時間：2011-03-11 23:18來源：藍(lán)天飛行翻譯 作者：航空 點擊：次
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thermal coefficient of resistance. The ratio of the change in resistance of a material to a change in its temperature. The coefficient is positive if the resistance of the material increases as its temperature goes up. The coefficient is negative if the resistance becomes less as the material gets hotter. The thermal coefficient of resistance is usually expressed in such units as ohms per degrees Celsius (Ω/°C). thermal conduction. A method of heat transfer in which heat energy is transferred from one body into another when the bodies are in direct contact. thermal conductor. A material that transfers heat energy by conduction with very little loss. Most metals are good thermal conductors, and such materials as paper, wood, and water are poor thermal conductors, or are thermal insulators. thermal cutout (electric motor component). A special circuit breaker mounted inside an electric motor. The thermal cutout opens the power lead to the motor if the motor overheats for any cause. These causes could be: too great a load, too low an operating speed, or lack of cooling airflow. As soon as the motor cools down, the thermal cutout automatically resets itself, and the motor runs again. Thermal cutouts are also called automatic-reset circuit breakers. thermal dimpling. See hot dimpling. thermal relief valve (hydraulic system component). A pressure relief valve in a hydraulic system that relieves the pressure which builds up when heat expands the fluid. Thermal relief valves are installed in sections of the system in which fluid can be trapped, usually in the lines between the selector valves and the actuators. When fluid in these lines absorbs heat and expands, the thermal relief valve momentarily unseats and releases enough fluid back into the system return manifold to relieve the high pressure and prevent damage to the system. |
