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Resource Library

Webinar recording bundle

AC Motor Electrical Procedures

  • April 2020
  • Number of views: 9481
  • Article rating: No rating
for EASA members


A special discounted collection of 11 webinar recordings focusing on AC motor electrical procedures.

Once purchased, all 11 recordings will be available on your "Downloadable products purchased" page in your online account.

Downloadable recordings in this bundle include:

The Basics: Motor Repair Burnout Procedures
Presented October 2016

  • Interlaminar insulation materials / properties of AC stators
  • Core testing before and after
  • Processing equipment, controls and records

The Basics: The Why and How of Core Testing
Presented October 2016

  • The reasons for performing core testing and why they are important
  • An explanation of the two core testing methods:
  • Loop testing
  • Use of a core tester
  • How to properly perform a core test
  • How to assess the results
  • Stator Core Testing: Know What You Have Before You Wind It

Stator Core Testing: Know What You Have Before You Wind It
Presented April 2017

This presentation covers:

  • The importance of the stator core test 
  • Simple theory to share with technicians and customers 
  • Practical approach for testing small stators demonstrated 
  • Eliminating pen + paper; loop test calculations for any device 
  • Assessing the results

High Potential Testing of AC Windings
Presented December 2019

High-potential testing is routinely used to assess the ground insulation of AC stator windings in-process, after completion of a rewind and post-delivery. This webinar covers:

  • Differences between AC and DC high-potential tests
  • Sizing AC test sets when testing large windings
  • What relevant standards address (and what they don’t)
  • Communicating test requirements to all stakeholders
  • When to test and at what levels
  • How to evaluate results

Target audience: Beneficial for service center managers, supervisors and technicians responsible for high-potential testing.

Squirrel Cage Rotor Testing
Presented October 2014

Determining whether or not a squirrel cage rotor is defective is an issue that is a challenge to every service center as there is often no simple way to determine the integrity of a rotor. The primary focus of this session is to describe many of the available tests that can be utilized in the service center or at the motor installation site. In addition to conventional squirrel cage rotor testing methods such as the growler test, techniques that will also be covered are the use of a core loss tester, high current excitation, and spectrum analysis of vibration.

Target audience: This presentation will be most useful for service center and field technicians with at least 2 years experience, service center supervisors and managers, engineers, or anyone with previous experience dealing with suspected open rotor issues.

Evaluating High No-Load Amps of Three-Phase Motors
Presented December 2011

This presentation focuses on the steps to take before rewinding to avoid the undesirable situation of high no-load motor amps after the rewind.

The presentation covers the following steps that should be performed on every AC stator rewind:

  • Inspect the stator bore and rotor outside diameter for evidence of machining or damage
  • Record the original winding data exactly as found
  • Verify the winding data
  • Test the stator core before and after rewinding removal

Target audience: This is most useful for service center mechanics and winders with any level of experience, and service center supervisors and managers.

Insulation Technology Improvements and the Repair Market
Presented July 2019

Most modern rotating electric machines operate on the same principles their predecessors have for 100+ years. However, improvements in materials technology over that time have allowed for increasingly greater power density in machine design.

There is a natural time lag between OEM technology improvement and repair of equipment containing that technology. This session will explore some of these improvements and their implications for service centers attempting to provide a quality repair.

Target audience: This webinar will be appropriate for service center managers and technicians responsible for rewind activities.

Motor Temperature Rise and Methods to Increase Winding Life
Presented December 2018

This webinar discusses:

  • Temperature rise: Method of detection, Insulation class, Enclosure, and Service Factor
  • Increasing winding life: Insulation class, Cooling system, and Winding redesign

Target audience: This will be most useful for service center engineers, supervisors, managers and owners. The content will also be beneficial for mechanics and winders.

Air Gap: What It Is, What Does It Do, and Why Is It Important?
Presented October 2019

The physical air gap between the rotor or armature and the stator or field frame is complex and plays a critical role in the performance of AC and DC machines. Most repairers do not realize how little they understand about this subject.

This webinar explains the role air gap plays in AC motor performance, how to recognize the symptoms of an uneven air gap, and share corrective measures. For DC machines, this webinar will cover the distinctly different role of the field air gap as opposed to the air gap of the interpoles.

  • Air gap tolerance of AC machines
  • Air gap tolerance of DC fields and interpoles
  • Allowable runout of rotor / armature
  • Recognizing the signs of air gap anomalies
  • Corrective actions

Target audience: This webinar recording is of benefit to managers, supervisors, winders, mechanics and field service personnel.

Troubleshooting AC Generators & Alternators
Presented May 2015

This recording covers theory of operation, inspection, operation and troubleshooting tips for AC generators and alternators. For the supervisor, field service technician or service center personnel, generators can present unique challenges. Topics covered include:

  • Theory of operation
  • Testing tips
  • Stator winding cautions
  • How to interpret the exciter motor connection
  • In-shop and on-site testing methods
  • How to test the voltage regulator
  • How to test a generator without a regulator

Core Repair and Restack Techniques
Presented April 2014

This webinar teaches:

  • How to repair damaged stator cores and how to know when a restack is necessary.
  • There are often cases when repairs can be accomplished without a labor intensive restack.
  • When a restack is required, there are pitfalls to watch out for to avoid problems with geometry, vibration and core losses.

Target audience: This presentation is useful to the supervisor, winder and sales personnel who interact with the end user.



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Getting The Most From Your Electric Motors

Getting The Most From Your Electric Motors - coverThis 40-page booklet provides great advice for obtaining 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



EASA/AEMT Rewind Study

EASA Rewind Study cover

The Effect of Repair/Rewinding on Premium Efficiency/IE3 Motors
Tests prove Premium Efficiency/IE3 Motors can be rewound without degrading efficiency.


ANSI/EASA AR100-2020

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.



EASA Technical Manual

EASA Technical Manual cover

Revised September 2022
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.