Current limiting DC motor

[Makaram]

Hey guys, running a small chainsaw sharpener motor with its 9.6V battery in a custom job. Unsure of the running specs of the motor itself, but would like to create a timer circuit to control the motor.
Question is whats the best way to limit the current of the circuit so i dont ruin the battery (battery specifies .7Ah)
Do i need to be limiting the current? or does the motor itself provide enough resistance to reduce it to an acceptable level?
running 20 1W resistors in parallel doesnt seem like a very clean option either,
thanks for any assistance

p.s. would be idea to have current limited to at least below 3A as thats the max current my darlinton transistors can handle

 

[carbonzit]

Normally we limit current to devices that can draw excessive current under some conditions (like LEDs), not to circuits that are handling such loads. In other words, your timer should be robust enough to handle whatever the motor draws, because if you reduce the motor's current, you also will probably reduce its speed, torque or both. So if your transistors can't handle it, then you should get some bigger transistors (current-handling wise).

One thing you should do, since it's a DC motor, is to put a "snubber" diode across it to absorb any reverse inductive "kick" (you'll find tons of info on this by a simple search).

 

[Makaram]

Hey man thanks for the advise,
One of my main concerns the batteries capacity to maintain this unlimited circuit??