Importance

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Abstract

An elevator includes a manual active dynamic braking function, which elevator includes an elevator control for operating at least one elevator car in at least one elevator driveway between landing floors in response to elevator calls, an AC elevator motor, which is able to generate power in a generator mode, a motor drive connected to the elevator control for the regulation of the speed of the elevator motor, including a frequency converter, whereby the frequency converter of the motor drive includes a rectifier bridge and an inverter bridge with semiconductor switch circuits, which rectifier bridge and inverter bridge are connected via a DC link, the motor drive further including a drive controller at least to control the semiconductor switches of the semiconductor switch circuits of the inverter bridge to regulate the elevator motor to a reference speed, whereby the semiconductor switch circuits of the inverter bridge are provided with diodes connected anti-parallel to the semiconductor switches, the motor drive including a safety logic for cutting off control pulses to the semiconductor switches, at least during power outage, at least one elevator brake is located in connection with the elevator motor and/or with a traction sheave of the elevator motor, a manual brake release lever is functionally linked to the elevator brake, movable between a rest position and at least one operating position to release the elevator brake manually. The motor drive includes a bypass switch being arranged to operate the safety logic, as to enable dynamical braking of the elevator motor by connecting the semiconductors of the semiconductor switch circuits of the inverter bridge with the drive controller, and the motor drive includes a DC supply circuit connected with the DC link, which is arranged to feed DC power at least to the drive controller and to the bypass switch to enable dynamic braking control of the semiconductor switches. The manual brake release lever is functionally connected with the bypass switch and is arranged to operate the bypass switch, when it is moved away from its rest position. Alternatively, the elevator includes a manual actuator, such as a key switch, disposed in the same location with the manual brake release lever, whereby the manual actuator is arranged to operate the manual bypass switch.

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First Claim