Electric motors voltage

The centrifugal pump directly driven by a variable-speed electric motor is the most commonly used hardware comoination for adjustable speed pumping. The motor is operated by an electronic-motor speed controller whose function is to generate the voltage or current waveform required by the motor to make the speed of the motor track the input command input signal from the process controller. 

Note A supply system having a voltage unbalance of more than 5% is not recommended for an industrial application, which may have a number of electric motors connected on it. Rural distribution, however, is an exception due to excessive LT loads on the same network (Section 7.6), but such loads are mostly individual and not of the industrial type,... 

For in-house correlations, the cost of electric motors should be correlated vs. horsepower with voltage, speed, and type of construction as correction factors or parameters. Correction factors for explosion proof or open drip-proof housings could he developed if most of the data is for TEFC (totally enclosed fan cooled) motors. Similarly, correction factors could be developed for 1,200 rpm and 3,600i pm with l.SOOrpm as the base. 

Tlie electric motor is basically a standard, single-speed, single-voltage motor. When receiving a variable frequency, the motor will operate at a variable speed. The motor may be either an induction or synchronous motor. The decision as to which type to apply is essentially similar to that for a single-speed application. 

Driver. If steam is available, a common choice is a steam turbine driver for the main pump and an electric motor for standby. Some plants prefer two electric motor-driven pumps. Give the minimum steam condition. Give the expected voltage drop on the electric system if more than 10% is expected, especially on large systems. 

Apart from considerations given to corrosion resistance and suitability for hazardous (classified) areas, the selection of electric motors for oil field applications is the same as the selection of electric motors for other industrial applications. One exception may be the selection of motors for areas where electric power is self-generated. Frequency and voltage variations may occasionally occur at such locations. For such locations, consideration should be given to specifying motors which are tolerant to at least 10% voltage variations and 5% frequency variations. 

The tip is first brought near to the sample via a coarse Z positioner, such as a controlled approach piezo-electric motor. This provides a 10 A step size and so is capable of very precise and controlled movement. As soon as a tunnelling current is detected, the tip is stopped and the fine control system is operated. Thus the lip is mounted on the end of a hollow, cylindrical piezo crystal, a tube scanner (a piezo-electric crystal can be made to deform under the influence of a voltage applied across it). The tube scanner has four strip electrodes on the outside, providing movement in the x and y directions (lateral movement), and one electrode covering the whole of the inside. A... 

Low voltage switch gears, electric-motor parts... 

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. 

Motive power batteries are generally of higher quality than SLI batteries. Their most important characteristics are constant output voltage, high volumetric capacity at relatively low unit cost, good resistance to vibration and a long service life. Since electric motors used for motive power require... 

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