MASTERING PREDICTIVE MAINTENANCE - Static and Dynamic Motor Testing as Part of a Predictive - Maintenance Program

摘要

Motors are a part of a "system" which includes the incoming power, the load and, of course, the motor itself. Maintaining the safe and profitable operation of plants and facilities, demands a high degree of motor reliability. The power generation industry ranks at the top of this requirement for uninterrupted operation and safe, continued production. This paper seeks to present the most current, effective and widely accepted methods of electrically testing and trending the operational health of electric motors. The benefits and features of various modern electrical test equipment and testing methodologies will also be discussed. Predictive maintenance programs are only effective when all available means of measuring and trending the condition of electric motors, cables and switch gear are utilized. Modern test equipment exist to both simulate "real-world" situations in static testing and acquire safe and complete dynamic data in the motor's natural environment. Static data helps define the motor's insulation integrity and modern equipment is capable of aiding technicians in predicting imminent failures before they become catastrophic. Effective static test equipment is capable of testing the components of motors at voltage levels similar to those the motor will see in its normal operation without destructive currents. Static testing should include the surge test which is the most effective method of insuring the integrity of the copper-to-copper insulation. Modern test equipment will provide trending logs and reports allowing technicians to track the decline in the motors health. State-of-the-art dynamic test equipment can locate power related issues and load problems as well as motor condition problems. The most modern of equipment can calculate speed and torque, define rotor bar problems and measure distortion. Dynamic testing of electric motors is a relatively new field that has huge potential and is growing rapidly. Numerous mechanical issues are being identified including bearing problems, mechanical looseness and many other concerns. Dynamic testing will help separate mechanical from electrical issues and provides extensive information regarding the rootcause of motor failures. An effective Predictive Maintenance Program must include both static and dynamic motor testing if the program is to be successful. Each defines specific areas of concern regarding the motor system, each has its limitations, and each lends support to the other.