Transient Processes Analysis in Electromagnetic Machines with Electric Impulse Control

The paper is concerned with design and performance features of electromagnetic machines with permanent magnets. Graphic-analytical calculation method was described for transient processes taking place during magnification and demagnetization of the operating solenoid magnetic structure in electromagnetic machines with electric impulse control where the power is supplied to the operating solenoid winding briefly only at the moments when the solenoid armature moves from one end position to the other one. By passing the current of certain polarity, one can provide magnification of the permanent magnet whose magnetic field keeps the armature in the required position after the power supply is switched off. To move the armature to the other position, the current of different polarity is passed briefly through the winding and the whole system gets demagnetized. To calculate the response speed parameter of moving the armature from one end position to the other one, an engineering method was proposed. The method consists in such transformation of the initial differential equation wherein the current time corresponding to the current magnetic flow value is calculated by graphical plotting. As the method uses the actual magnetization characteristic of the permanent magnet, it can provide sufficiently high accuracy. Taking into account the magnetic flow change law, one can calculate the law of compressive force build-up for friction elements and, consequently, calculate electromagnetic machine response speed parameter.