Abstract: A method for estimating rope slip in an elevator system, includes: during a normal operation mode of the elevator system, determining whether one or more predefined operational conditions are fulfilled; and if one or more of the predefined operational conditions are fulfilled, estimating rope slip in the elevator system during the normal operation mode of the elevator system.

Abstract: In a system and method for an automatic rescue operation of an elevator car in an elevator system, the elevator system includes a hoisting machine and a battery-operated rescue drive device configured to provide power signals to the hoisting machine and/or hoisting machinery brakes. A load sensor is configured to gather elevator car load information, and the rescue drive device is configured to select, based on the elevator car load information, a first rescue run or a second rescue run.

Abstract: A brake is operationally coupled by gear engagement to an axle of a device, whereby turning on the brake prevents the axle from rotating. Monitoring condition of the brake includes driving the axle of the device in a first rotation direction when the brake has been turned on. The axle of the device is driven in a second rotation direction when the brake has been turned on. A first position angle of the axle of the device, which follows from driving the axle of the device in the first rotation direction, is measured. A second position angle of the axle of the device, which follows from driving the axle of the device in the second rotation direction, is measured. A clearance of the gear engagement of the brake is determined on the basis of a difference of the first and the second position angles.

Abstract: A method includes calculating a motor torque estimate for an electric motor of an elevator in an elevator run, determining a difference between the calculated motor torque estimate and a realized motor torque during the elevator run, and generating a signal indicating possible brake dragging based on the difference between the motor torque estimate and the realized motor torque.

Abstract: An arrangement in connection with a movable hoisting apparatus includes at least one imaging device and a processor provided in connection with the movable hoisting apparatus. The imaging device is adapted to save images which at least partly present the surroundings of the hoisting apparatus. The processor is adapted to identify at least one identifiable object from at least two images saved at different time instants and to determine the direction and speed of travel of the hoisting apparatus based on the position of the identifiable object in the images.

Abstract: A method with respect to a system that includes an electrical motor and a speed output unit, and the electrical motor is followed by a gear, wherein the following acts are performed by a processor of a controller of a motor drive: monitoring a first set of frequencies from the system over a measurement period when the system is in a known good operating condition; storing the first set of monitored frequencies or derivatives thereof as reference data in a long-term storage system, monitoring a second set of frequencies from the system over a measurement period when the system is in an unknown operating condition, comparing the second set of monitored frequencies with the first set of monitored frequencies in a frequency domain and in the frequency domain, detecting changes between corresponding frequencies resulting from the second set of monitored frequencies and the first set of monitored frequencies.

Abstract: A brake is operationally coupled by gear engagement to an axle of a device, whereby turning on the brake prevents the axle from rotating. Monitoring condition of the brake includes driving the axle of the device in a first rotation direction when the brake has been turned on. The axle of the device is driven in a second rotation direction when the brake has been turned on. A first position angle of the axle of the device, which follows from driving the axle of the device in the first rotation direction, is measured. A second position angle of the axle of the device, which follows from driving the axle of the device in the second rotation direction, is measured. A clearance of the gear engagement of the brake is determined on the basis of a difference of the first and the second position angles.

Abstract: A method comprising performing the following steps with respect to a system that comprises an electrical motor and a speed output unit, and the electrical motor is followed by a gear, wherein the following acts are performed by a processor operationally coupled to the system: monitoring a first set of frequencies from the system over a measurement period when the system is in a known good operating condition; storing the first set of monitored frequencies or derivatives thereof as reference data in a long-term storage system, monitoring a second set of frequencies from the system over a measurement period when the system is in an unknown operating condition, comparing the second set of monitored frequencies with the first set of monitored frequencies in a frequency domain and in the frequency domain, detecting changes between corresponding frequencies resulting from the second set of monitored frequencies and the first set of monitored frequencies, wherein the electrical motor is driven by a motor drive, and

Abstract: Method/apparatus for performing the following acts on a system that includes an electrical motor followed by a gear, and a speed output unit: monitoring a first set of frequencies from the system over a measurement period when the system is in a known good operating condition; storing the first set of monitored frequencies or derivatives thereof as reference data in a long-term storage system; monitoring a second set of frequencies from the system over a measurement period when the system is in an unknown operating condition; comparing the second set of monitored frequencies with the first set of monitored frequencies in a frequency domain; in the frequency domain, detecting changes between corresponding frequencies resulting from the second set of monitored frequencies and the first set of monitored frequencies.

Abstract: Method/apparatus for performing the following acts on a system that includes an electrical motor followed by a gear, and a speed output unit: monitoring a first set of frequencies from the system over a measurement period when the system is in a known good operating condition; storing the first set of monitored frequencies or derivatives thereof as reference data in a long-term storage system; monitoring a second set of frequencies from the system over a measurement period when the system is in an unknown operating condition; comparing the second set of monitored frequencies with the first set of monitored frequencies in a frequency domain; in the frequency domain, detecting changes between corresponding frequencies resulting from the second set of monitored frequencies and the first set of monitored frequencies.

Abstract: A motor control system for a hoist drive having an electric motor operationally connected to a hoisting member for hoisting a load, the motor control system being adapted to generate a final angular frequency reference (?*s) for control of the electric motor, the motor control system comprising a power limiter means adapted to generate a correction term (?s,cor) for angular frequency reference. The power limiter means comprises an integrating controller means, the power limiter means being adapted to generate the correction term (?s,cor) for angular frequency reference using output signal IP of the integrating controller means, initial data of the integrating controller means including information relating to actual value of the power of the electric motor and a power related limit value of the electric motor.

Abstract: To facilitate the use of a crane, an angle feedback information on a rope angle (?) of the crane is received, the angle feedback information being measured by means of a sensor at or adjacent to a trolley; and the angle feedback information is corrected by compensating an error caused by a speed change, and processed to provide movement instructions or other control information relating to the crane on the basis of real-time corrected angle information.

Abstract: A method according to the invention of controlling a rotation speed of a motor of a speed-controllable hoist drive comprises receiving a lift speed instruction; forming a final speed instruction by using initial information containing the lift speed instruction; and using the final speed instruction as a speed instruction for the rotation speed of the motor of the speed-controllable hoist drive. The method further comprises monitoring a position derivative of an actual value of a cable force. The initial information for forming the final speed instruction comprises the position derivative of the actual value of the cable force.

Abstract: A motor control system for a hoist drive having an electric motor operationally connected to a hoisting member for hoisting a load, the motor control system being adapted to generate a final angular frequency reference (?*s) for control of the electric motor, the motor control system comprising a power limiter means adapted to generate a correction term (?s,cor) for angular frequency reference. The power limiter means comprises an integrating controller means, the power limiter means being adapted to generate the correction term (?s,cor) for angular frequency reference using output signal IP of the integrating controller means, initial data of the integrating controller means including information relating to actual value of the power of the electric motor and a power related limit value of the electric motor.

Abstract: A method according to the invention of controlling a rotation speed of a motor of a speed-controllable hoist drive comprises receiving a lift speed instruction; forming a final speed instruction by using initial information containing the lift speed instruction; and using the final speed instruction as a speed instruction for the rotation speed of the motor of the speed-controllable hoist drive. The method further comprises monitoring a position derivative of an actual value of a cable force. The initial information for forming the final speed instruction comprises the position derivative of the actual value of the cable force.

Abstract: A method for starting the modulation of a frequency converter, which method comprises the steps of receiving reference voltages (sa, sb, sc; Uref), generating output switch commands from the reference voltages. The generation of output switch commands comprises further a step, in which the ratio (dz) of active time (T0+) in a modulation period (Ts) of selected zero vector and the total active time (T0++T0?) of zero vectors in a modulation period is changed from a first predetermined ratio, which is substantially 0 or 1, to a second predetermined ratio, which is substantially 0.5.

Abstract: A method and a system in connection with a speed and position sensorless permanent magnet synchronous machine equipped with an output filter and driven by an inverter, which method comprises the steps of forming a speed-adaptive full-order observer based on the dynamic model of the combination of the permanent magnet synchronous machine (PMSM) and the output filter, measuring the inverter output current (iA), estimating inverter output current (îA), determining the estimate for the electrical angular speed ({circumflex over (?)}m) using the estimated and measured inverter output currents (îA, iA) in an adaptation law, injecting a voltage signal (uc) into the inverter voltage reference (uA,ref 0) to obtain a modified voltage reference (uA,ref), detecting an error signal (?) from the measured inverter output current (iA), and calculating the speed correction term (??) used in the adaptation of the observer from the error signal (?).

Abstract: A method of controlling of an induction machine using an inverter is disclosed with output LC filter. The method includes determining an inverter output current vector (iA), determining an inverter output voltage vector (uA), and forming a full-order observer having a system matrix (Â) and gain vector (K). The observer produces an estimated rotor flux linkage vector ({circumflex over (?)}R), an estimated stator current vector (îs), an estimated stator voltage vector (ûs) and an estimated inverter output current vector (îA). An estimation error (iA?îA) of the inverter output current vector is determined, and a speed adaptation law is formed based on the estimation error of the inverter output current vector for determining an estimate for electrical angular speed ({circumflex over (?)}m) of the induction machine. The induction machine is controlled based on the produced estimates and a measured inverter output current.