Effects of specification requirements on induction machine design and operation

摘要

User specifications and industry standard requirements determine the size of a motor and its mechanical and electrical performance characteristics. There are occasions where these specification requirements conflict with one another, cause an unfavorable design characteristic, are unclear, or in some cases, do not reflect the exact site conditions. This paper is multi-purpose. It first identifies the cause and effects of common specification provisions that can effect the ultimate motor design which may not be the desired result from the buyer/owner's perspective. Relationships to power factor, efficiency, inrush current, service factor, temperature rise, insulation, and motor torques are explored. Site specific effects of ambient temperatures, altitude and common power quality issues, such as line dips and bus transfers are also included. Next, accessory peripherals are not always consistent and appropriate for the machine being purchased and some impact maintenance efficiency. Finally, if the original specification requirements did not properly represent the actual site conditions, what can be done to make the motor conform to it's environment is discussed. Case histories of some of the most frequent among these problems along with their successful resolutions are presented.