A commutation circuit for an inverter using an auxiliary source to accumulate the energy for commutation is simplified by assigning to the main diodes mounted in series with the main thyristor of the inverter the role of preventing partial discharge of the storage devices during the commutation process.

In a three-phase AC voltage control circuit containing reverse parallel connections of a thyristor and a diode or reverse parallel connections of thyristors in at least two phases, each asymmetrical AC voltage obtained by applying a line voltage of the power source having 30 degrees of phase lead from that of the phase voltage of the power source in the phase containing the thyristor to each polarized delay circuit is used as the power source for a firing angle control circuit of the thyristor i…

A convergence apparatus in a color CRT display scanning the display surface by a plurality of electron beams, comprising convergence coils for pole pieces which impart electromagnetic action to the electron beams and a transistor circuit for superposing both of the horizontal and vertical convergence correction currents to each of the convergence coils whereby the precise convergence correction is attained.

In conventional disk shaped recording reproduction devices, vibrations have been absorbed by the up and down motion of protruding rods which are supported in a viscous liquid such as a silicon oil. According to this invention, an inexpensive elastic body is used, which is heated by a heater so that, by maintaining the temperature of the elastic body within a certain range, the deterioration of the vibration absorbing characteristics of the elastic body with temperature changes is considerably re…

A convergence apparatus in a convergence circuit of a CRT, comprises, Means for dividing a horizontal parabolic waveform voltage in suitable voltage levels corresponding to a vertical parabolic waveform voltage; means for shaping the waveforms of the divided voltage signals; means for composing the shaped voltage signals to give the shaped covergence correction voltage signal; and Means for feeding the current corresponding to the shaped convergence correction voltage signal waveform to a conver…

A traction machine of a traction type elevator with a detector operable at occurence of abnormal car traveling. The traction machine includes a painting system to operate at the necessary time to paint the traction surface of a traction sheave of the elevator and at least one of main ropes near the traction sheave with a friction increasing material. It may include a foreign material remover to operate at the necessary time to rub the traction surface of the traction sheave. The painting system …

In a gas interrupter, high pressure gas such as air and SF.sub.6 is puffed to an arc so as to perform the extinction of the arc and a part of the passage of the arc is limited to narrow space and the arc voltage is raised at the narrow part and the other part of the passage of the arc is kept in wide space and the puffing rate of the high pressure gas is kept high enough at the wide space.

An alternating current generator for charging a battery has a radio noise suppressing capacitor. One terminal of the capacitor element is press-contacted with the bottom of a hollow part formed in a bracket and the other terminal of the capacitor element is press-contacted with a conductive member connected to the output terminal of the generator in the holding of the capacitor. The parts can be decreased and the quality can be improved.

A ventilator of a distributor for ignition of an engine comprises a ventilation plug molded by an insert molding in a molding of the cap of the distributor. The ventilation plug having a ventilation hole and passage is fixed on the cap in rigid.

A magnetic disc recording apparatus comprises flow control partitions disposed near peripheral parts of rotary magnetic discs whereby air involved between magnetic discs or between magnetic disc groups is controlled.