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CONTROLLING AIR MOTORS Speed regulation

Pressure regulator Controlling the speed and torque of an air motor is achieved byregulating the air supply; a relatively cheap and simple operation. Two methods are available, throttling and pressure regulation. The air flow is controlled by placing a flow control valve at the inletport or the outlet port of the air motor. Throttling will reduce the maximum speed of the motor but will not affect the starting performance; the air pressure is unaffected at low flow conditions i.e. starting. Note the difference in the graph between throttling on the inlet port and outlet port. The speed and power can also be reduced by installing a pressureregulator on the incoming air supply. The pressure regulator reduces the air pressure to the motor. A pressure regulator is always fitted on the inlet port. By using a pressure regulator the torque on the output shaft will be affected, starting torque is best controlled with this method. When both the speed and the torque are to be controlled the bestconfiguration is to use a pressure regulator in the line to the motor and a flow control valve on the outlet port. This way every point in the torque-speed graph can be set accurately. Throttling

Throttling methodsPressure regulating method

Inlet throttling,uni-directional motor. Pressure regulation, uni-directional motor.Outlet throttling,uni-directional motor.Inlet throttling,bi-directional motor. 5