Low speed resistor and stall protection assembly for engine cooling fan motor

A resistor and stall protection assembly for a permanent magnet brush-type DC motor, the assembly comprising:

• means for reducing voltage to the motor thereby permitting the motor to operate at a speed less than a speed of the motor when voltage to the motor is not reduced,
• first means for connecting the assembly to a source of power,
• second means for connecting the assembly to the motor,
• means for sensing a motor stall condition, and
• means for interrupting power to the motor when the motor is in the stall condition.

A method of sensing stall of a permanent magnet brush-type DC motor, the method including:

• providing a first speed circuit for operating the motor at a first speed,
• providing a second speed circuit for operating the motor at a speed greater than the first speed,
• determining if a stall condition of the motor occurs, and
• when a stall condition is determined to have occurred, interrupting current to the motor.