Although the speed oscillated slightly, the total inertia made it effectively a constant-speed motor.

Conventional heat pumps use constant-speed motors that require the compressor to turn on and off frequently to maintain a desired room temperature.

The combination of a constant-speed motor and a continuously adjustable mechanical speed-changing device might also be called an adjustable speed drive.

The process of determining the target's motion vector was done primarily with an accurate constant-speed motor, disk-ball-roller integrators, nonlinear cams, mechanical resolvers, and differentials.

None of them kept good time, and several of them, since they were powered by constant-speed motors driving very simple gearboxes, could not be adjusted, but had been sent out from the factory with built-in, ineluctable inaccuracies.

Of note, for about a century, some variable-speed electric motors have had decent efficiency, but they were somewhat more complex than constant-speed motors, and sometimes required bulky external electrical apparatus, such as a bank of variable power resistors or rotating converters such as the Ward Leonard drive.

Controls and Instrumentation: Constant power / constant speed motor controller.