Abstract: An electric motor is provided with especially brushes of which rear ends are cut diagonally to form acute angles at the corner edges on the backward side of the rotating direction of the armature. The brushes are maintained securely in brush holders without vibration by first and second side walls of the brush holders according to component force of pressing force applied on the slant rear ends of the brushes by pressing members, therefore the objectionable noise caused by the "stick-slip" is prevented very effectively without introducing complicated structure in the motor.

Abstract: Cooling air is introduced through an opening in a wall portion of the motor housing radially opposing the commutator. A deflecting surface is provided for deflecting the cooling air entering the motor through the opening away from the commutator and toward the armature so as to prevent direct contact of dust and moisture in the cooling air with the commutator.

Abstract: An air induction system for an automotive air-conditioner has an air switching housing connected to the suction opening of a blower casing. The housing is provided with a fresh outdoor air induction opening formed in the top wall opposing the suction opening, and a recirculated indoor air induction opening formed in a side wall adjacent to the top wall. An air-switching door is provided for selectively opening and closing the outdoor air induction opening and the indoor air opening. The air-switching door is foldable substantially at its mid portion so that, when the door closes the indoor air induction opening, it is folded to provide a small effective area, while, when it closes the outdoor air induction opening, it is extended to provide a large effective area. The system further has auxiliary indoor air induction openings formed in other side walls and an accordion-type shutter for selectively closing and opening the auxiliary indoor air induction opening.

Abstract: Provided is a brushless-motor fan unit having a centrifugal fan and a scroll casing enclosing the centrifugal fan therein. The rotor of the brushless-motor is carried by the centrifugal fan. Further, the motor shaft carrying the centrifugal fan is supported at its front and rear ends by the scroll casing. With this construction, the motor housing can be eliminated so as to obtain a compact centrifugal type motor fan unit in a small thickness as a whole.

Abstract: A rotational speed control circuit for a D.C. motor includes a power transistor with its emitter-collector path connected in series with the D.C. motor and a power supply. A base current of the power transistor is controlled by an output of a differential amplifier which is supplied at its one of input terminals with a constant voltage and at the other input terminal with a voltage changing in accordance with a terminal voltage of the D.C. motor. Further the latter input terminal of the differential amplifier is given a variable bias potential by means of an adjustable mechanism. By this circuit configuration, the rotational speed of the D.C. motor can be continuously and proportionally adjusted over a wide range and once the rotational speed is set to predetermined value by the adjustable mechanism, a stable and constant speed control for the D.C. motor can be achieved.

Abstract: A rotor for a flat-type motor is constructed to include a flat armature, which comprises a flat armature winding in the form of a disk, and an insulating resinous body in which the armature winding is embedded. The insulating resinous body has a greater thickness than the armature winding so as to cover the winding, but is formed with cooling structure, such as grooves and bores, in positions where the coil portions of the armature winding on which the magnetic flux of the field magnets acts effectively are embedded, thereby promoting dissipation of heat from the armature winding.