Otis Elevator Company

Masao Iwasa

Yasutami Kito

Masayuki Mori

Hirofumi Sugiura

Koji Yamada

Eiji Narumi

Atsushi Iwakiri

A single inverter ( ) provides variable frequency, variable voltage current output ( ) to either a hoist motor ( ) or a door motor ( ), depending on the operating mode of the elevator car ( ). A controller ( ) provides an input signal ( ) to an actuator ( ) for switching the output current ( ) between the motors ( ) by a relay switch ( ). The controller ( ) includes separate control profiles depending upon which motor ( ) is connected to the inverter ( ).

Single inverter controller for elevator hoist and door motors

A traction-type elevator includes a driving sheave (19) arranged in an upper portion of an elevator shaft, cage sheaves (6, 7) arranged at an angle with respect to the driving sheave (19) and mounted on a support beam (5), multiple (or turns of a rope) ropes (17) hung on the cage sheaves (6, 7) and the driving sheave (19), and a hanging rod (10) for hanging a cage from the support beam (5). In this traction-type elevator according to the invention, one torsion coil spring (16) is arranged between the cage side and the aforementioned support beam (5) appropriately so that the aforementioned hanging rod (10) is inserted through it; the two ends of torsion coil spring (16) are attached to a cage side and a side of the support beam (5), respectively. The support beam (5) can effectively rotate to relax torsion in the ropes (17), and it is possible to suppress generation of vibration by the torsion. Also, the torsion coil spring (16) can play the role in damping vibration without shifting outwardly.

Traction type elevator

In a traction-type elevator equipped with a driving sheave (16) positioned at the top of the shaft for ascent and descent (1), cage sheaves (4, 5) are attached to the upper section of the cage (2) and are inclined in relation to this driving sheave (16), and multiple ropes (12, 13, 14) are wound around the outer surface (4a) of this cage sheave and the outer surface (16a) of the above-mentioned driving sheave; the traction-type elevator is characterized in that along with making the outer surface (4a) of the above-mentioned cage sheave (4) parallel to the outer surface (16a) of the driving sheave (16), this cage sheave (4) is divided into multiple sheave pieces (17, 18, 19) according to the abovementioned ropes (12, 13, 14). The ropes (12, 13, 14) are pulled by the driving sheave (16), and even if the cage (2) is caused to move upwardly or downwardly at a high speed, there is essentially no more generation of vibration and noise, because none of the abovementioned ropes (12, 13, 14) twists undesirably.

Traction-type elevator

The current an inverter is used as a power source for a brake circuit. The brake circuit includes a current detector, a comparator for comparing the detected value with a dictated brake current pattern, and a switch which switches the brake current in accordance with the magnitude of the difference between the detected current value and the dictated value. The brake current is selected to smoothly increase and decrease the brake current to prevent vibration and noise.

Brake control system in elevator control apparatus

The DC offset in a current control system for a PWM inverter drive is corrected by integrating a DC component of a current control signal provided by a current control amplifier and feedback controlling the current control amplifier to reduce the DC component to zero.

Offset correction circuit of PWM inverter

Alternating current motor control system with emergency control

A clipper circuit includes an auxiliary diode connected between a capacitor and diode, themselves forming a clipper circuit. The auxiliary diode thus forms an auxiliary clipper circuit taking the capacitor as a common capacitor. The clipper circuit diodes shunt current from the capacitor into first and second currents through the diodes. This obviates the necessity for a snubber circuit and power source clipper circuit as employed in the prior art.

Clipper circuit for power transistor circuit and inverter circuit

A simplified elevator power system using an AC-DC converter, both to convert AC to DC during normal operation and to convert stored DC power to AC during power failures. A power source monitoring relay monitors AC power coming from a utility, and upon power failure, switches a battery from a charging mode to a power source mode wherein DC power is supplied, not only to an inverter for driving a motor, but also to a converter hooked up to run as an inverter during such power failure in order to provide stepped-up AC voltage to elevator control devices. In this way, the prior art addition of an extra inverter is avoided.

Elevator power source device

The present invention is achieved with a control unit for a PWM inverter for comparing (8) a voltage command signal (7) with the fundamental of the inverter's output voltage waveform and for comparing (11) the result with a carrier signal (10) and using that result to keep the output voltage waveform equal to the voltage command signal. The use of the output's fundamental for feedback eliminates the prior art need to use slight delays in the inverter's switching stage thereby removing the prior art torque ripple and consequent vibration problems particularly at low speed and furthermore enables smoother stopping and starting control using variable speed ranges of several hundred to one.

Growing community of inventors

Chiba, Japan

Masao Iwasa