Method for operating a lift system

A method for operating a lift system having a lift cage movably housed inside a lift shaft and a linear drive configured to drive the lift cage, wherein the linear drive includes,

• a stator arrangement fixedly attached to the lift shaft with a plurality of stators, the stator arrangement comprising a plurality of electromagnetic coils each configured to be operated by one phase of a polyphase alternating current, and
• a rotor attached to the lift cage,
• the method comprising:
• providing the polyphase alternating current to operate the stator arrangement and thereby drive the lift cage to generate an upward drive force for the lift cage;
• monitoring a deceleration value of the lift system with sensors that are permanently installed in the lift shaft by,
• measuring the progress of a phase angle of the polyphase alternating current, and
• calculating a deceleration of the phase angle therefrom;
• and
• switching the linear drive into a safety operating state when the deceleration value above a predefined threshold value is determined by way of said monitoring.

A method for operating a lift system having a lift cage movably housed inside a lift shaft and a linear drive configured to drive the lift cage, wherein the linear drive includes,

• a stator arrangement fixedly attached to the lift shaft with a plurality of stators, the stator arrangement comprising a plurality of electromagnetic coils each configured to be operated by one phase of a polyphase alternating current, and
• a rotor attached to the lift cage,
• the method comprising:
• providing the polyphase alternating current to operate the stator arrangement and thereby drive the lift cage to generate an upward drive force for the lift cage;
• monitoring a deceleration value of the lift system with sensors permanently installed in the lift shaft, wherein the sensors are current measuring instruments that measure the phases of the polyphase alternating current that correlate to the deceleration value of the lift system;
• and
• switching the linear drive into a safety operating state when the deceleration value above a predefined threshold value is determined by way of said monitoring.