Abstract: A pump motor controller for making pump motor speed independent of fluid pressure at the inlet and outlet of the pump. A first embodiment employs feedback to cause pump motor speed to converge to a desired speed established with a reference input signal. Based on this feedback, forward and reverse drive amplifiers in the first embodiment cause the pump motor speed to track the desired speed. A second embodiment employs a controller that produces drive signals to a stepper motor in proportion to a reference frequency. The controller and stepper motor in the second embodiment achieve speed control at low speeds without the use of a feedback control loop.