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C&G Unit 302: Principles of electrical science
Published in Trevor Linsley, Advanced Electrical Installation Work, 2019
A relay is an electromagnetic switch operated by a solenoid. The solenoid in a relay operates a number of switch contacts as it moves under the electromagnetic forces. Relays can be used to switch circuits on or off at a distance remotely. The energizing circuit, the solenoid, is completely separate from the switch contacts and, therefore, the relay can switch high-voltage, high-power circuits from a low-voltage switching circuit. This gives the relay many applications in motor control circuits, electronics and instrumentation systems. Figure 3.34 shows a simple relay.
Electrical science and principles
Published in Trevor Linsley, Electrical Installation Work Level 2, 2019
A relay is an electromagnetic switch operated by a solenoid. We looked at the action of a solenoid in Figure 2.54. The solenoid in a relay operates a number of switch contacts as it moves under the electromagnetic forces. Relays can be used to switch circuits on or off at a distance remotely. The energizing circuit, the solenoid, is completely separate to the switch contacts and, therefore, the relay can switch high-voltage, high-power circuits from a low-voltage switching circuit. This gives the relay many applications in motor control circuits, electronics and instrumentation systems. Figure 2.57 shows a simple relay.
Prototyping of automated systems
Published in Fuewen Frank Liou, Rapid Prototyping and Engineering Applications, 2019
A solenoid is an electromechanical device used to convert electrical energy into linear mechanical work to push or pull a ferrous plunger against a nonferrous load. A typical solenoid is shown in Figure 8.1. It can generate quick, linear motion. The small force (several ounces) is generated by magnetic force. Solenoids are found in many conventional machines, such as coin-operated machines, vending machines, coin-operated arcade games, or change machines; they all work on the same principle. They are also found in many electromechanical devices, such as copiers. One can also use a solenoid to switch an electrical circuit on and off; this is called a (mechanical) relay. When used as relays, small solenoid allows a low-power circuit to move a switch controlling the current in a higher-power circuit. The resulting linear work produced could either pull or push in configuration.
Applying an equivalent free settling ratio to enhance ferro-magnetic and para-magnetic particles’ separation efficiency using the influence of a magnetic field aligned with gravity
Published in Mineral Processing and Extractive Metallurgy, 2022
Hamed Dehghani, Mohammad Mehdi Salarirad, Hosein Asli
Following the theoretical considerations, a laboratory scale Magneto-Gravity Settling Device (MGSD) was designed and fabricated aimed at measurement of the TSV values of the particles. The device was made up of two main components: a magnetic coil and a settling tube located inside the coil. To get a precise record of the particles’ sinking behaviour, a magnetic field with constant intensity and gradient was required throughout the whole settling length of the settling tube. Due to the significant changes in the generated field intensity and gradient of permanent magnets and the poor penetration range of the field generated by such magnets, a solenoid was used. A solenoid can produce a magnetic field with a constant intensity and gradient and enabled adjustment of the field intensity (magnetic flux) by controlling the input electric current. The configuration of the MGSD device is depicted in Figure 3. Finite element analysis was used to model the flux generated by the coil for which the results are illustrated in Figure 4. As can be seen the coil is capable of producing a flux with a constant gradient. Table 2 summarises the main specifications of the magnetic coil.