SAFETY ARRANGEMENT OF AN ELEVATOR

The invention relates to a safety arrangement of an elevator, which comprises sensors (27, 28) configured to indicate functions that are critical from the viewpoint of the safety of the elevator, and also a safety circuit (20, 34). With which the data formed by the aforementioned sensors (27, 28) indicating the safety of the elevator is read. The safety arrangement comprises a drive device (1) for driving the hoisting machine of the elevator. The drive device (1) comprises a DC bus (2A, 2B), and also a motor bridge (3) connected to the DC bus for the electricity supply of the elevator motor (6). The motor bridge (3) comprises high-side (4A) and low-side (4B) switches for supplying electric power from the DC bus (2A, 2B) to the elevator motor (6) when driving with the elevator motor (6), and also form the elevator motor (6) to the DC bus (2A, 2B) when braking with the elevator motor (6). The drive device also comprises a control circuit (5) of the motor bridge, with which control circuit the operation of the motor bridge (3) is controlled by producing control pulses in the control poles of the high-side (4A) and low-side (4B) switches of the motor bridge, an input circuit (12) for a safety signal (13), which safety signal (13) can be disconnected/connected from outside the drive device (1), and also drive prevention logic (15), which is connected to the input circuit (12) and is configured to prevent the passage of control pulses to the control poles of the high-side (4A) and/or low-side (4B) switches of the motor bridge when the safety signal (13) is disconnected. The signal conductor of the safety signal (13) is wired from the safety signal (20, 34) to the drive device (1), and the safety circuit (13). The safety circuit (20, 34) is arranged to bring the elevator into a state preventing a run disconnecting the safety signal (13), and the safety circuit (20, 34) is arranged to remove the state preventing a run by connecting the safety signal (13). FIG. 1