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Motor controllers
Published in Raymond F. Gardner, Introduction to Plant Automation and Controls, 2020
A motor controller is a group of electromechanical devices used to manage the proper operation of motors, often under the direction of automated controls. Motor controllers start and stop motors and provide other functions that make systems work properly. Control can be initiated by pressure, temperature, flow, level, limit-sensing, or other types of switches. Motors can be wired using several techniques to operate at a single speed, several discreet speeds, or at variable speeds, and they may be wired to be unidirectional or reversing. Controllers may start small motors across-the-line or they may use one of several reduced-voltage options to bring large motors up to speed without excessive electrical stresses and large voltage dips. Motor controllers are an integral part of the plant operation.
Principles of Energy Conversion
Published in Hamid A. Toliyat, Gerald B. Kliman, Handbook of Electric Motors, 2018
Hamid A. Toliyat, Gerald B. Kliman
The small-angle reluctance stepper motors described above provide steps down to the 3-degree range. Much smaller steps can be realized by various schemes of coil excitation. Thus far, a full pulse of excitation current has been assumed in one coil of systems excited as in Fig. 2.93 or in one phase of systems excited as in Fig. 2.98. There are two principal functions of the stepper motor controller: (1) to supply current to the motor coils that is sufficient to overcome the inertial, friction, and load torques of the system; and (2) to supply current pulses at the proper rate to achieve the shaft velocity or the time to reach a specified position that is required. There are also several ancillary functions, such as overvoltage and overcurrent protection and short-circuit protection. In more exacting applications, the controller is often required to optimize system efficiency, reduce audible noise and mechanical vibrations and aid in many other system considerations. The principal nameplate parameters of a stepper motor controller are rated voltage, maximum output current, maximum output power or power per phase, and maximum pulse rate. In applying a controller to a given motor application, it is also necessary to determine the motor torque that will be developed at maximum controller current. This requires knowledge of the motor coil characteristics and the torque constant of the motor. Most manufacturers supply speed-torque motor characteristics, examples of which are discussed below.
Branch Circuits and Feeders
Published in Moncef Krarti, Energy-Efficient Electrical Systems for Buildings, 2017
Unlike other building electrical loads such as lighting and receptacles, motors have controllers in order to achieve several functions: start manually or automatically, change the direction and the speed of rotation, and provide protection from either overload or short-circuit currents. There are several motor controllers: The simplest motor controller types include manual starters used for small motors (less than 1 horsepower) with 1, 2, or 3 poles.Magnetic starters are also simple motor controllers and include three main types: open type, combination type, and group mounted.Full-voltage nonreversing (FVNR) magnetic starters are used for full-voltage starting and stopping of AC squirrel cage motors.Full-voltage reversing (FVR) magnetic starters are used for full-voltage starting, stopping, and reversing of AC squirrel cage motors. They are available in either horizontal or vertical arrangements.
Automatic optimization of centrifugal pump based on adaptive single-objective algorithm and computational fluid dynamics
Published in Engineering Applications of Computational Fluid Mechanics, 2022
Hui Li, Yong Han, Weidong Shi, Taavi Tiganik, Ling Zhou
The pump is one of the most popular and important fluid-conveying equipment (El-Emam et al., 2022; Kim et al., 2015; Tong et al., 2020). As reported by the European Commission, the pump system account for 22% of the world’s motor energy consumption (Shankar et al., 2016), and centrifugal pump contributes to about 80% of all pumps due to their high efficiency and wide range of specific speed number (Ji et al., 2021). Therefore, many methods are proposed to improve the efficiency of the pump system (Armintor & Connors, 1987; Kaya et al., 2008; Suh et al., 2015). The remarkable method is to use variable frequency drives, which have numerous potential for energy saving. However, the pump system efficiency is determined by the pump, motor, controller, and so on. Improving pump efficiency can be done simultaneously with other methods to improve pump system efficiency without increasing manufacturing costs (Mandhare et al., 2019). In addition, for manufacturers, pump efficiency is an important criterion, as well as product competitiveness.
Numerical simulation of ball bearing flow field using the moving particle semi-implicit method
Published in Engineering Applications of Computational Fluid Mechanics, 2022
Wei Wu, Chunhui Wei, Shihua Yuan
To obtain the oil distribution of bearing lubrication at different speeds, single lens reflex (SLR) camera and other equipment are used to capture clear pictures to analyze the distribution of lubricating oil. The test rig is mainly comprised of the motorized spindle, SLR camera, temperature sensor, motor controller, parallel light, test bearing and a peristaltic pump, as shown in Figure 4. The motor controller can control the speed of the motor, thus controlling the speed inner ring. The peristaltic pump is composed of gear pump and brushless DC motor, which can regulate the flow rate of the oil supply. The specific parameters of the test apparatus and sensor are shown in Table 4. When taking pictures with SLR camera, in order to obtain a clear picture of the distribution of lubricating oil in the bearing cavity, it is necessary to select an appropriate shutter speed according to the rotating speed of the bearing. The selection basis of shutter speed is shown in Table 5. During the test, first irradiate the parallel light on the bearing end face, then select the appropriate shutter speed, set the appropriate aperture, and finally take photos.
Energy harvesting efficiency analysis of counter-rotating horizontal-axis tidal turbines
Published in Ships and Offshore Structures, 2022
Yu Cao, Jiazhi Wang, Boyin Ding, Shiming Wang, Yong Bai
Based on the designed parameters and the working characteristics of the CRHATT, the experimental procedure shown in Figure 6 is proposed and carried out. As shown in Figure 6(a), the circulating water platform is composed of a motor, pump, flow meter, power quality analyser, motor controller and control centre. The motor provides flow velocity to circulate water by driving the pump. The control centre can adjust the motor by controlling the motor controller to adjust the water flow velocity. The flow meter can measure and transmit the velocity value of the oncoming flow to the control centre in real time. The power quality analyser can measure the output power parameters of the generator in real time and transmit them to the control centre. The circulating water platform is shown in Figure 6(b). Figure 6(c, d) shows the physical model of the dual rotors. Figure 6(e) shows the physical model of the 100 W low-speed tidal generator.