Study On Permanent-magnet DC Motor Testing System

This paper carries out the research and development on the test andmeasurement methodology for permanent magnetic DC motors, which havebeen in mass product phase. An innovative mathematical modeling algorithm isproposed, which is different from traditional system recognition methods. Theclassic control theory is used to deduce the theoretical model of the DC motor,in order to find the relationship between armature current and some motorphysical parameters such as coefficient of viscosity, moment of inertia androtate speed. This method enables the motor performance analysis by usingminimum set of parameters got from the measurement.At first, the paper summaries the domestic and foreign status of motor testtechnologies and analyzes the gap between the state of the art technologies ofmotor test in the world and the engineering applications in the aerospaceindustry in China, a solution is proposed to improve the test and measurementmethod of DC motors, design of which have been finalized and production ofwhich has been in mass phase in aerospace industry.The paper uses three parts to study the test methods of the model of motor.The first part deeply analyzes the DC motor’s mathematical model, setting upthe theoretical relationship between armature current and some motor physicalparameters. The second part takes use of the model introduced by the first partto modify the existing motor test method. This new method doesn’t disruptivelychange the well-accepted motor test philosophy but improves the current androtate speed measurement methods. Replacing the simple and inaccurate devices,the system picks the new current sensor and speed sensor. The mechanicalperformance of motor has been achieved by using the theory deduced by partone. So the test is comprehensive and simplified. Two types of current sensorshave been explored in the experiential work separately: Hall current sensor andMAX471current sensor. By comparison of the experiential results MAX471current sensor has been chosen as the device for the final solution and aphotoelectric encoder is used to measure the rotate speed. The third part focuseson motor performance measurement during its running attrition test, which is an innovative method. Today there is no measurement and control during motor’srunning attrition test. When multiple motors under simultaneous runningattrition test without loads, the armature current is the only parameter to teston-line and a method is proposed to achieve the key motor parameters such asrotate speed, electric potential and torque coefficient.The improved test method for the permanent motor is implemented, whichis not only a solution for current monitoring during the motor running attritiontest, but also a simplified measurement method of DC motor modeling. By usingthe minimum physical parameter measurement, the on-line test has beenachieved, which is a highly efficient method of motor data collection,manipulation, process, calculation and report generation. The improved methodcan not only increase the productivity and quality dramatically, but also ensurethe final quality of the motors when delivered from the product line. In addition,the method also provides the theoretical and hardware foundation for the in-linetest of the magnetic powder clutch electric servo system. So this research anddevelopment has a great significance for the further improvement of this servosystem test method.