Improving reliability of drill rig electric drive control system

The article deals with the control system for the electric drives of drilling winches and rotors based on a programmable logic controller and thyristor converters. The block diagram of the controller is described. The shortcomings of the existing control system associated with the failure of the controller module are revealed. The failure statistics of the controller modules for 2014-2015 is given. The application of a functional circuit for rotation speed generating by using an analog signal in a thyristor converter control system and a device for switching the analog input signals of a controller are suggested. The device allows automatically switching the analog input signals of the controller when the input analogue signal module fails. It is shown that the proposed device has made it possible to reduce the unproductive time of drilling crews.