Reversible Motor
Reversible motors are often single-phase, fractional horsepower motors, meaning that they run on a horsepower (HP) of one or less or it can mean that their frame size is a 42, 48 or 56 according to National Electrical Manufacturers Association (NEMA) standards. Reversible motors are often utilized for applications requiring frequent changes in directions such as: in the automotive industry, for power steering system, powered seats and more; in the medical industry, for drainage pumps, mobility aids and a variety of other medical devices; in the food and beverage industry, for meat grinders, food processors, vending machines and more; and in the industrial manufacturing industry, for packaging machinery, compressors, conveyors, air conditioners and more. Additional industries that benefit from reversible motors include HVAC, commercial, wastewater, printing and textile.
Reversible motors have the same basic design as other types of fractional horsepower motors; they consist of an enclosure, rotor, axle, coil and field magnet. Some contain brushes, used to help conduct the electrical currents, but reversible motors may also be brushless, meaning that they require an external power supply to transfer the current. In addition to these basic components, reversible motors will have four terminals, which are connecting points at the ends of the conducting circuit of the motor through which the current may be conveyed into or from the motor. A reversible motor must have four terminals because it requires two terminals for the coil, also referred to as a wound armature, and two for the magnetic field. More commonly AC motors than DC motors, AC reversible motors can be single-phase or three-phase motors. In a single phase motor, the direction can be reversed by reversing the leads of the motor, while in a three-phase the direction is reversed by reversing the connections of one leg of the motor. The direction reversal is much different in a DC reversible motor, in which the polarity of the magnetic field is reversed in order to reverse the direction of the motor's rotation.
