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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0.008 inch). fiber locknut (self-locking nut). A type of self-locking nut used on a bolt that is subject to vibration — it cannot, however, be used on a bolt that is subject to rotation. A collar of resilient, or springy, fiber is locked into the end of the threads in the nut. The hole in the fiber is slightly smaller than the major diameter of the threads on the bolt on which it fits. When the nut is screwed onto the bolt, the threads press, but do not cut, into the fiber and cause so much friction that the nut cannot vibrate loose from the bolt. A fiber locknut can be reused as long as a wrench is needed to turn it onto the bolt. fiber optics. The branch of technology that deals with the transmission of light through long, slender, flexible fibers of glass or transparent plastic material. Transparent fibers arranged in a compact bundle have the ability to transmit an image from one end to the other, even if the bundle is bent around a corner. Fiber optic borescopes are used to inspect the inside of a structure without requiring any major disassembly. These instruments may be fitted with a light source to illuminate the inside of the device being inspected, and a camera to make a permanent record of what is seen through the eyepiece. fidelity. The accuracy with which an amplifier reproduces the signal applied to its input. field (electrical). A space across which electrical lines of force exist. field (magnetic). A space across which magnetic lines of force exist. field cleaning (turbine engine maintenance procedure). Cleaning the compressor blades, casings, and inlet guide vanes of a turbojet engine by spraying them with an emulsion-type cleaner, followed by a rinse with distilled or demineralized water. Field cleaning is done while the engine is motored by the starter or operated at a low RPM. field coil (electrical machine). A coil of insulated wire wound around a laminated steel pole shoe in an electrical motor or generator. Each motor or generator has two or more field coils that may be connected either in parallel or in series with the armature. Direct current flowing through the field coils of a generator produces magnetic flux which induces a voltage in the conductors of the armature as they pass in front of the pole shoes. The amount of voltage induced in the armature is determined by the strength of the magnetic field. A voltage regulator is normally used to control the amount of current flowing in the field coils, and thus the strength of the magnetic field. In a motor, torque is produced by the reaction between the magnetic flux produced by current flowing in the field coils and the flux produced by current flowing through the armature coils. field effect transistor. See FET. |
