时间：2011-03-11 23:13来源：蓝天飞行翻译 作者：admin 点击：次
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The ignition systems used on almost all aircraft reciprocating engines are electrically shielded by enclosing the entire system in a conductive covering that is electrically grounded to the engine. electrical short (electrical system fault). An unwanted connection that provides a low-resistance path across an electrical circuit. Electrons flow through the short to ground without passing through the load. electrical steel. An alloy of low-carbon steel that contains up to about 5% silicon. Electrical steel in the form of thin laminations is used for the cores of transformers and armatures of electrical motors and generators. electrical strain gage. A device used to measure the amount of physical strain (deformation caused by a stress) in a piece of material. A strain gage is made of very fine wire mounted between two pieces of tissue paper, about the size of a postage stamp. The strain gage is bonded (glued) to the material in which the strain is to be measured, and the two ends of the wire are connected into a sensitive resistance-measuring bridge circuit. When the material on which the strain gage is mounted is under a tensile stress, the wire in the strain gage stretches — it becomes longer and thinner, and its resistance increases. When the material is under a compressive stress, the wire becomes shorter and larger in diameter, and its resistance decreases. The change in resistance is proportional to the amount of strain in the material, and the amount of strain is proportional to the amount of stress causing it. electrical strength. The maximum amount of electrical pressure (voltage) that can be placed across an insulator before it breaks down and allows electrons to flow through it. electrical symbols. Standardized graphic symbols that have been agreed upon as representing various components in electrical schematic diagrams. electrical zero (synchro system). A specific position of the rotor inside the stator of a synchro (a remotely controlled position indicating system). Electrical zero is used as a reference position for meshing gears and installing indicator pointers. electric drill motor. A series-wound, alternating-current motor used to drive a chuck which holds a twist drill. The motor is geared down so that it furnishes a high torque to the chuck. electric inertia starter (reciprocating engine starter). A type of starter for large aircraft reciprocating engines. A series-wound electric motor spins a heavy flywheel to store energy. When the flywheel is spinning at a high speed, the motor is disconnected, and the flywheel is connected to the engine crankshaft through a series of reduction gears and a slip clutch. electricity. A force caused by electrons moving from one atom to another. A deficiency of electrons is called a positive charge, and an excess of electrons is called a negative charge. The difference in electrical charges causes electrical pressure. When electrical pressure forces electrons to move in a conductor, heat is produced, and a magnetic field surrounds the conductor. |
