Hitachi, Ltd.

Hitachi Elevator Engineering & Service Co., Ltd.

Hitachi Engineering Service Co., Ltd.

Yoshimitsu Onoda

Hisakatsu Kiwaki

Takato Yamakoshi

Masahiko Ibamoto

Shotaro Naito

Kyozo Tachibana

Tatsuo Horie

Katsuaki Suzuki

Shozuchi Miura

Hiroshi Goko

Shigeru Arakawa

A controlling device for a permanent magnet synchronous motor wherein a permanent magnet is used as a rotor and which includes three-phase armature windings comprises a detecting means for detecting a rotational position and a rotational angle of said rotor, a comparison means for comparing the rotational speed detected by said cetecting means with a predetermined reference speed and for developing a value of a difference between the rotational speed and the reference speed, a converting means for determining currents to be supplied individually to said armature windings in response to a vector value obtained from the rotational position detected by said detecting means and the value of the difference delivered from said comparison means, and a current controlling means for controlling current flows through said individual armature windings in response to values obtained by said converting means.

Controlling method and device for permanent magnet synchronous motor

An emergency control system for an elevator has a circuit for producing a signal in response to a relatively small vibration of a structure in which the elevator is installed; a first circuit responsive to the signal for controlling the operation of the elevator under a predetermined mode for a first predetermined time interval; and a second circuit for disabling the signal producing circuit simultaneously with the start of operation of the first circuit and enabling the signal producing circuit for a second predetermined time interval longer than the first predetermined time interval.

Emergency control system for elevators

A supervisory operation control system responds to detection of vibration occurring at a predetermined location of an equipment for causing the equipment susceptible to adverse influence of the vibration to perform a predetermined supervisory operation. Transition to the supervisory operation is enabled when a product of speed and displacement of the vibration exceeds a predetermined value.

Supervisory operation control system for protecting elevators or the

The two secondary windings of a transformer the primary winding of which is connected to an AC power supply are each provided with a controlled rectifying circuit. The DC sides of the rectifying circuits are connected in series to supply power to DC motors. One of the secondary windings is detachably connected with a capacitor bank. The capacity of the capacitor bank is selected so that the power factor of the converter can be improved to a satisfactory value when the two rectifying circuits are both controlled to produce output voltages. The capacitor bank becomes connected in response to the fact that the current in the primary winding of a transformer has arrived at a predetermined value.

Power factor improving apparatus for power converter

In cases of subjecting an electric motor operated vehicle to electric braking, regenerative braking is performed during the first stage of the braking operation thereby supplying the armature current to the battery as a load, and a plugging operation is performed during the last stage thereof to complete the braking operation, whereby the efficiency of operation is enhanced by conserving the armature current to extend the traveling distance of the vehicle per charge of the vehicle battery, and the generation of excessive heat in the motor is suppressed.

Growing community of inventors

Toride, Japan

Yoshimitsu Onoda