Rolling bearings and seals in electric motors and generators

® SKF, @PTITUDE, BAKER, CARB, DUOFLEX, DURATEMP, ICOS, INSOCOAT, MARLIN, MICROLOG, MONOFLEX, MULTILOG, SEAL JET, SKF EXPLORER, SYSTEM 24 and WAVE are registered trademarks of the SKF Group. © SKF Group 2013 The contents of this publication are the copyright of the publisher and may not be reproduced (even extracts) unless permission is granted. Every care has been taken to ensure the accuracy of the information contained in this publication but no liability can be accepted for any loss or damage whether direct, indirect or consequential arising out of the use of the information contained herein....

1 Rolling bearings in electric machines 1 3 Seals in electric machines 3 6 Bearing mounting, dismounting and motor testing 6 7 Bearing damage and corrective actions 7

Rolling bearings and seals in electric motors and generators A handbook for the industrial designer and end-user

Foreword This SKF applications, lubrication and maintenance handbook for bearings and seals in electric motors and generators has been developed with various industry specialists in mind. For designers of electric machines1), this handbook provides the information needed to optimize a variety of bearing arrangements. For specialists working in various industries using electric machines, there are recommendations on how to maximize bearing service life from appropriate mounting, maintenance and lubrication. The recommendations are based on experience gained by SKF during decades of close cooperation...

Contents SKF – the knowledge engineering company . . . . . . . . . . . . . . . . . . . . . . . . . . . Our knowledge – your success . . . . . . . . . . . . . . . . . . . . . . . . Seals in electric machines . . . . . . . . . . . Design requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Integral bearing seals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shaft seals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Special seals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rolling bearings in electric...

Bearing mounting, dismounting and motor testing . . . . . . . . . . . . . . . . . SKF Engineering Consultancy Services . . . . . . . . . . . . . . . . . 126 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mounting methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SKF calculation tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 Application specific solutions . . . . . . . . . . . . . . . . . . . . . . . . . 128 Dismounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 Condition...

SKF – the knowledge engineering company From one simple but inspired solution to a misalignment problem in a textile mill in Sweden, and fifteen employees in 1907, SKF has grown to become a global industrial knowledge leader. Over the years we have built on our expertise in bearings, extending it to seals, mechatronics, services and lubrication systems. Our knowledge network includes 46 000 employees, 15 000 distributor partners, offices in more than 130 countries, and a growing number of SKF Solution Factory sites around the world. Research and development We have hands-on experience in over...

Working closely with you Our objective is to help our customers improve productivity, minimize maintenance, achieve higher energy and resource efficiency, and optimize designs for long service life and reliability. Innovative solutions Whether the application is linear or rotary or a combination of the two, SKF engineers can work with you at each stage of the asset life cycle to improve machine performance by looking at the entire application. This approach doesn’t just focus on individual components like bearings or seals. It looks at the whole application to see how each component interacts...

Rolling bearings in electric machines Design requirements . . . . . . . . . Bearing selection . . . . . . . . . . . . Calculation example . . . . . . . . . . Deep groove ball bearings . . . . . Cylindrical roller bearings . . . . . INSOCOAT bearings . . . . . . . . . . Hybrid bearings . . . . . . . . . . . . . Angular contact ball bearings . . Spherical roller bearings . . . . . . CARB toroidal roller bearings . . Spherical roller thrust bearings

Rolling bearings in electric machines The purpose of using rolling bearings in electric machines is to support and locate the rotor, to keep the air gap small and consistent and to transfer loads from the shaft to the motor frame. The bearings should enable high and low speed operations, minimize friction, and save power. The designer has to consider many different parameters when selecting the bearing type and arrangement to meet the requirements of any particular motor application. Under all circumstances, the design should be economical from both a manufacturing and a maintenance perspective....

1 Rolling bearings in electric machines Design requirements Dimensions In most cases, power output determines shaft size, and shaft size determines the bore diameter of the bearings. In recent years, the tendency has been to use bearings with smaller cross sections because they require less space. loads only while other bearings, such as angular contact ball bearings, are better suited for combined loads. In order to provide satisfactory operation, ball and roller bearings must always be subjected to a given minimum load. Refer to the relevant bearing type in the table section of the SKF Rolling...

1 Rolling bearings in electric machines Design requirements Table 1 Design considerations and operating conditions • Boundary dimensions • Magnitude and direction of loads • Speed: fixed, variable or high • Shaft and housing materials • Coupling, belt or gear drive • Horizontal or vertical mounting • Environment • Vibration level • Noise level • Temperature • Required bearing life • Lubrication: grease versus oil • Maintenance • Condition monitoring • Sealing (integral and/or external) • Product availability • Required precision • Handling and transportation • Mounting tools Important parameters...