Converter to control an electric hoisting motor

摘要

A command input device (8) is provided for specifying the speed of the motor. A control device measures the torque and speed of the motor and based on these measurements sets the limit speed of the motor to ensure that the maximum power is not exceeded. The control device makes sequential measurements of the torque if the set speed is above the nominal speed and sets a new limit speed if the variations in the torque over two sequential measurements exceed a preset threshold. An assembly consisting of a control system, a motor and an electromagnetic brake is also claimed.