Basic Electrical Installation Work

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10. Materials from which permanent magnets are made should display wide hysteresis loop, shown loop (b) Fig. The emf induced coil such that shown the right-hand side Fig. Magnetic hysteresis There are many different types magnetic material and they all respond differently being magnetized. Definition A mutual inductance henry exists between two coils when uniformly varying current ampere per sec- ond one coil produces emf 1 volt the other coil. Magnetic hysteresis loops describe the way which different materials respond being magnetized.12 Magnetic hysteresis loops: (a) electromagnetic material and (b) permanent magnetic material. 10. . A mutual inductance henry exists between two coils when uniformly varying current ampere per second one coil produces emf volt in the other coil. 10. The arc produced the stored magnetic energy being discharged across the switch contacts. The result will look like the graphs shown Fig. Some materials magnetize easily, and some are difficult magnetize. 10.Baisc Electrical Installation Work 206 FIGURE 10. Some materials retain their magnetism, while others lose it. When iron core subjected alternating magnetization, trans- former, the energy loss occurs every cycle and constitutes continu- ous power loss, and, therefore, for applications such transformers, a material with narrow hysteresis loop required. B H (a) B H (b) Magnetic saturation Definition Magnetic hysteresis loops describe the way which different materials respond being magnetized. Suitable materials will, there- fore, display narrow hysteresis loop, shown loop (a) Fig. Energy stored magnetic field When open the switch inductive circuit such electric motor or fluorescent light circuit the magnetic flux collapses and produces an arc across the switch contacts. The core electromagnet required magnetize easily, and lose its magnetism equally easily when switched off.12.12 and are called hysteresis loops.12.11 dependent upon the rate change magnetic flux and the num- ber turns the coil