electric motor for riding mower conversion
 

Hi all, I'm working on converting my Toro Zero Radius Turn mower to electric after its engine died last summer. Is there any place better to buy electric motors than from electricmotorsport.com?

This mower had a 16hp Briggs & Stratton engine. Does this mean I need an electric motor capable of 16hp, or does the load of a riding lawnmower typically require less hp than the engine is rated? I'm wondering what the lowest hp electric engine it is sensible to use for this project.
Thanks.

You should be able to get away with a 2 to 3 hp electric motor because that HP rating is for continues use but the peek HP rating tends to be much higher and on top of that it's not as easy to stall an electric motor very easily, instead of stalling they tend to put out their peek Horse Power!
I think the GE electrac garden tractors have a 6" motor on them and that seems to be around the size that most people tend to go for when converting as well.

My Simplicity mower originally came with an 8hp engine. My electric setup is a Motenergy ME0708 motor running at 48V. It typically pulls 70A during normal mowing and 100A going through real thick/tall grass. At 70A, the motor is putting out roughly 4.5hp. So, during normal usage, the gas engine was only using roughly half the horsepower it has. At the peak ratings I've seen (100A draw), it is still only pulling 6.5hp. The ME0708 is rated for 6.4hp continuous and 20hp for 1 minute. So, I'm well within its rating and I'm sure it'll last forever.

Before I got my ME0708 I was using a series wound dc Baldor motor rated for 1.2hp. It lasted about a year and a half before I ended up overheating it. If I would have added a fan to that motor I would probably still be using it though. So, you can get away with a much smaller electric motor. Is it harder on the motor, yes. Does it work, yes. How long will it last? I don't know. :)

So, as a conservative guess, I'd say you're generally alright going with a motor rated around half the gas engine's power rating. For your purpose, an ME1004 (which is basically made to replace small gas engines) or ME1003 would probably work out great. You could get away with an ME0709 probably, but for the minimal price difference I don't think its worth it.

I like the PM motor for motors better for the mower. The rpms are much more constant when the motor is loaded vs not as loaded. With the series wound motor, it would speed up when I disengaged the blades noticably. It is hardly noticable with the PM motor.

Also, the prices on that site seem fairly reasonable. I know I can get the ME1003 motor for $450 from Motenergy locally since its just a few miles away. So, the markup isn't too crazy high.

Thanks, Daox. Do you agree with Ryland that I'd be able to make use of a motor of less than 10HP?

10hp continues or 10hp peek? my car has a 6hp continues rated motor in it but puts out around 45hp peek, my electric push mower has a half hp motor on it, the GE electrac tractors tend to have half to 3/4hp motors on each of their mower blades (one motor per blade) and it might take 1.5hp to drive the tractor around and up hills, but going a little larger seems like a good idea unless you want to add a cooling fan to the motor.

I wrote to electricmotorsport.com and asked them about a suitable motor for my mower. This is the one they suggested.

Electric Motorsport EV Parts

It looks like that should be plenty of power for my application and the price is within my budget so I think I'll probably go with this one unless someone knows of a cheaper/better motor than this. Thanks!

If I had to choose one that is also the motor I'd choose. Here is the manufacturer's site and the ME1004 description:

ME1004 Brush-Type DC Motor

Those motors are way smaller than a forklift hydrolic motor. Are the forklift motors a bad choice to big for a mower conversion?

The main reason these motors are smaller is because they have an open frame design for cooling. This means less heat build up so you can pack more power in a smaller package.

Motor rating is mostly about heat dissipation. You can run a 1hp series wound motor at 50 hp for a split second. If nothing melts and you don't ruin the bearings you're good to go. That is why my 1.2 hp motor could put out 5 hp for half hour spurts for a year and a half.

The other advantage of the permanent magnet motors is they keep a more constant rpm as I mentioned in my first post. Its not that a series wound motor is bad, it just changes rpm more based on the load put on it. Series wound have other advantages though, but they don't really apply much to a mower type setup.

Now, I think I've seen both series wound and permanent magnet motors used in forklifts as pump motors. I think the easiest way to identify a series wound motor is that it normally has 4 posts on it versus 2 posts for wires.