Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: Schlayer on September 29, 2015, 01:21:36 PM
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Yes, you read right. I don't know that it's been done before, but I'm sure it's doable. Long story short, I'm working with a team of fellow college students at the University of Rochester and we wish to replace broken or otherwise nonfunctional gasoline engines from a couple of riding lawn mowers with brushed DC motors.
We will be entering a competition called Solar Splash and ultimately our plan is to practice with a couple broken down mowers to prepare us for the conversion we'll use to power our competition boat, where we plan to replace the engine in a gas outboard with our hella-powerful 3-phase AC motor that was used in competition last year. We are also doing this since we happen to have two spare motors and controllers, some space in our budget, and driving quiet electric riding mowers around campus would be super awesome. ;D [At first we wanted to make Go-Karts, but the time and effort necessary to build a whole chassis and especially a steering mechanism and suspension would be far too great. Broken mowers are all over craigslist for next to nothing, and have steering, drive train, suspension, and brakes all working already, plus they are nearly all conveniently rear-wheel drive.] Currently though, we need to think of what kinds of problems the conversions might present, and how to overcome them. So far we have thought of the following issues:
- Instant motor torque, plus much greater torque than a gasoline engine of equivalent power output might produce, could damage the mechanics of the mower drive train
- Increased acceleration, due to the same thing, might tend to wheelie or flip our mowers (this shouldn't be an issue for the boat since outboard's can adjust their angle easily to compensate for planing)
- Trying to integrate a throttle control that works with our Alltrax golf cart Motor controllers into the controls for the mowers (depends on which ones we get, we're basically just finding mowers on Craigslist that are in decent shape besides a blown engine and are really cheap)
- We aren't sure how to mount the motor and couple it to whatever the gas engine's drive shaft was connected to
- I'm also concerned that there may be gasoline fumes and/or residue depending on how the engines failed, and attempting to weld near where the old engine was could be an issue??? Just speculation.
- We are powering our motors with 24V from two SLA car batteries in series (each) since the Solar Splash rules ban the use of any other kind of battery. Where would make sense to place them?
- Lastly, we are not planning on using these things as lawn mowers anymore, basically just like go karts or racing mowers, with all the grass cutting functionality removed and extra weight taken off. What parts can be removed from the mower easily? What are we certain is nonessential to driving it around (like the old cooling mechanism, transmission, and any kind of grass clippings ejection system)?
If you have any thoughts and/or suggestions, by all means let me know!
-- Schlayer