Which type of motor has torque that varies inversely with speed?

The most appropriate choice is the constant horsepower motor. This type of motor maintains a constant output power, which is the product of torque and speed. As the speed of the motor increases, the available torque decreases to keep the power output constant, establishing an inverse relationship.

For instance, if the motor is designed to operate at a specific horsepower, and it is running at a high speed, the torque must drop to maintain that horsepower level. This inverse relationship is a fundamental characteristic of constant horsepower motors across their operational range.

In contrast, a variable-torque motor is designed for applications where the torque output varies with the square of the speed, which is not the same as the inverse relationship found in constant horsepower motors. Wound-rotor motors and single-phase motors have different operational principles and do not exhibit this specific inverse behavior between torque and speed in the same way that constant horsepower motors do.