Components electric motors

The electric motors are often the noisiest component of the centrifuge assembly. Most standard motors in the 75—250 kW range develop noise levels of 85 dbA (weighted sound pressure level using filter A, per the ANSI standard). A quiet motor can reduce this level by 5 dbA and should be used whenever noise is of concern. 

Collection and analysis of vibration signatures is a complex procedure. By looking at a vibration spectrum, one can identify which components of the pump system are responsible for a particular frequency component. Comparison of vibration signatures at periodic intervals reveals if a particular component is deteriorating. The following example illustrates evaluation of the frequency composition of an electric motor gear pump system. 

Air-cooled heat exchangers include a tube bundle, which generally has spiral-wound fins upon the tubes, and a fan, which moves air across the tubes and is provided with a driver. Electric motors are the most commonly usea drivers typical drive arrangements require a V belt or a direc t right-angle gear. A plenum and structural supports are basic components. Louvers are often used ... 

The speed of an electric motor can be changed by altering the frequency of the electric current. This is because the ratio is the same as 60 or 50 f/p (f = the frequency of the current, p = the number of poles in the stator). Frequency converters are built of electronic components, frequently combined with microprocessors. They provide good motor protection and are superior to the traditional bimetal protection. The characteristic curve for a pump and fan motor is also quadratic, making lower demands to the frequency converters When the frequency of the electrical current is changed in the frequency converter, the main AC supply is transformed into DC. The DC is then treated... 

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 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). 

Even when the time comes to make a purchasing decision, an energy-efficient motor purchase is not a certainty. Sometimes an energy-efficient motor will be the economically efficient choice at other times, not. The capital investment decision is based on the cost in relation to performance, efficiency and reliability. Moreover, the decision depends on the application and the amount of time the motor is in operation. It can be the major component of a product (drill or mixer), or a minor component (computer disk drive) it can be the major component cost of a product (fan), or it can be a minor component cost (stereo tape deck) it can run almost constantly (fan, pump, and machinery), or only a few minutes a day (vacuums and power tools). For example, contractors purchase circular saws almost solely based on performance and reliability. Time is money, and since the saw is operating only a few minutes a day and the contractor is often not responsible for the electricity costs to run the motor, energy efficiency is not a consideration performance and reliability are what matter most. On the other hand, an industrial user, who runs huge electric motors twenty-four hours a day to work pumps, machinery, and ventilation equipment, is very concerned tvitli energy efficiency as well as performance and reliability. 

Machine components The EIS should provide information on all components (e.g., bearings, gears, gearboxes, electric motors, pumps, etc.) that make up the machine-train. Since these components generate vibration energy and unique frequency components, this information is essential for proper analysis. At a minimum, the information sheet must include detailed bearing information, passing frequencies, and nameplate data. 

Measurement locations should be permanently marked to ensure repeatability of data. If transducers are permanently mounted, the location can be marked with a center punch, paint, or any other method that identifies the point. The following sections give the recommended locations and orientations of measurement points for the following common machines or machine components compressors, electric motors, fans and blowers, gearboxes, process rolls, and pumps. 

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. 

In recent years, a minor component of the atmosphere, ozone, has received a great deal of attention. Ozone, molecular formula O3, is a pale blue gas with a characteristic odor that can be detected after lightning activity, in the vicinity of electric motors, or near a subway train. 

We are able to construct mechanical arms that reproduce movements quite close to those performed by the human arm. The problem in implanting these arms is that movements have to be coordinated with all the other body movements under the brain s direction. There is one possibility for connecting the electronic systems of the artificial arm to the nervous signals (Fig. 33) coming from the brain in order to obtain coordinated movements separate those signals into different components and amplify every component to drive an artificial muscle or electric motor. 

In active wheel system, active wheel is equipped with wheel, tire, electric motors, and other electromechanical components and connections all packed within the circumferences of the wheel and tire. Electric motor not only mns the wheels but also slows and stops them as a result, traditional disk or drum brakes might eventually be eliminated. By using electric motors to turn the wheels, large heavy transmission and differential become obsolete (Figure 32.11). 

For the designer, the use of a standardised component size allows for the easy integration of a piece of equipment into the rest of the plant. For example, if a standard range of centrifugal pumps is specified the pump dimensions will be known, and this facilitates the design of the foundations plates, pipe connections and the selection of the drive motors standard electric motors would be used. 

Beneath the passenger cabin is an 11-inch-thick aluminum frame that holds all of the electric motors, microprocessors, mechanical parts, fuelcell components, hydrogen tanks and other systems needed to operate the vehicle. The control wiring is carried in a single harness and permits designers to locate the operating controls virtually anywhere in the wide-open interior. 

In Ballard s alliance with Ford, Volvo, and Daimler Chrysler, they will supply the other components of the vehicles from the car body to the electric motor drive. The fuel cell will function as the car s engine. It needs cooling, control and fuel processing. 

Whereas the drive train of the standard combustion engine comprises many individual, diverse components, these are reduced in fuel-cell propulsion systems to a few expensive components. The decision on the production location of the important system components (i.e., fuel-cell stack, hydrogen storage, reformer and electric motor) will, therefore, be vital for the regional supplier structure. 

Weekly inspection and testing consists of visual inspection of oil and fuel levels and fire pump components, including the controller. A function test of the fire pump, driver and starting systems should be conducted. The fire pump should run for a minimum of 10 minutes for electric motor drivers and 30 minutes for other drivers. 

In the following section constructural details of the Sequenator will be described to the extent required for an understanding of its operation. A detailed technical description has been published in 1967 by Edman and Begg ). Fig. 3 represents a diagrammatic view of the essential components of the instrument. The central part of the Sequenator is the reaction vessel (A), a cylindrical cup of pyrex glass mounted on the shaft of an electric motor (5). Correct functioning of this device requires that the inside cylindrical surface of the cup runs absolutely true. Variance would cause untolerable turbulence within the liquid film spread on the wall of the cup. An additional requirement is constant rotational speed of the cup. Variance of the speed would cause movement of the film up or down the wall. The cup is housed in a bell jar Q) which... 

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