Originally Posted by
Mike Henderson
In a electric motor, HP is torque times RPM times a constant factor. As you slow down a motor, the HP will decrease. This is true whether the motor is slowed down by an external unit or an internal unit. Richard references an internal unit that will maintain the speed, but that just maintains the HP at that RPM - it doesn't increase it.
I've had a pretty good success in using those external "router speed control" units. As Jim said earlier, they're intended for dumb routers, not one with slow start. They're not very expensive so if you want to try one, go ahead.
There is an issue of cooling because the internal fan is running slower so check the temperature (with your hand) occasionally.
Mike