Electric-motor drive

Piping and pumps used for transfer of the butanols can be made of the same metal as tanks. Centrifugal pumps with explosion-proof electric motor drives are recommended (34). 

Nearly all the energy used in the concentrators is for electric motors driving ball mills, cmshers, pumps, and the agitators of flotation cells. About half the energy is used for grinding the ore to the proper size. 

Applications include electric motor drives for conveyors and other material handling equipment such as stacker reclaimers, crushers, haulages, ball mills, cranes, hammer mills, rotary dryers, centrifuges, reciprocating pumps, winches, fans and wire drawing machines. 

Combustion air blower located at the base of the flare stack, complete with the electric motor drive and proper control system. 

Fan motor systems The methods by which an electric motor drives a fan or pump system. 

Note that this is horsepower available to the cylinders. It includes a 95% mechanical efficiency incorporated into the bhp/MMCFD curves. The rating of a gas engine must be such that its delivered horsepower is at least 420 hp, or if an electric motor drive is used, the mechanical losses of the intermediate frame (about 5%) must be added to arrive at the required motor shaft horsepower. 

The volume and pressure control methods with electric motor drive for centrifugal fans are/ ... 

Water-treatment plant may include one or more electric motors driving feedwater pumps or dosing pumps. Dosing pumps are usually very small and will not cause noise problems. Water pumps may be considered as for the feedwater pumps already described. 

Among the advantages of electric motor drive are compactness and ease of control. The internal combustion engine is preferred for mobile units, emergency standby units, or where electric power is not available. 

Fig. 4.4.3 Experimental set-up for the MRI investigation of Taylor-Couette-Poiseuille flow. The electrical motor driving the shaft, as well as the pump, are placed 7.3 m away from the scanner to avoid interference with the magnetic fringe field.

Rotor speed control is an integral part of the process of rate of temperature rise. The modem mixer is generally supplied with variable speed, constant torque electric motors driving via gear reducers or by a hydraulic drive system which has a motor shaft mounted tachometer to control rotor speed. Systems that can monitor, adjust and record the mixer rotor speed provide improvement in resultant compound uniformity. Changes in rotor speed within a cycle can be programmed. 

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. 

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 low power requirement is ideally suited to an electric motor drive, with the standard 440V (50 cycles per second), 3 phase connection. AJAX confirmed this choice, advocating a 2-pole motor of the above characteristics to meet the rotational speed of 2900 rpm. This is advantageous because motors of 4 poles or more greatly increase the unit cost. 

This pump uses a closed impeller, mechanical seals, and is constructed of stainless steel 304L. The small power load of approximately 3.5 kW is supplied by an electric motor drive employing a horizontal shaft. The design casing pressure is sufficient to give a 30% safety factor above the total head required. Mechanical seals are preferred to a packed box arrangement due to their superior ability to contain the corrosive and toxic acid liquor. 

Fig. 6.5 Schematic view of an SSE. Its main components are a rotating screw within a stationary barrel. Polymer is fed through an inlet port and leaves the machine through a closure equipped with a die at the discharge end. Not shown in the figure are the electric motor drive and gear reducer for adjusting the rotational speed.

The second failure involves an error made during the weld repair of an electric motor drive shaft, which again resulted in a fatigue failure. 

The main components of any centrifuge are an electric motor and drive shaft (together referred to as a spindle) and a rotor to hold samples in containers, typically centrifuge tubes. An electric motor drives the centrifuge and applies acceleration to the rotor, attaining an appropriate number of revolutions per minute (rpm) and associated centrifugal (g) force (see Figure 6.4). 

This problem was taken from Reference 5.56. Assume that the electric motor efficiency is 94%. Calculate the power required for an electric motor drive for a compressor to compress a process gas containing propane, butane and methane from 5 °C (41°F) and from 1.4 to 7.0 bar (20.3 to 101 psia). The composition of the gas in mole percent is CsHg = 89.0, n-C4Hio = 6.0, and C2H6 = 5.0. The flow rate is 1090 kgmoEh (2403 Ibmol/h). 

The total power required by the electric-motor drive is. 

Assuming that a squirrel-cage electric-motor drive for the pump is selected, the electric-motor efficiency is determined by interpolating between 100 and 1,000 hp (in Table 5.9). An acccurate determination of the motor efficiency re-... 

Compressor drives. Compressors and blowers in fluid cracking units may be either steam or electrically driven (209). Steam turbines were preferred over electric-motor drives in the design of early units, partly because of fear of a power failure. However, under some circumstances, the economics favor the use of electric motors. Several units have been built with electrically driven main air blowers, and at least one refiner has selected electric motors for the air blower, gas compressor,... 

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