 8 brushes as well. I'm not at home now or I'd check the number of terminals as I've forgotten.


I was speaking mainly about the shaft on the pump motor. Internal splines or tang drives are unusable for most guys. However, if you can figure it out or use it with the pump, more power to you 

Both the MGT motors are basically the same size, 7.2 inch diameter with 5 inch cores and 2 inch comms. One may look larger due to the flange or something. They are both 4 pole (magnetic poles) motors. For wound field DC motors, 4 terminals are required for reversible motors (traction) but only 2 terminals for unidirectional motors (pump motors).


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## OBeer-WAN-Kenobi (May 28, 2010)

Thanks major, I understand now. Yeah, Machining/Fab no problem. Electricity=uhmmmm..... LOL



Woodsmith said:


> If you have a chat with Jimdear2 he was mentioning to me a fix he has done using an aftermarket car tachometer with shift light.
> 
> I will need to add the same fix, eventually, to my tractor project.


That sounds like a good idea to me and fairly inexpensive too. You could take out the shift light and rig it to a relay to throw out a contactor or something right?

I'll PM Jimdear2 and see what he has to say. Thanks!


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## OBeer-WAN-Kenobi (May 28, 2010)

Brought my motors down to the local motor guy to get cleaned up and checked out. When talking to him on the phone he was worried about running them continuously but after seeing them, and calling them monsters, he wasn't too worried about powering a paultry lawn mower. 

Probably going to pick up the donor tractor tonight or tomorrow night. I've got to swipe a trailer from one of my friends.

I've started thinking about batteries now. Any suggestions for reasonably priced....er...cheap batteries that will do the trick? I'm still planning on 36 volts and conservatively, I'm guessing the thing will probably draw about 50amps continuous (with the deck engaged). It will probably be a little less but I'm not so good with the calculations. My target is to mow for at least 1 hour before hitting 50% DOD. 

If someone would help me out with the calcs and make sure I'm not off too much here that would be great! 

Thanks again!


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## TX_Dj (Jul 25, 2008)

OBeer-WAN-Kenobi said:


> I'm sorry, are you describing what you used to substitute for a controller or what you are using to stop the motor in an overload like running over an oak tree stump?
> 
> I did just purchase a small clark forklift for the motor and should be able to use the controller off of it as well as far as I know.


My point is there's really not a reason for a controller in this application. The transmission sets the speed the mower moves at, so all you really need is a "big on/off switch" to turn the motor on and off.

That's what we've done in the past, and what I've seen in lots of other mower conversions.


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## Woodsmith (Jun 5, 2008)

OBeer-WAN-Kenobi said:


> I've started thinking about batteries now. Any suggestions for reasonably priced....er...cheap batteries that will do the trick?
> Thanks again!


I got my batteries for my tractor gifted to me from Simon Rafferty on the forum.

He went to a local scrap yard and tested all their Optima red tops. He bought them for £3 each with a sell back of £2 each. I reckon £1 per battery is pretty good.

That may be a way to go, at least initially, to get things moving and tested before you decide what to invest more money in if you find it necessary.


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## OBeer-WAN-Kenobi (May 28, 2010)

Woodsmith said:


> I got my batteries for my tractor gifted to me from Simon Rafferty on the forum.
> 
> He went to a local scrap yard and tested all their Optima red tops. He bought them for £3 each with a sell back of £2 each. I reckon £1 per battery is pretty good.
> 
> That may be a way to go, at least initially, to get things moving and tested before you decide what to invest more money in if you find it necessary.


That sounds like pretty good advice to me and the way I'd like to go to start off. That is if I can find a scrapyard around here that has old batterys they're willing to part with. But I don't know where to find some £. I only have $, so I might be screwed.... 

Seriously, though, what's the best way to test batteries that I may find? Is there a prefered method/Tester? Been doing a lot of reading here but still pretty ignorant on quite a few electrical matters.

I'd also like to get everyones thoughts on which new FLA batteries would offer me the best bang for the buck in my application. That way I've got something lined up for later. I'm still entertaining 6v and 12v options, though the 6v would depend a lot on the footprint of the battery.

Thanks again!

ETA: got the tractor home tonight but didn't have a trailer. Something kind of funny about a manufacturing engineer and a mechanical engineer loading a lawn tractor into the back of a truck with nothing but a rachet strap and no ramps...... let the engineer jokes fly!


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## Woodsmith (Jun 5, 2008)

OBeer-WAN-Kenobi said:


> That sounds like pretty good advice to me and the way I'd like to go to start off. That is if I can find a scrapyard around here that has old batterys they're willing to part with. But I don't know where to find some £. I only have $, so I might be screwed....
> 
> Seriously, though, what's the best way to test batteries that I may find? Is there a prefered method/Tester? Been doing a lot of reading here but still pretty ignorant on quite a few electrical matters.
> 
> ...


Where there is a will, there is a way.
I have loaded using all manner of bits of equipment, it is part of the fun.

Batteries can be tested with a battery load tester that places a large load on the battery and shows the sag.
It is a quick way of testing a fully charged starting battery. The breaker may have one of their own so worth checking before buying/borrowing one.

At the breakers you would want to look for sealed batteries that have come out of crashed or damaged cars. More chance of the battery being good when the car went to be broken.
Unsealed ones may have lost some electrolite in transit and ones from rusted out old wrecks may not have been looked after and may be the failing part that lead the car to be broken.

To many breakers the batteries are only worth the lead recycling cost as they can not really sell them on as usable.

Ultimately, you test all the best looking ones and then make an offer for the ones that seem to have a good reading.

I'd recommend negotiating the price in $ as the exchange rate to £ wouldn't be cost effective.


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## OBeer-WAN-Kenobi (May 28, 2010)

Thanks woodsmith.... but does that mean that I'd have to charge these batteries first before testing them? That would take a while.....


Another small update. The donor forklift has an EV-100 control in it and had a handy wiring diagram taped inside one of the panels. I searched this forum and am still having a hard time getting more info on this control though I did find a thread where it was mentioned, that thread was mostly for the EV-1 control. Any of you guys got some good info?


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## sjc (Oct 28, 2008)

TX_Dj said:


> My point is there's really not a reason for a controller in this application. The transmission sets the speed the mower moves at, so all you really need is a "big on/off switch" to turn the motor on and off.
> 
> That's what we've done in the past, and what I've seen in lots of other mower conversions.


I'm not arguing with you, since you've done it and it works, but I have a question: what load is there on the motor when the switch is on but the transmission is in neutral? I'm concerned about overspeed if the motor has full current but no load.


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## Woodsmith (Jun 5, 2008)

OBeer-WAN-Kenobi said:


> Thanks woodsmith.... but does that mean that I'd have to charge these batteries first before testing them? That would take a while.....


No need. If the battery is dead or low at the breakers then assume it has been left discharged for too long and ignore it. 
Only bother with the ones that are still holding the full, or nearly full, charge that they came in with.


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## OBeer-WAN-Kenobi (May 28, 2010)

Woodsmith said:


> No need. If the battery is dead or low at the breakers then assume it has been left discharged for too long and ignore it.
> Only bother with the ones that are still holding the full, or nearly full, charge that they came in with.


Cool. Thanks!

Another update. I've finished taking off the ICE, electrics and some body panels that were in my way on the mower.

I'm really thinking about using the hydraulic motor from the forklift now instead of the traction motor. This lawnmower has a transmission so it's kind of a waste to put a bidirectional motor on it. I'll keep thinking about it. Both the hydraulic and the traction motor appear to be the same size so that shouldn't figure into it at least.

I've attached some pictures for once, hopefully they come out ok. All I've got right now is my cell camera.

P.S. Don't mind the dog, he's a ham....


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## OBeer-WAN-Kenobi (May 28, 2010)

Hi guys,
I haven't been able to get to a salvage yard to look for batteries yet but I did check out my local Farm and Fleet and Walmart and found a few that don't look too bad. I was hoping to get your thoughts...

At Farm and Fleet I found:
27 M 600 CCA 160 RC 120 AH
29 HMDC 675 CCA 210 RC 125 AH

At Walmart I found:
MAXX-29 875 675 125 AH

The walmart one is some sort of hybrid marine battery (or so it says) but I was thinking that AH are the barometer of a deep cycle. Is this true or is it a bad battery to consider?

Thanks again!


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## OBeer-WAN-Kenobi (May 28, 2010)

More updates for you; if anyone's watching that is.

Here are some pix of the motors, pully's and such after I got the motors back from the motor guys place.

The external splined shaft of the 4 terminal motor doesn't have a bearing on one side. So I'm thinking I can take the seal out of the endplate, machine a groove for a retaining ring and basically replace the seal with a bearing.

I'm still thinking about using the 2 terminal motor instead. I can certainly adapt it to work.

Dilemas dilemas


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## major (Apr 4, 2008)

OBeer-WAN-Kenobi said:


> The external splined shaft of the 4 terminal motor doesn't have a bearing on one side. So I'm thinking I can take the seal out of the endplate, machine a groove for a retaining ring and basically replace the seal with a bearing.
> 
> I'm still thinking about using the 2 terminal motor instead. I can certainly adapt it to work.


Hi Beer,

Using the pump motor (with internal spline) would require a pulley shaft with bearings aligned concentric with the motor shaft. Can be done, but a pain in the a$$.

Putting a bearing in the Drive End Head (DEH) of the traction motor ain't the easiest thing either. But if you can mount your belt pulley to the external shaft, makes for a cleaner installation.

Installing a DE bearing requires a shaft journal with a mean tight fit to the inner race. Usually a ground surface, of course concentric to the centers within 0.001 or 2. Then a pressed on bearing. Bearing needs 2 seals, hi temp with hi temp grease.

The DEH must be bored to provide a mean loose fit to the bearing outer race. Bore concentric to the frame pilot within 0.001 or 2 and also square to the centerline. Not hard to do on the lathe. 

The shaft is likely held in position via the located bearing at the Comm End (CE). This means that the DE bearing must be able to float axially to allow for thermal elongation of the shaft. Therefore the pocket for the bearing in the DEH must include space for a thrust washer to press against the outer race of the DE bearing to prevent it from rotation, or else it will wear the aluminum housing and fail.

Good luck,

major


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## OBeer-WAN-Kenobi (May 28, 2010)

I think we are on the same page major. This is what I worked up really quickly. The bearing would be pressed onto the shaft (it's already a nice 1" ground diameter at that point). A slip fit on the od of the bearing, retained by a spring washer, a washer, and a retaining ring.

ETA: Double sealed bearing.........

Later I'll post a work-up for the other motor.


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## OBeer-WAN-Kenobi (May 28, 2010)

Here's some pix of the controller and schematics for any of those that would like to enlighten me on it. This is just one control and some contactors right? I know that some of the lifts use a seperate simpler control for the hydraulics and was kinda hoping I had one of those to use instead of just using contactors..... I know a guy around here that makes electric carts for drunk driving simulations, maybe I'll stop by and have a chat.


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## OBeer-WAN-Kenobi (May 28, 2010)

OK,
Here's my pump motor conversion idea. The only thing I think I'll have a hard time with is finding the actual specification of the spline. Might have to do some trial and error fitting. None of you guys happen to have the specs for a 9 tooth 5/8" diameter spline do you? My machinery's handbook only has 10 tooth and up.

ETA: The part near the top of the pictures is the actual motor endplate.... I just mocked it up instead of putting the internal splines and bearing in it. There is a nice 3.250 diameter counterbore on the endplate that was used to line up the hydraulic pump. I'm using the same c-bore to make sure everything is coaxial.


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## major (Apr 4, 2008)

OBeer-WAN-Kenobi said:


> OK,
> Here's my pump motor conversion idea. The only thing I think I'll have a hard time with is finding the actual specification of the spline. Might have to do some trial and error fitting. None of you guys happen to have the specs for a 9 tooth 5/8" diameter spline do you? My machinery's handbook only has 10 tooth and up.
> 
> ETA: The part near the top of the pictures is the actual motor endplate.... I just mocked it up instead of putting the internal splines and bearing in it. There is a nice 3.250 diameter counterbore on the endplate that was used to line up the hydraulic pump. I'm using the same c-bore to make sure everything is coaxial.


Hi Beer,

What you end up with is 3 bearings on a shaft, which is trouble 99.99% of the time. If you're perfect it can work.

And the 9 tooth spline is an SAE standard, involute, 16/32 DP, 30° pressure angle, ####- sorry, my memory ain't that good for the maj, min dia and such. Should find it in the SAE handbook. Maybe somewhere on line. Or axle fab shop may have hobb or cutter for it.

And does the pump motor rotate the correct direction for you? You cannot reverse it without internal mods.

major


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## OBeer-WAN-Kenobi (May 28, 2010)

major said:


> Hi Beer,
> 
> What you end up with is 3 bearings on a shaft, which is trouble 99.99% of the time. If you're perfect it can work.
> 
> ...


Ah, but it won't be 3 bearings on a shaft. It's really 2 seperate shafts since there will be enough clearance in the spline fit and some clearance in the counterbore. There's really no difference between this and the insides of the pump with a 3rd bearing that was attached to it originally except maybe that its more forgiving since its ultimately attached to pullys and belts.

Thanks for the info on the spline! I'll see if I can find some SAE literature I don't have to buy somewhere. I have access to a lot of ANSI, ISO, ASTM, and ASME stuff but I hardly have anything at all from SAE. It figures its SAE, who else would spec a spline with an odd number of teeth so that its so hard to measure. LOL

I don't know about the rotation yet but I'll grab a 12v battery this weekend and see which way it spins. I imagine the ICE is CW, but I'll check that too. Worst case, I could twist the v-belt to reverse it but I'm not sure that's a good idea....


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## Jimdear2 (Oct 12, 2008)

OBeers Lawncare,

On the subject of motor runaway stopper. refer to this thread 

http://www.diyelectriccar.com/forums/showthread.php?t=30249&highlight=jimdear2

This should answer quite a few of your questtions and I can answer specific questions as well. You don't need a tach. Any suritable rpm switch that can be set to a specific rpm and will trip the relay you use will do. Nitrous oxide switches come to mind.

Sorry to be so long in answering. I have COPD and emphisemia and allergies. I am not getting around too well with the high humidity in this area.

This is a prety crude setup but it does work. Some of the electrical wizards on the site might work up something better.

Jim


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## OBeer-WAN-Kenobi (May 28, 2010)

Thanks Jim!
I posted in the thread you linked to.

For my update today, I grabbed a 12v battery and tested both my hydraulic pump motor and the old ICE that came off the mower. The good news is that. They both rotate in the same direction, CW when viewed from the top. The slightly worse news is that has pretty much cemented my decision to use the pump motor instead of the traction motor to run my lawn mower and that means no tail shaft. So, I may have a bit harder time with the runaway motor prevention. I'll just have to do something on the pully end. It shouldn't be too big of a deal, just bad that its under the mower where more dirt will get to it. Ah well...... to the drawing board!.....errrr...CAD software I mean.


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## OBeer-WAN-Kenobi (May 28, 2010)

Small update for everyone:

I took the mower deck off last night and tried to remove the blades. No worry about sharp edges there....about as sharp as a pry bar. It definitely needs new bearings and at least one new blade adaptor. Other than that, all the sheet metal, mounts, and the shute are in good shape.

I'm trying to figure out how the deck disengages and reengages from power when it is raised and lowered. Maybe the belt just comes on and off the pully? I didn't spend a lot of time attempting to figure it out yet.


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## TX_Dj (Jul 25, 2008)

Yes, typically on the engage lever (if a separate one is included) or on the deck height lever (more typical) there is a setup which tightens an idler pulley which goes to a second belt which drives the deck that comes off a second pulley from the crankshaft of the ICE.

This is the primary reason I suggested one motor to drive them all, KISS principle. Your method with two motors will likely be more efficient overall, if you use a motor controller to drive the transaxle, then you can set your speed with a "throttle" lever/pedal, but if it has a hydrostatic transmission, that wouldn't be entirely necessary, especially if most of the run-time is with the blades down. Select the gear that give you the forward speed desired for mowing, flip the motor on with a contactor and drop the deck to engage.


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## OBeer-WAN-Kenobi (May 28, 2010)

TX_Dj said:


> Yes, typically on the engage lever (if a separate one is included) or on the deck height lever (more typical) there is a setup which tightens an idler pulley which goes to a second belt which drives the deck that comes off a second pulley from the crankshaft of the ICE.
> 
> This is the primary reason I suggested one motor to drive them all, KISS principle. Your method with two motors will likely be more efficient overall, if you use a motor controller to drive the transaxle, then you can set your speed with a "throttle" lever/pedal, but if it has a hydrostatic transmission, that wouldn't be entirely necessary, especially if most of the run-time is with the blades down. Select the gear that give you the forward speed desired for mowing, flip the motor on with a contactor and drop the deck to engage.


I did decide to use the KISS principle, at least initially and go with one motor. My single biggest hangup is safety if the belt breaks. Now that I've decided to use the motor with no tailshaft that becomes a bit harder. Especially if it were to strip out the splines or break my adapter shaft as I'd have no way of sensing it then. Maybe I should just construct a big blast shield around the thing and forget about it. 



The mower itself is an MTD Ranch King (12hp version). I saw one that started out just like it in the EV album when I was looking through that the other day but I don't think the guy bothered to get the deck working.

It's indeed the type that engages by lowering the deck, not with a seperate lever.


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## TX_Dj (Jul 25, 2008)

HAH! The HMGT! I was a very regular member on EVDL at the time John was building that tractor.

Yeah, if yours is the drop-engage type, it should be pretty easy, and if your pulley sizes are the same on the e-motor shaft, you should have no problems getting the idler tension just right.

Cool to see the project coming along!


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## Jimdear2 (Oct 12, 2008)

OBeer-WAN-Kenobi said:


> My single biggest hangup is safety if the belt breaks. Now that I've decided to use the motor with no tailshaft that becomes a bit harder. Especially if it were to strip out the splines or break my adapter shaft as I'd have no way of sensing it then.


 
OBeer,

Don't give up so easily. I can see a couple of easy ways to give over rev protection. bear with me if I cover areas that you have already considered.

Do you plan to keep and use the current belt slackening clutch on the traction drive (not a good idea) or are you going to run a constantly tight belt (recommended) and control slow down and stop with the throttle. If you plan on keeping the clutch you are going to have to have some form of motor cut off or power down to keep from over speeding the motor every time you push in the clutch pedal without first slowing or shuting off the motor. Don't forget that the brake is on the same pedal on most of these MTD tractors.

First Idea:
A spring loaded micro switch that uses a roller 
http://www.mcmaster.com/#snap-acting-switches/=7jsnw0
to bear against a part of the belt that routes through a pully, tensioner or guide so that when a belt is missing it opens the circuit that runs the main contactor. The problem with this setup is it won't account for a worn and slipping belt unless the stroke was short and the adjustment was spot on and it would need protection so that a broken belt can't whip around and distroy it.

Second Idea:
There is usually a space between the drive pulley and the frame where you could mount a proximity switch. 
http://www.mcmaster.com/#proximity-switches/=7jsn1m
You would then drill 1/4 inch holes 180 degreed apart in the drive pully in the area where it is flat and put a 1/4 20 allen head bolt and nuts to make a post sticking up. You then make a bracket that allows you to place the prox switch so that it can sense the bolt heads as they go pass. This will give you 2 pulses per each revolution of the motor. This is the signal used for automotive 4 cylinder aftermarket tach and rpm switches. For your application I would get a rpm switch that triggers a Nox event. This switch is usually a set and forget switch. This switch is used to trigger a latching relay 
http://www.mcmaster.com/#electrical-relays/=7jsru4
or you can use the sealing circuit on a standard dpdt relay that controls the main contactor that is shown in the wiring diagram I posted earlier.

The first idea would pobably be the least expensive and with a good bearing in the roller and a quality switch probably quite durable.

The links I've included are to McMasters/Carr they are for examples with some details of operation for the various components that might help you make your decisions.

If you decide to go with a centrifical switch, I'll be watching with interest as that mighrt just be the KISS way to go.

Jim


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## OBeer-WAN-Kenobi (May 28, 2010)

Hi Jim,
I'm definitely not giving up but this particular problem sure is frustrating. I've even considered seeing if I could horse trade for a compound wound motor but after seeing a few other peoples motors, they're no where near as nice and beefy as my prestolites.

If I can can bore a hole in the tail end plate on my pump motor and drill and tap the shaft I can make myself a "tailshaft" to use just for sensing purposes. Is there any reason I can't do this (the machining)? It won't screw up the motor will it?

The reason I'm stuck on this is that there is a possibility that I could either strip the spline or break my adaptor shaft (see 3d model in previous post) in which case I'd be screwed if I wasn't sensing or switching on the motor shaft itself

I still want to try the centrifugal switch first but I really like your second idea. I'm familiar with the sensors you talk about as we use them at work all the time but I'm having trouble trying to figure out a way to interface with them. Are you talking about an NOs window switch? If so, those are pretty expensive right?

In fact, today I was thinking about interfacing a prox switch with a microcontroller. I'm pretty sure microcontrollers can be found pretty cheap. I've programmed some PLC's before and if I can get a microcontroller with anything like the timer function that the PLC's come with I should be able to make it count pulses per minute (RPM) from the prox switch.... right? The bonus with the microcontroller is that I could interface all the other safety's with it as well, making it a single point of contention. Turn the key on, the micro controller checks and says yea or nea and if it doesn't work itself, nothing happens. Turn the motor on, it checks RPM, get off the seat, it shuts everything down. Break something, it shuts everything down.

The microcontroller idea might be more complex than I think though.

As for the clutch on the mower. I realize it's a problem but I haven't exactly thought about how to get around that yet. There is the neutral position on the transmission to get around as well. A compound wound motor is looking better all the time. I was even eyeing up flipping the rear transaxle 90 degrees and mounting a motor straight to it, then running with my original idea of seperate blade motors. That STILL doesn't get around the transmission neutral problem though.

Maybe I could use hydraulic pump from the forklift and make some sort of hydrostatic system.... It's pretty bad when that actually sounds simpler.

As always, I appreciate all the help!


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## OBeer-WAN-Kenobi (May 28, 2010)

Would this work with the prox sensor? The price is right!
http://www.summitracing.com/parts/SUM-830452/Application/?prefilter=1


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## Jimdear2 (Oct 12, 2008)

OBeer-WAN-Kenobi said:


> Hi Jim,
> I'm definitely not giving up but this particular problem sure is frustrating. I've even considered seeing if I could horse trade for a compound wound motor but after seeing a few other peoples motors, they're no where near as nice and beefy as my prestolites.


Don't blame you I have a Prestolite in my Cub Cadet conversion.



OBeer-WAN-Kenobi said:


> If I can can bore a hole in the tail end plate on my pump motor and drill and tap the shaft I can make myself a "tailshaft" to use just for sensing purposes. Is there any reason I can't do this (the machining)? It won't screw up the motor will it?


No reason not to, That is exactly the way my Prestolite is. I just used a spacer between the reluctor and the end of the motor to get the reluctor out away from the BE cap.



OBeer-WAN-Kenobi said:


> The reason I'm stuck on this is that there is a possibility that I could either strip the spline or break my adaptor shaft (see 3d model in previous post) in which case I'd be screwed if I wasn't sensing or switching on the motor shaft itself


Striping the spline or breaking the adapter is not too likely, for example my Prestolite has a tiny 5/8 inch output shaft and I use it in tractor pulling moving a 5 ton weight transfer sled.



OBeer-WAN-Kenobi said:


> I still want to try the centrifugal switch first but I really like your second idea. I'm familiar with the sensors you talk about as we use them at work all the time but I'm having trouble trying to figure out a way to interface with them. Are you talking about an NOs window switch? If so, those are pretty expensive right?


NOS or NOX = Nitrious Oxide, Race cars don't usually run NOX right off the line, instead they use a rpm sensor switch that turns on the NOX when a specified RPM is reached. Keeps from breaking things. 

If you shop you should be able to get a setable rpm switch for 30 to 40.00 dollars used. The way you would use it is the signal wire from the prox sensor goes to the rpm switch, then when a specified rpm is reached it trigers comntactor control relay, This relay has NO (Normally Open) and NC (Normally Closed) contacts inside. in the normal run position the relay is not activated and current for the main contactor runs through the NC contacts. When the RPM switch is triggered is sends a pulse signal to activate the relay, this opens the NC contacts and breaks the circuit that operated the main contactor.Once the relay is activated the NO contacts are closed current flows to the relay operating coil and holds (seals) the relay in the activated position until power to the relay is removed 



OBeer-WAN-Kenobi said:


> In fact, today I was thinking about interfacing a prox switch with a microcontroller. I'm pretty sure microcontrollers can be found pretty cheap. I've programmed some PLC's before and if I can get a microcontroller with anything like the timer function that the PLC's come with I should be able to make it count pulses per minute (RPM) from the prox switch.... right? The bonus with the microcontroller is that I could interface all the other safety's with it as well, making it a single point of contention. Turn the key on, the micro controller checks and says yea or nea and if it doesn't work itself, nothing happens. Turn the motor on, it checks RPM, get off the seat, it shuts everything down. Break something, it shuts everything down.


The microcontroller idea might be more complex than I think though.[/quote]

If you get the programming right that is a super idea.



OBeer-WAN-Kenobi said:


> As for the clutch on the mower. I realize it's a problem but I haven't exactly thought about how to get around that yet. There is the neutral position on the transmission to get around as well. A compound wound motor is looking better all the time. I was even eyeing up flipping the rear transaxle 90 degrees and mounting a motor straight to it, then running with my original idea of seperate blade motors. That STILL doesn't get around the transmission neutral problem though.


I wouuld run a belt drive directly to the trans from the motor with no belt slack clutch. Then the clutch/brake pedal becomes just a brake pedal. Then you can control motor speed (and ground speed) with the throttle control either pedal or hand throttle (with a little effort you can have both). You will find that you will never need to change gears because of the torque available fro 0 rpm. You will probably use top gear for driveing around and maybe one gear lower for mowing and pulling heavy loads. You want the motor spinning at about 3000 or so rpm while cutting.

I have towed a string 5 hot rod tractors from the pits to the line at a pull with my Cub in top gear with no problem (and I think my Prestolite is smaller then yours). When I use it around the farm I just leave it in third gear. If I stomp on the pedal even in top gear it will pick the front end up. The only time I use the shifter is to go into reverse so neutral is not a problem.

Beleive me, go direct belt to the transmission (replace the clutch linkage with a big spring) and you will find it a pleasure to drive. 



OBeer-WAN-Kenobi said:


> Maybe I could use hydraulic pump from the forklift and make some sort of hydrostatic system.... It's pretty bad when that actually sounds simpler.
> 
> As always, I appreciate all the help!


A bad idea as far as I am concerned too unKISSable


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## Jimdear2 (Oct 12, 2008)

OBeer-WAN-Kenobi said:


> Would this work with the prox sensor? The price is right!
> http://www.summitracing.com/parts/SUM-830452/Application/?prefilter=1


OBeer,

This would work or these.

http://www.summitracing.com/parts/SUM-830450/

or this 

http://www.summitracing.com/parts/SUM-830449-1/

Jim


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## OBeer-WAN-Kenobi (May 28, 2010)

Thanks again Jim, I REALLY appreciate the help.

My question about how to interfacee with the prox sensor..... I meant how does the window switch read the signal from the sensor. Do you need a sensor that outputs a specific signal?

I think I'd like to go ahead and order one of those window switches you linked to. I still may try the centrifugal switch but I think I like this solution better. Could always do both for redundancy.

I like bypassing the clutch but are you using a motor contoller because I haven't exactly planned on that, not that its out of the question. I haven't figurrd out how I'm going to do a throttle without one yet though.


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## Jimdear2 (Oct 12, 2008)

OBeer-WAN-Kenobi said:


> Thanks again Jim, I REALLY appreciate the help.
> 
> My question about how to interfacee with the prox sensor..... I meant how does the window switch read the signal from the sensor. Do you need a sensor that outputs a specific signal?


The prox sensor will put out a pulse each time the reluctor goes by it. So if you want two pulses per motor revolution (this mimics a four cylinder engine tach signal) you would have a two pole reluctor. For a reluctor I used a piece of steel flat stock 1/2 inch wide by 1/8 inch thick with a hole drilled exactly in the center. This then is bolted to the tail shaft and the prox sensor is mounted so it can be adjusted to get the best pulse each time the reluctor passes by. 



OBeer-WAN-Kenobi said:


> I think I'd like to go ahead and order one of those window switches you linked to. I still may try the centrifugal switch but I think I like this solution better. Could always do both for redundancy.


Be sure that the switch you order will work on a four cylinder engine. If it only will work on a V8 then you will need to make a 4 pole reluctor.



OBeer-WAN-Kenobi said:


> I like bypassing the clutch but are you using a motor contoller because I haven't exactly planned on that, not that its out of the question. I haven't figurrd out how I'm going to do a throttle without one yet though.


Yes I'm using a controller, in fact an Alltrax. I think you will like your tractor a LOT MORE if you get a controller. It simplifies many things and makes the tractor much more versitile. If you shop you should be able to find a controller reasonably priced. I personally like Alltrax but there are many good ones out there. Since you are new to this and since there are a lot of bad controllers out there ask on the controller forum before you buy.


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## OBeer-WAN-Kenobi (May 28, 2010)

Jimdear2 said:


> The prox sensor will put out a pulse each time the reluctor goes by it. So if you want two pulses per motor revolution (this mimics a four cylinder engine tach signal) you would have a two pole reluctor. For a reluctor I used a piece of steel flat stock 1/2 inch wide by 1/8 inch thick with a hole drilled exactly in the center. This then is bolted to the tail shaft and the prox sensor is mounted so it can be adjusted to get the best pulse each time the reluctor passes by.
> 
> 
> 
> Be sure that the switch you order will work on a four cylinder engine. If it only will work on a V8 then you will need to make a 4 pole reluctor.


Thanks, that's what I was looking for. Now I understand how it works. So it doesn't matter as long as I can make a piece with the right number of protrusions for the sensor to sense.




Jimdear2 said:


> Yes I'm using a controller, in fact an Alltrax. I think you will like your tractor a LOT MORE if you get a controller. It simplifies many things and makes the tractor much more versitile. If you shop you should be able to find a controller reasonably priced. I personally like Alltrax but there are many good ones out there. Since you are new to this and since there are a lot of bad controllers out there ask on the controller forum before you buy.


I have the EV-100 that came out of the lift that I could use if necessary. I just have to get someone who can identify which EV-100 it is so I know which manual and schematic to use. I have that question posted in the controllers section of the forum. I figured since I'm useing the same voltage as the lift, there's no reason the controller shouldn't work if I decide to use it right?

I kinda wanted to save the controller for a different build with my other motor, which is 4 terminal, bi-directional.

I was hoping I could use a large rheostat or something instead for the throttle on the mower. Is that a bad idea?

Thanks again!


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## mdane (Jun 23, 2010)

Hey OBeers:

We just got an EV-100 and GE motor running in an old bug. We have the manual with schematics. If you post (or repost) the info on your controller, I could try to identify it and get you some documentation.

Mark


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## OBeer-WAN-Kenobi (May 28, 2010)

mdane said:


> Hey OBeers:
> 
> We just got an EV-100 and GE motor running in an old bug. We have the manual with schematics. If you post (or repost) the info on your controller, I could try to identify it and get you some documentation.
> 
> Mark


Thanks Mark,
I'd really appreciate it. If you go back to page #3 in this thread you should see the controller information. I think I have the manuals, but I don't know which one to use because I don't know which EV-100 controller I have. If you could identify it that would be great and then I'll know for sure if I have the right manual and schematics.


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## mdane (Jun 23, 2010)

I think the key information is the letter suffix on the model number on the "brains" part of the controller..... On ours, it's on the black plastic near the tb's 1-6. They'd be in the upper left part of picture one.

Our manual has schematics and descriptions of several models in case yours
s doesn't match up.

FYI We have the "R" version. This has 5 contactors vs. your 4. I know the linked contactors are forward and reverse. I suspect the other two are the 1A over-ride contactor and field weakening (but it could be for regen braking)....

Mark


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## OBeer-WAN-Kenobi (May 28, 2010)

Update:
Received my Summit Racing Nitrous window switch in the mail yesterday and have swiped a prox sensor that was laying around so I'll be able to test the runaway prevention soon. I'm thinking about just hooking it up on a drill or something to get the idea down.



mdane said:


> I think the key information is the letter suffix on the model number on the "brains" part of the controller..... On ours, it's on the black plastic near the tb's 1-6. They'd be in the upper left part of picture one.
> Mark


I haven't had a moment to look at the letter suffix on the controller yet but should get to that this weekend.


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## OBeer-WAN-Kenobi (May 28, 2010)

I know it's been a while but I've been busy with other stuff. Anyway, thought I'd update you all that I found an easy way to convert my pump motor to a keyed shaft!

I got to looking at it the other day and noticed that there was a cross pin going through the internally splined shaft. I thought to myself that it must be the way that they manufactured it. I guessed that they made the internal splined part seperately, for ease of manufacture, and then pinned it to the main shaft. So, I set to taking it apart.

I first removed the endplate and bearing together but quickly ran into my first problem. The motor fan was right over where I expected the pin to be. I saw that they put a straight knurl on the shaft and had pressed the fan onto the main shaft. I tried a gear puller but was worried I'd break the fan. I thought about it for a few minutes and decided to add a little heat as aluminum has an extremely high coefficient of expansion. Sure enough, with just a little heat applied (by little, I mean I was able to touch the parts in just a few minutes) and it pulled right off. Right underneath it was a pin staring me in the face. Seems they had been using the pressed on fan to retain the cross pin.

The cross pin tapped out easily with a punch but the actual internally splined piece wouldn't come out easily. I could get it to move but not much. Since I wouldn't be using it again anyway, a nut was welded to the end of it so I could screw a bolt down in and use it as a jack screw to push out the piece. Worked like a Charm!

Now all I've got to do is machine a keyed shaft with a 1.0000 diameter, a 3/8" hole cross drilled though it, and a 25mm diameter for the bearing to run on and I'm all set. Tap the pin back in, press the fan back on and put everything back together. This is much easier than bearing boxes and adaptor plates and I'll end up with a motor with a shaft I can replace pretty easily if something happens.

So, if any of you have these internally splined motors you are trying to find a use for, take a look inside and see if it's constructed the way mine is. You may have a lot easier conversion than you think.


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## dee1954 (Jan 9, 2012)

in regards to your ev-100 pics thats a fisrt generation ev-100s panel with small pot adjustments for creep and IA-time and controlled acceleration under a small sliding panel next to all the TB terminals


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