In electric motors and

General problems in electric motors and their remedy 10/239... 

Installation of bearings and pulleys Important checks at the time of commissioning Maintenance of electric motors and their checks Maintenance of bearings General problems in electric motors and their remedy Winding temperature measurement at site Analysis of insulation failures of an HT motor at a thermal power station... 

Space heaters, particularly in electrical motors and generators which may be idle for significant periods of time, can also help prevent the accumulation of moisture. Space heaters installed in classified areas must operate at temperatures below high temperature devices. 

Molding powders are B-stage silicone resin plus glass fiber and catalyst. They are compression molded 5 to 20 min at 1000 to 4000 psi and 160°C and then post-cured several hours to achieve optimum properties. Electrical insulation and resistance to heat and moisture are outstanding (Table 3.44). Molded parts are used in electric motors and switches. 

Low carbon steels are the most widespread magnetic metallic materials for use in electric motors and inductive components such as transformers, chokes, and a variety of other AC applications which require high magnetic induction at moderate to low losses. This is mainly due to the high intrinsic saturation polarization of the base element Fe, /s = 2.15 T, and to the low cost of mass produced steels. 

The elements Mn and Si are added to steel to improve its properties in electric motors, and some C is often found as a detrimental impurity. Which of these elements fills interstitial holes in the Fe lattice and which substitutes for the Fe in the lattice ... 

Close-Coupled Pumps (Fig. 10-38) Pumps equipped with a built-in electric motor or sometimes steam-turbine-driven (i.e., with pump impeller and driver on the same shaft) are known as close-coupled pumps. Such units are extremely compact and are suitable for a variety of services for which standard iron and bronze materials are satisfactory. They are available in capacities up to about 450 mVh (2000 gal/min) for heads up to about 73 m (240 ft). Two-stage units in the smaller sizes are available for heads to around 150 m (500 ft). 

Steady transmitted torque. Smooth nonfluctuating torque in electric motors, turbines, and a variety of smooth torque-absorbing load (driven) machines. 

The driver on centrifugal compressors should be correlated separately. The difference in the initial cost of an electric motor and gas turbine would overshadow the cost correlation of compressors. Literature data can be found in Reference 25. 

Silicone laminates are used principally in electrical applications such as slot wedges in electric motors, particularly class H motors, terminal boards, printed curcuit boards and transformer formers. There is also some application in aircraft, including use in firewalls and ducts. 

Determination of Reliability Characteristic Factors in the Nuclear Power Plant Biblis B, Gesellschaft fur Reaktorsicherheit mbH Nuclear Failure rates with upper and lower bounds and maintenance data for 17,000 components from 37 safety systems Data for pumps, valves, and electrical positioning devices, electric motors and drives from an operating power plant 66. 

This data collection effort was concentrated on the following components because of their extensive populations and repair action documentation pumps, valves, electrical positioning devices, electric motors, and drives. For each component type, preface pages and data summary tables are provided. Separate data summary tables are provided for each component type and are structured in a format that allows for the inclusion of the number of pieces of operating equipment, the total number of operating hours, total number of failures, and hourly failure rates with upper and lower bounds. 

This report provides an aging assessment of electric motors and was conducted under the auspices of the USNRC NPAR. Pertinent failure-related information was derived from LERs, IPRDS, NPRDS, and NPE including failure modes, mechanisms, and causes for motor problems. In addition, motor design and materials of construction were reviewed to identify age-sensitive components. The study included consideration of the seismic susceptibility of age-degraded motor components to externally-induced vibrational effects. 

The early development of electric motors and generators can be traced to the 1820 discovery by Hans Christian Oersted that electricity in motion generates a magnetic field. Oersted proved the long-suspected... 

As electricity became more widely available in the early 1900s, and as gasoline became readily available as a fuel for automobiles, electric motors and gasoline engines began to replace Stirling engines. 

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