Maintenance electric motors

Within these basic principles there are many types of electric motors. Each has its own individual operating characteristics peculiarly suited to specific drive applications. Equations (29-1) through (29-9), presented in Table 29-1, describe the general operating characteristics of alternating-current motors. When several types are suitable, selection is based on initial installed cost and operating costs (including maintenance and consideration of rehability). 

Maintenance and Reliability Preventive maintenance requires that all engines be shut down at periodic intervals for inspection and repair. For properly maintained heavy-duty engines availability is over 97 percent, with maintenance costs of 2.50 to 5 per horse-power-year and lubricating-oil consumption of 1 to 2 gal/hp-year. While this represents a high degree of reliability, outages of heavy-duty engines are more frequent than those of electric motors or steam turbines. 

One can adopt a suitable procedure of installation, grouting, type of foundation and alignment etc., depending upon the size of motor, the duty it has to perform and the location of the installation (such as hazardous or seismic, etc.). Here we discuss briefly only the important aspects of installation and maintenance of electric motors. 

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... 

Reduced maintenance costs, leading to an overall improvement in system integrity and reliability. Tlie mean-times-between-failure for active magnetic bearings are equal to tliose of an electric motor. 

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. 

The aforementioned reviews and assessments were assimilated to characterize the effect of dielectric, rotational, and mechanical hazards on motor performance and operational readiness. Functional indicators were identified that can be monitored to assess motor component deterioration caused by aging or other accidental stressors. The study also includes a preliminary discussion of current standards and guides, maintenance programs, and research activities pertaining to nuclear power plant safety-related electric motors. Included are motor manufacturer recommendations, responses from repair facilities to a questionnaire, in-service inspection data, expert knowledge, USNRC-IE audit reports, and standards and guides published by the Institute of Electrical and Electronics Engineers (IEEE). 

Squirrel-Cage Motor. This type of motor finds a broader application and a more extensive and general use than any other type of motor. This is because it is, inherently, the simplest type of electric motor and, also, has excellent characteristics and operates essentially at constant speed. It has greater reliability and low maintenance requirements and thus meets a broad range of applications. 

The information on life-cycle costs gained with certain items of plant and equipment need not be true for a similar item in another location, as specific details on operating hours, and maintenance attendance can vary markedly. Also, it may be an auxiliary part (e.g. an electric motor) of a major component. Therefore, it may have an entirely different set of parameters. An important element that must be examined in detail when establishing life-cycle costs of a specific item of plant and equipment is the demand placed on energy resources by them. 

As an example of the importance of process parameters monitoring, consider a process pump that may be critical to plant operation. Vibration-based predictive maintenance will provide the mechanical condition of the pump and infrared imaging will provide the condition of the electric motor and bearings. Neither provides any indication of the operating efficiency of the pump. Therefore, the pump can be operating at less than 50 per cent efficiency and the predictive maintenance program would not detect the problem. 

Electricity production, using hydrothermal steam, 12 529-530 Electricity supply, operation and maintenance of, 10 159 Electric melting, 23 253 Electric motors, 10 149 Electric polarization, in piezoelectric materials, 22 709-710 Electric potential, 9 739 Electric potential difference, exponents of dimensions, 8 585t Electric power. See also Electricity production... 

Electric motor drives are preferred if the power cost is low, since electric packages are less costly than turbine drives, and motors generally have lower maintenance requirements. Turbine drives are preferred if the fuel gas cost is more attractive than the cost of electric power. Turbines can also provide process heat for the pre-treatment system and may, thus, reduce the need for heating equipment. In many installations, gas turbine fuel is provided from flash gas in the main process. 

The hydraulic system consists of oil reservoir, electric motor, hydraulic pump, heat exchange for oil cooling, oil filters, oil level indicator, electric valves and flow distributors. An hydraulic plant which has been properly installed and care has been taken during the start-up phase, should enjoy long life and not need much maintenance. 

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