REVOLVING SPEED CONTROLLING METHOD AND EQUIPMENT FOR AIR-DRIVE TYPE DRIVING DEVICE

PURPOSE:To obtain simple control over a rotor revolving speed by generating a magnetic field on at least one of the two members, a housing and a rotor, and making the magnetic field penetrate the other member, thereby making an eddy-current loss at either of the housing or the rotor so as to control the torque of the rotor. CONSTITUTION:Compressed air, which is introduced into a housing 1 from a supply port 3, acts on a moving blade 21 of a rotor 2, thereby rotating the rotor 2. After this, the compressed air is discharged from a discharge port 4. In this case, the rotor 2, for example, is made be a generating source of a magnetic field 5. As the rotor 2 rotates, the magnetic field M is moved relatively so that eddy current is generated at the through-part between the housing 1 and the rotor 2. Thus, the rotor 2 incurs an eddy current loss, which restricts the revolving speed of the rotor 2. Accordingly, the revolving speed of the rotor 2 at the time of no load can be lowered, and at the same time the load- related fluctuation in the revolving speed at the time of loading can be reduced.