Originally Posted by Salty9
I was wondering about this as the duty cycle of most starters in the states is less than a minute but according to Al's blog it is not one of our starters.
I agree that the duty cycle of most starters is less than a minute. In fact, they are typically designed to run for only 10 seconds, then need a break for around a minute.
However, when put on a go kart, it does not have to turn over a gas engine, hence, why I could run mine for longer than 10 seconds.
However, the modified starter motor did get extremely hot as there are no cooling fans, fins or liquid cooling. I often had a bottle of water near by to pour on the motor when it got hot. I'm now working on cooling systems for the motor as I believe I can get more power, torque and have the motor last longer if I implement cooling on the motor.
The starter motor I modified for my Electric Go Kart
is typically found on some Kohler gas engines, some John Deere equipment and some B&S gas engines.
Unlike most starter motors you find on cars & trucks, where there is a solenoid to throw the pinion out, this style of starter motor has grooves on the shaft and when the spins, the pinion is thrown out. I simply removed the springs and locked the pinion (with the welded sprocket) into position by packing washers on the shaft.
Some early model English cars also had this style of starter motor.
In the future, I am looking to modify a 24volt starter motor similar to that found on diesel trucks. This one will have a solenoid that throws the pinion out, so I will have to work out how to deal with that one.
Also, I believe a lot of those starter motors are series wound DC motors so if I want to reverse it, I will need to do more modifications. This will involve separating the field winding circuit from the armature circuit.