Single-Speed HSM Motor Operation

These motors use a slotted rotor with vanes that move radially against a cam ring. As the rotor turns, the vanes follow the contour of the cam and slide in and out of the slots.

The vanes are spring loaded against the cam ring with a pressure balance design. As the rotor turns, sealing is augmented by centrifugal force.

The ring contour forms four equally spaced pressure quadrants. These quadrants consist of transitional ramps or "lobes". Fluid is delivered to the "lobes" through slots in the mating surface of one of the covers.

In single-speed models, a single-port cover delivers pressurized fluid to two sets of the diametrically opposed and balanced lobes. This causes the rotor to turn.

Movement of the rotor transports fluid to the slots in the opposite cover, out the other port and back to tank. As the rotor turns, it drives the shaft which is spline connected to the rotor.

The direction of shaft rotation is determined by which cover port is pressurized.

  
Multiple-Speed Models

In circuits using fixed-displacement pumps, multiple-speed motors can reduce input horsepower requirements. The machine operator can select the most desirable speed/torque combination during different phases of the operating cycle.

Two-speed motors can operate at full torque at one speed, or at double the speed with half the torque. These models utilize a two-port cover, with each port independently connected to a separate set of diametrically opposed cam "lobes" of equal displacement.

Three-speed versions also use a two-port cover with each port independently supplying one set of two "lobes". In these models the cam ring contour forms "lobe" sets with unequal displacements.

Speed and direction of rotation are determined by which pair of ports, and consequently which set of "lobes", are supplied with fluid. The machine operator can select either minimum, medium or maximum speed. Speed and torque are determined by the various displacements of each specific motor model.

Refer to the "Selection Tables" for complete motor specifications.