Abstract: The invention relates to a method and an apparatus for determining the movement of a synchronous machine. The apparatus for determining the movement of a synchronous machine comprises a determination for at least one electrical magnitude of the synchronous machine; a determination of the position error of the rotor of the synchronous machine, which is fitted to determine the position error of the rotor on the basis of the aforementioned at least one electrical magnitude of the synchronous machine; and also a correction of the movement signal of the incremental sensor, which is fitted to correct the read movement signal of the incremental sensor on the basis of the aforementioned determination of the position error of the rotor of the synchronous machine.

Abstract: A method for restricting the output of an electrical drive and for protection of an elevator are provided. The electrical drive includes a motor as well as a power supply appliance of the motor. In the method for restricting the output of an electrical drive the stator voltage vector is restricted to its limit value restricting only the component of the stator voltages in the direction of the q axis. In the protection of an elevator, the elevator includes a machinery brake, a safety brake of the elevator car, and also an electrical drive. The protection method includes determination of at least one limit value, restriction of the output of the electrical drive on the basis of at least one determined limit value, and restriction of the movement of the elevator car on the basis of at least on determined limit value.

Abstract: The invention relates to a frequency converter, and also to a method for determining the position of the rotor of an electric machine. The frequency converter comprises a load bridge and also a control of the load bridge, for supplying electricity between the load bridge and an electric machine connected to the load bridge. The frequency converter comprises a determination for at least one electrical parameter of the aforementioned electric machine, and the frequency converter comprises a determination for the position of the rotor of the aforementioned electric machine. The load bridge is fitted to supply a first alternating electricity excitation signal, which is formed in relation to the electrical angle of the electric machine, to the aforementioned electric machine.

Abstract: The invention relates to a method and an appliance for monitoring the safety of a transport system (1). The transport system comprises a transport appliance (2) and also a synchronous motor (3) for moving the transport appliance. In the method the motion information of the transport appliance is determined with two channels, and if the determined motion informations deviate from each other by more than the set limit value, an emergency stop is executed.

Abstract: A determination of the loading state of an elevator system and also a method for determining the loading state of an elevator system is described. The elevator system includes an elevator car and also a motor drive for moving the elevator car. The loading state of the elevator system is determined on the basis of the position deviation of the elevator motor that occurs during the determination of the loading state.

Abstract: The invention discloses a method for restricting the output of an electrical drive, and also a protection of an elevator. The electrical drive comprises a motor as well as a power supply appliance of the motor. In the method for restricting the output of an electrical drive the stator voltage vector is restricted to its limit value restricting only the component of the stator voltage in the direction of the q axis. In the protection of an elevator, the elevator comprises a machinery brake, a safety brake of the elevator car, and also an electrical drive. The protection of an elevator comprises a determination of at least one limit value, a restriction of the output of the electrical drive on the basis of at least one determined limit value, and also a restriction of the movement of the elevator car on the basis of at least one determined limit value.

Abstract: The invention concerns a method and an apparatus for controlling a three-or-more-phase motor driven by a frequency converter. In the method, a change-over switch of the frequency converter is controlled to a continuously conducting state and at the same time the phase voltages or phase currents of the other phases are controlled by switching the change-over switches in those motor phases at a switching frequency substantially higher than the frequency of the fundamental wave of the phase voltage or phase current. The apparatus comprises in conjunction with the frequency converter a number of change-over switches, at least one change-over switch for each motor phase. The change-over switches comprise controllable change-over contacts. The apparatus further comprises in conjunction with the frequency converter means for determining the motor phase currents and means for controlling the change-over contacts.

Abstract: The invention concerns a method and apparatus (28) for determining an angle (9) by means of a resolver (3). In the method, an excitation signal (29) of constant frequency is supplied to the resolver (3), the resolver response signals (13, 14) are measured, successive (16) measurements of each response signal are stored into a sample buffer (5), FIR filtering (10) is computed for the response signal values (16) present in the sample buffer (5) at the instant of computation, the computation points (23, 24) and the set of computation result values (18) corresponding to these points are stored in memory, at least two sets of values (18, 19) of computation results are compared to each other and of these the value set Amax (19) which contains the highest computation result as an unsigned value is selected, and FIR filtering (10) is repeatedly computed at the computation points (25, 26) corresponding to value set Amax (19).