Motors specific power

Figure 5.7 Specific motor power versus throughput (b) self-wiping corotating, (c) counterrotating closely intermeshing, and (a) as (b), but with wider gaps and higher speed (after Ref. 8).

In the higher voltage range, SiC transistors as well as Schottky diodes will be important. Specifically, motor drives will be the main application where SiC will become a major player, especially where power conservation is of prime concern for instance, in the drives to the electric motors for fuel-cell vehicles. The future will be very interesting and very bright. 

The rated power density (or specific rated power) is again the most convenient parameter for comparing different battery systems, and is generally quoted in W/kg or W/dm3. The rated power density and rated energy density are both critical factors when assessing batteries for applications such as motor traction where the battery itself has to be transported. 

Compared to impeller torque, motor power consumption is easier to measure wattmeters are inexpensive and can be installed with almost no downtime. However, motor power signal may not be sensitive enough for specific products or processing conditions. Wear and tear of mixer and motor may cause power fluctuations. Moreover, power baseline may shift with load. 

PCp compressor power for a polytropic compression PE electric motor power Pf fan power Pp pump power PT turbine power R gas constant s entropy T absolute temperature v average velocity or specific volume V gas volumetric flow rate W work... 

Notes The same specifications are listed for co- and for counter-rotating fully intermeshing TSE s On a request machines can be furnished with N s 1500 rpm. On a request L/D = 120 can be provided. Motor power in kW. JSW stands for Japan Steel Works, also known (esp. in Japanese patents) as Nippon Steel Works. 

The values for specific pressure u are normally obtained through orthogonal metal-cutting experiments. Specific pressure is related to and correlates well with shear stress r, for a given metal. The unit power is sensitive to material properties (e.g., hardness), rake angle, depth of cut, and feed, whereas is sensitive to material properties only. Specific power can be used to estimate the motor power required to perform a machining operation for a given material. 

By careful process monitoring we can often detect the effects of wear. The process parameters that are affected by wear are meit temperature, output, and motor ioad. As wear progresses, the quality of the extruded product tends to deteriorate. This may manifest itself as discoloration, streaks, discolored specks, holes, etc. ft is very important to monitor the specific energy consumption (SEC) and specific extruder throughput (SET) because changes in these parameters often correiate with wear. SEC is the ratio of motor power divided by the throughput, ft is the mechanical power consumed per unit mass of plastic. The SEC tends to correiate with the melt temperature. The SEC is normally expressed in kWh/kg. A typicai vaiue of the SEC is 0.25 kWh/hr for extrusion of polyoiefins. 

In agreement with previous studies [3, 4], motor power is shown to be linear in both Q and N. Table 1 shows the steady state model parameters Ci, C2 and C3 for this and subsequent set of data obtained using linear data regression analysis method. A different way to describe this model is that the differential specific energies, 9P/9Q and 9P/5N remain constant for all Q/N. 

From equation 60 one can obtain a theoretical power requirement of about 900 kWh/SWU for uranium isotope separation assuming a reasonable operating temperature. A comparison of this number with the specific power requirements of the United States (2433 kWh/SWU) or Eurodif plants (2538 kWh/SWU) indicates that real gaseous diffusion plants have an efficiency of about 37%. This represents not only the barrier efficiency, the value of which has not been reported, but also electrical distribution losses, motor and compressor efficiencies, and frictional losses in the process gas flow. 

All electrical equipment are designed for a specific BIL, as indicated in Tables 11.6, 13.2, 14.1, and 32.1(A) for motors, switchgears and bus systems respectively, and Tables 13.2 and 13.3 for the main power system (line clearances and insulators). If the actual severity of a prospective surge, i.e. its amplitude and/or rise time or both, is expected to be higher than these levels (higher amplitude and lower rise time) the same must be damped to a safe level, with the use of surge arresters, surge capacitors or both as discussed later. 

Textile motors Crane motors Determining the size of motor Sugar centrifuge motors Motors for deep-well pumps Motors for agricultural application Surface-cooled motors Torque motors or actuator motors Vibration and noise level Service factors Motors for hazardous locations Specification of motors for Zone 0 locations Specification of motors for Zone I locations Motors for Zone 2 locations Motors for mines, collieries and quarries Intrinsically safe circuits, type Ex. f Testing and certifying authorities Additional requirements for ciritical installations Motors for thermal power station auxiliaries Selection of a special-purpose motor... 

The motor/generator is modeled as an energy source/sink limited by its specific design capabilities. As a generator, it will absorb all excess power available while holding speed constant (synchronous) as long as it is electrically connected to the utility grid. 

Electric motors above 5,000 hp are custom-designed for the specific application, taking into consideration compressor characteristics and the power system parameter limitations. 

Failure of power or controls to the valve (generally related to the seismic capacity of the cable trays, control room, and emergency power). These failure modes are analyzed as failures of separate systems linked to the equipment since they are not related to the specific piece of equipment (i.e., a motor-operated valve) and are common to all active equipment. 

Electric motors are the most common drivers for the m ority of pumps, compressors, agitators, and similar equipment in the process industries. Process engineers should obtain the assistance of a qualified electrical engineer before completing motor specifications ior the wide variety of equipment applications and respective power sources. The use of standard specifications for the various types and classes of motors is helpful and reduces repetitious details. Be certain that the type of motor is properly matched to the service, atmosphere, load characteristics, and available type and power factor of the electrical energy to drive the motor. Some basic guides are summarized, but they cannot be used as all-inclusive rules to fit all plant or equipment condi-... 

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