A motor control system comprising:
- a casing;
- a blade-type motor including a rotor chamber in which a rotor is positioned;
- said motor being mounted in said casing;
- a rotary air distributor positioned inside said casing for both rotation about and movement along its axis;
- said distributor being freely slidably movable along its axis to at least a limited extent;
- a manually operated actuator positioned externally of said casing and connected to said distributor for permitting the manual rotation of said distributor;
- one end of said rotor chamber being defined by an end wall having first, second, and third flow ducts extending through said end wall and positioned with a spacing of 120.degree. between adjacent ones of said flow ducts;
- said first flow duct always comprising an outlet opening for discharging exhausted drive air with said second and third flow ducts being of the same size and shape and being alternatively employed as either an inlet opening or an outlet opening in accordance with the rotational direction selected for the motor;
- wherein said distributor includes an inner end facing said end wall and which inner end includes an outflow chamber which is in communication with said first flow duct for all rotary positions of adjustment of said distributor;
- outlet duct means in said distributor communicating said outflow chamber with the atmosphere;
- said distributor additionally including a compressed-air supply duct having an inner end in facing relationship to said end wall and having an outer end connected to a source of compressed air;
- a seal joint fixedly mounted on the inner end of the distributor and including a central opening surrounding said inner end of the compressed-air intake duct and having an outer surface facing said end wall to provide a sealed connection of said air supply duct with said one end wall for all positions of adjustment of the distributor;
- means for urging said distributor axially toward said end wall;
- and
- wherein said distributor is capable of rotation from a first position in which the inner end of said compressed-air supply duct is aligned with said second flow duct and said first and third flow ducts communicate with said outflow chamber so as to effect rotation of the motor in a first direction through an intermediate position in which said inner end of said compressed-air supply duct is blocked by said end wall so that the motor does not rotate to a second position in which the inner end of said compressed-air supply duct is aligned with said third flow duct and said first and second flow ducts communicate with said outflow chamber so as to effect rotation of said motor in a second direction opposite to said first direction.