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Author Topic: Powering an R/C Mower  (Read 3584 times)

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Offline dave.mTopic starter

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Powering an R/C Mower
« on: July 07, 2007, 11:40:02 AM »
Hi all,

I'm attempting to build an R/C mower and wondering if two 350 watt motors (each running from 24 Vt's) would likely have enough power to do the work.   (They'd each be geared to go from an 11 tooth to a 56 tooth sprocket attached to 10 in diameter tires). 

Let's assume this thing will weigh in around 100lbs.

The idea is for the two motors to work together turnstile for forward direction (for 700 watts total),  opposite directions for turning, etc.

Guys, I realize that this is not a lot of info and apologize in advance -- Just wanted to get a feel from the community as to whether it stood a chance.

Oh!  I'd also be interested in suggestions for an Bridge controller that can 1) handle R/C commands for 2) controlling two motors in they way I mentioned here.

Thanks all!


Offline KambeiX

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Re: Powering an R/C Mower
« Reply #1 on: July 07, 2007, 11:50:39 AM »
If you don't need 0 ratio turning you can just use relays.

Offline Kohanbash

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Re: Powering an R/C Mower
« Reply #2 on: July 07, 2007, 08:02:54 PM »
Hi your probably ok on flat ground assuming that your power source can dish out the needed current. You might want to avoid point turns since it will cause a buildup of grass/dirt along the sides of the wheel causing a higher current draw (more torque is needed), instead turn using arcs by having different velocities on each side of the mower. Also its hard to say without seeing your tires, grousers, and center of gravity but you will probably be limited to about 20 degree hills while still being able to have control over the mower.
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Offline dunk

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Re: Powering an R/C Mower
« Reply #3 on: July 08, 2007, 03:55:53 AM »
hi Dave,
i don't think you have provided enough information about your motors for us to properly decide whether your mower will be geared properly.
what is the RPM of your motor unloaded at 24V?
do you know the torque?

my hunch would be that you are going to need a lower gear ratio than 11/56 for 10 inch wheels but i can't really be sure without knowing more about your motor.

these motors will definitely work if you gear them low enough but obviously that affects the speed.
what is your desired top speed?

for speed controllers, etc.
you might want to look at web pages specialising in robot wars style battlebots.
the people building those often have the need for high power motors like you plan to use.

also, these guys are building some pretty heavy RC projects: http://www.rctankcombat.com/


Offline dave.mTopic starter

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Re: Powering an R/C Mower
« Reply #4 on: July 08, 2007, 11:12:12 AM »
dunk -
  Thanks for your help.  I believe the motor runs at 2400 RPM (unloaded) at 24 vts.  I don't have info on the torque - just that it's 350 watts @ 24wts.

  Also, I'm looking to power the motor using two 12 vt 18ah SLA batteries -- is that close to reasonable?

  Thanks again for your help and I apologize for not having all the info..




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