Abstract:
A method for performing an emergency stop with an elevator and a safety arrangement of an elevator are disclosed. In the method, when an emergency stop criterion is fulfilled, the elevator car is driven with the electric motor of the hoisting machine to a stop with a given deceleration profile.
Abstract:
A safety arrangement of an elevator and a method for monitoring electrical safety in an elevator system is disclosed. The safety arrangement of an elevator includes a motor drive of the elevator, which motor drive includes a main circuit, an accessible conducting part, which is earthed, an insulator, which is adapted to electrically insulate the aforementioned conducting part from the aforementioned main circuit and also a monitoring circuit, which is configured to determine an earth fault of the aforementioned main circuit occurring via the aforementioned conducting part. The monitoring circuit is configured to form a signal indicating the danger of electric shock in the motor drive of the elevator, if the aforementioned earth fault is diagnosed.
Abstract:
A drive system for driving an electric motor includes a drive control unit and a frequency converter including a speed controller. The drive control unit is configured to: define a speed reference of the electric motor; preset operating parameters of the speed controller to provide a first response time of the speed controller, before a drive of the electric motor is initiated; adjust at least one operating parameter of the speed controller to provide a second response time of the speed controller, after the speed of the electric motor reaches a constant speed, wherein the second response time is slower than the first response time; and readjust the at least one operating parameter of the speed controller to provide the first response time, before a deceleration from the constant speed is initiated. A method is disclosed for controlling the drive system for driving the electric motor.
Abstract:
An electrical converter unit and a method for reducing thermal stress of a power semiconductor switch, such as an IGBT, of an electrical converter unit, the electrical converter unit comprising at least a gate control circuit wherein the electrical converter unit controls an electrical motor. The method comprises determining load and estimating required motor current based on the determined load and/or a predetermined speed profile. The electrical converter unit has at least a first operating state and a second operating state. The second operating state is used if predetermined criteria is fulfilled, the predetermined criteria relating to at least one of the following: estimated required current, measured motor speed, temperature of the power semiconductor switch and/or electrical converter unit, temperature model of the power semiconductor switch and/or electrical converter unit. In the second operating state a lower switching frequency of the power semiconductor switch is used than in the first operating state, and in the second operating state a higher switching speed of the power semiconductor switch is used than in the first operating state.
Abstract:
A method for testing an elevator hoisting machine brake with a preselected test load TL includes confirming empty elevator car positioned at a test location stest; obtaining information of elevator balancing B; obtaining information of friction Fr of the elevator at the test location stest; determining required assisting test torque TM of a hoisting machine motor based on said test load TL, balancing B and friction Fr; opening one of the brakes while keeping rest of the brakes engaged in braking position, applying torque with the motor at most up to the required test torque TM, measuring movement of the elevator car, and if movement of the elevator car was detected, generating a signal indicating degraded condition of one or more hoisting machine brakes.
Abstract:
A method for controlling an elevator includes controlling the speed of a vertically moving elevator car during its run from a starting landing to a destination landing according to speed settings, the speed settings defining a constant target speed for the elevator car. The method includes obtaining measurement data of the ongoing run, which measurement data describes vertical speed and/or vertical acceleration of the vertically moving elevator car, determining whether the measurement data meets one or more predetermined criteria indicating unintended vertical speed and/or unintended vertical acceleration, and changing the speed settings of the current run by lowering the constant target speed from a first constant target speed to a second constant target speed if the measurement data meets said one or more predetermined criteria, continuing the run without intermediate stops to said destination landing. An elevator is provided to implement the method.
Abstract:
An elevator includes a control system for monitoring the load of a car, which control system is adapted to prevent the normal starting of the elevator, optionally also including relevelling, when there is an overload in the car. The elevator includes at least one position measuring device, speed measuring device and/or movement measuring device in order to determine the movement and/or position of the car, and the control system of the elevator is adapted to remove the prevention of normal starting when at least one said position measuring device, speed measuring device and/or movement measuring device detects that the car moved or is moving upwards in the elevator shaft. In the method, the control system of the elevator is used to determine the load situation of the car, including both the steps to prevent the normal starting of the elevator, optionally also including relevelling, when there is an overload in the car and to open some of the machinery brakes and to keep the remaining machinery brakes closed in order to determine the load situation.
Abstract:
A safety arrangement of an elevator and a method for monitoring electrical safety in an elevator system is disclosed. The safety arrangement of an elevator includes a motor drive having a main circuit, an accessible conducting part, which is earthed, an insulator, which is adapted to electrically insulate the aforementioned conducting part from the aforementioned main circuit and also a monitoring circuit, which determines an earth fault of the aforementioned main circuit occurring via the conducting part. The monitoring circuit forms a signal indicating the danger of electric shock in the motor drive of the elevator, if the earth fault is diagnosed.
Abstract:
Brake release sensors for an elevator can be replaced by an arrangement wherein the brake release is determined from the force caused by the brake. This is achieved by providing measuring device for measuring the weight of an elevator car between the brake and the motor body so that the weight of the elevator car is measured only when the brake is on.