Electric Motors: Repair or Replace? Sales/Marketing PowerPoint Tool-EASA Document

EASA Document
Pdf Summary
The "Good Practice Guide to Maintain Motor Efficiency" outlines methods for service center technicians and motor winders to uphold or enhance the efficiency, reliability, and quality of motors during repair and rewinding processes. Drawing from the 2019 and 2003 EASA and AEMT rewind studies and earlier research, the guide is applicable to all three-phase induction motors.<br /><br />Key sections of the guide include:<br /><br />1. <strong>Energy Losses in Induction Motors</strong>:<br />   - Identifying five types of losses: core (iron) losses, stator I2R losses, rotor losses, friction and windage losses, and stray load losses.<br />   - Highlighting the variability of losses with motor load and the potential increase when motors run on variable-frequency inverters.<br /><br />2. <strong>Motor Repair Processes</strong>:<br />   - <strong>Preliminary Inspection</strong>: Gathering motor nameplate data, conducting external inspections, and consulting customer input.<br />   - <strong>Dismantling the Motor</strong>: Detailed steps for safely removing components and ensuring accurate reassembly.<br />   - <strong>Removing the Old Winding and Cleaning the Core</strong>: Includes core loss testing before and after burnout, and procedures to avoid damaging laminations during coil removal.<br /><br />3. <strong>Rewinding the Motor</strong>:<br />   - <strong>Duplicate Rewinding</strong>: Steps to copy the manufacturer’s original winding while minimizing coil extension length and maximizing copper cross-sectional area.<br />   - <strong>Changing to a Two-layer Lap Winding</strong>: Guidelines for redesigning windings to ensure efficiency while simplifying the winding process.<br /><br />4. <strong>Mechanical Repairs Affecting Motor Efficiency</strong>:<br />   - Importance of accurate mechanical repairs, including shaft, housing, bearing, and fan repairs to maintain efficiency.<br /><br />5. <strong>Reassembling the Motor</strong>:<br />   - Ensuring bearings, fans, and air baffles are correctly installed and maintaining proper lubrication.<br /><br />6. <strong>Confirming Repair Quality</strong>:<br />   - Load testing is not always practical, so verifying core loss tests and resistance measurements can ensure the repair has not adversely affected motor efficiency.<br /><br />The guide emphasizes standard practices, testing procedures (such as phase balance and hipot tests), and careful documentation to ensure motor efficiency. It also provides tips for handling specific issues related to core preparation, coil insertion, and varnish application. With detailed instructions and illustrations, technicians can achieve high-quality repairs that sustain or improve motor performance.
Keywords
Motor Efficiency
Service Center Technicians
Motor Winders
Induction Motors
Energy Losses
Motor Repair Processes
Rewinding
Mechanical Repairs
Reassembling Motor
Repair Quality