Search

Electrical motors, how they work

Welcome! This motor book will provide you with a wealth of information about electrical motors, how they work, what they can be used for, and so on. But before we delve into detailed explanations of the world of electrical motors, we should perhaps spare a brief thought for the purpose of these motors.

The motor book
The motor book (on photo: Single phase magnetic Induction motor with exposed rotor and coil)

After all, motors are always designed to carry out specific tasks. As this is a Grundfos publication, it is only natural that we should pay special attention to motors used for pumps – although much of the information contained within these pages will benefit all those with an interest in electrical motors.


Standards for AC motors

IEC 60034-2 Efficiency standards

Several standards for testing electric machinery exist on a worldwide basis. For induction motors, the three most important ones are IEEE Standard 112, JEC 37 (Japan) and IEC 60034-2. The efficiency value obtained from the different testing standards can differ by several percent.

This seems in contradiction with the theoretical definition of the efficiency:

  • η = power out / power in
  • η = 1 – overall losses / power in

The losses in an induction motor are distributed as follows:

  1. Stator winding loss Pcu1 – approximately 40-45%
  2. Rotor winding loss – Pcu2 – approximately 15%
  3. Friction loss Pfric – approximately 10-15%
  4. Iron loss Pfe – approximately20%
  5. Stray loss Pstray – approximately 10%
Loss distribution in an induction motor
Loss distribution in an induction motor

The main difference between the standards is the way in which the fifth loss component stray loss (Pstray), the additional load losses, is treated.


Standards for the testing of motors

The testing of standard motors is described in IEC 60034-2. In the following paragraphs two different methods of testing motors are presented: The direct method and the indirect one .

The difference between these two methods is the way in which the motor efficiency is established.

IEC 60034 covers the so-called industrial motors . Requirements of domestic appliances are listed in IEC 60335, which specifies somewhat different (stricter) requirements of the motors . In addition to the tests of standard motors our laboratory also undertakes to test products integrating motor and pump .

In principle the thermal tests are the same, but the tests are carried out according to other standards . Small circulator pumps are for instance tested according to IEC 60335-2-51.

Title:Motor Book – Grundfos
Format:PDF
Size:16.57 MB
Pages:252
Download:Right here | Get Download Updates | Get Technical articles
Motor Book - Grundfos
Motor Book – Grundfos

SEARCH: Articles, software & guides

Premium Membership

Premium membership gives you an access to specialized technical articles and extra premium content (electrical guides and software).
Get Premium Now ⚡

Page edited by E.C. (Google).

8 Comments


  1. sandeep
    Jun 01, 2017

    Thank you for EEP,


  2. katakwar
    Aug 20, 2015

    Thank you very much EEP.


  3. Mark E
    Jun 29, 2015

    Thanks for providing an excellent website. I want to download the book on motors titled, “Motor Book – Grundfos” but the link is not working. The link is not a PDF file as it should be. Can you please send me this download in my email or fix the link on the download page. I really appreciate your website. It is an excellent resource, and would be even better if those download links worked as intended.


  4. mohammad mahdi share pasand
    Jun 28, 2015

    Dear authors
    I would like to thank you for this useful portal and its helpful contents. wish you good luck. hope you go on.


  5. Andy Walsh
    Jun 09, 2014

    It may be due to my security settings (I don’t know) but I’m unable to to download most of the material on the site.
    Regards,


  6. tawfik ben mussa
    Jun 09, 2014

    excellent informations , useful for students and professional engineers, i only feel sorry for not having these e books earlier, it could save me a lot of time an efforts. Thanks and keep the good work


  7. WANCLIK TADE
    Jun 08, 2014

    I COMPILE ALSO DATA ABOUT APPLICATIONS IN THE ENGINEERING


  8. Ehsan Daryabeigi
    Jun 08, 2014

    Dear Mrs/Mr
    I would like to download a book entitled “Motor Book – Grundfos” from your site. However, it is not possible for me to do that for even others.

Leave a Comment

Tell us what you're thinking... we care about your opinion!