Question on DC motors: Getting hot and no power:Sabertooth 2X25 MY1016 Motors

[justindp2006]

IF MORE INFORMATION IS WANTED, PLEASE JUST LET ME KNOW

OK, not sure if this is best place to ask but figure best place to start. I built a RC Lawnmower. The electrical is very simple. I used the Sabertooth 2x25A Motor driver by Dimension Engineering. I am also using MY1016 "scooter" motors. Ratings are 24V 280W 15.5A @ 2750RPM. There is a 30A Automotive Switch on + to the driver board to kill circuit. I used 12V battery source at first (one car battery) and it did oooooK I guess but was slow and no power. I put car battery 2 in series and it made difference but still week. Also, motors got so hot they were blowing smoke... Gear ratio is 1:5 right now. Maybe I'm wrong, but two of these motors should have some umph behind it, but I get stuck in a rut... and using 24V they're smoking after about 15 min of use. Help? This thing is gear the same as the scooter 5:1. Just frustrated as all this time and money put in this and now I'm stumped.

Here is link to album of my mower if anyone is curious and wants to see what I'm working with.

http://imgur.com/a/ib2hS#0

[jkerns]

With permanent magnet DC motors at a high duty cycle (or constant on), if the motor is turning slowly the current is much higher than when they are turning fast. So, if you load up the motor and force them to turn slowly many will overheat and potentially burn out due to the excess current.

It sounds like this is what is happening with your system - the motors do not have enough torque to get your device moving fast enough to allow the motors to spin at their rated speed. You can change your gear ratio to allow the motors to spin faster or you can get more powerful motors.