Facebook Twitter LinkedIn YouTube Menu Search Arrow Right Arrow Left Arrow Down Arrow Up Home Arrow Next Arrow Previous RSS Icon Calendar Icon Warning Icon
Proper Repair/Rewind Practices Maintain Efficiency/Reliability of Premium Efficiency/IE3 Motors  DOWNLOAD THE EXECUTIVE SUMMARY
DISCOUNTED WEBINAR RECORDING BUNDLES AVAILABLE LEARN MORE

Filter the results

  • Enter one or more words to find resources containing any of the words entered
  • Enter words or phrases between " " to find exact match

EASA website guide

Download a helpful guide to resources on the EASA website.

DOWNLOAD

Resource Library

Article

Electric motor basics: Why are rotors skewed?

  • December 2003
  • Number of views: 531
  • Article rating: 5.0

Cyndi Nyberg 
Former EASA Technical Support Specialist 

Stator windings in three-phase motors are de­signed to have the amount of flux that the core needs to produce the desired output. The number of turns and size of wire are limited by the core dimensions. However, in the squirrel cage rotor, there are many more variables in the design. One of the variables is the shape of the rotor slot. Many rotor designs are skewed. So, why are ro­tors skewed? 

As the rotor turns, discontinuities on the sur­face of the rotor and stator disrupt the magnetic flux path of the motor. The flux path variation shows up in the form of harmonics that affect the performance of the motor. The difference be­tween the number of stator slots and rotor slots has a significant impact on the harmonics. The motor may be noisy, or there may be stray torques that lower the torque during starting or acceleration. The stator-rotor slot difference is why a motor winding that is redesigned for a dif­ferent speed may have problems, and why it is important to check the stator-slot-rotor-bar com­bination before proceeding with the redesign. 

LOGIN TO VIEW AND DOWNLOAD THE ARTICLE



Rate this article:
5.0
Print


PREVIOUS ITEM

Comments are only visible to subscribers.

Getting The Most From Your Electric Motors

Getting The Most From Your Electric Motors - coverThis 40-page booklet provides a great marketing tool for your service center! Use it to provide end users with information that will help them obtain the longest, most efficient and cost-effective operation from general and definite purpose electric motors.

This booklet covers topics such as:

  • Installation, startup and baseline information
  • Operational monitoring and maintenance
  • Motor and baseline installation data
  • How to read a motor nameplate
  • Motor storage recommendations

LEARN MORE AND DOWNLOAD MÁS INFORMACIÓN Y DESCARGAR

READ MORE ABOUT THE FEATURES AND BENEFITS

EASA Technical Manual

EASA Technical Manual cover

The EASA Technical Manual is the association's definitive and most complete publication. It's available FREE to members in an online format. Members can also download PDFs of the entire manual or individual sections.

VIEW & DOWNLOAD

ANSI/EASA AR100-2015

ANSI/EASA AR100-2015 cover

Recommended Practice for the Repair of Rotating Electrical Apparatus
This is a must-have guide to the repair of rotating electrical machines. Its purpose is to establish recommended practices in each step of the rotating electrical apparatus rewinding and rebuilding processes.

DOWNLOAD - ENGLISH

DESCARGAR - ESPAÑOL

EASA AR200

EASA AR200: Guide for the Repair of Power and Distribution Transformers cover

Guide for the Repair of Power and Distribution Transformers
This document establishes guidelines for each step of the repair of power transformers, describing record keeping, tests, analysis, and general guidelines for the repair of power transformers.

LEARN MORE