英文文献
相机回收初夜难枕Cirtcuit Breakers
A circuit breaker is mechanical switching device capable of making，and breaking currents under normal circuit conditions and also making。carring for a specified time ，and mediujm in which circuit interruption is performed may be designated by a suitable prefix， for example,air—blastcircuit breaker,oil circuit breaker。The circuit breakers currently in u can be dlassified into the following categories according to the arc-quenching principles:air swetches oel ciryit breakers，minmum—oil circuit breakers，air—blast circuit breakers，the magenetic air circuit breakers,minimum—oil circuit breakers，aer—blast circuit breakers,the by voltage,insulation levelcurrent，interrupting capabilities,transient recovery coltage，interrupting tiome,and trip delay。The nameplate on a circuit breaker usually indicates：商场英文１.The maximum steady—state current it can carry, 2. The maximum interrupting current,3。 The maximum line voltage,4.The interrupting time in cycles, The interrupting time in may last form 3 to 8 cycles on a 60 Hz system. To interrubt large current
s quickly， we have to ensure rapid cooling. High-speed interruption lunits the damage transmission lines and equipment and， equally important，it helps to mainmain the stability of the system whenever a contingency occurs。 The main parts of a circuit breaker are usually:arc—quenching chamber （or interrupter with moving and fixed contacts) operating mechanism and supporting structures。
Air Switches-With increasing currents and voltages， spring-action driving mechanisms were developed to reduce contact buring by faster-opening operation。Later,main contacts were fitted with arcing contacts of special material and shape,which opend after and clod before the main contacts。Further improvements of the air switch were the bursh—type contact with a wiping and cleaning function，the insulating barrier leading to arc chutes，and blowout coils with excellent arc—extinguishing properties.The features，as well as the horn gap contact，are still in u in low voltage as and de breakers。
Oil Circuit Breaker Around 1900, in order to cope with the new requirement for “interrupti
ng capacity”,AC switches were immerd in a tank of oil. Is very effective in quenching the arc and establishing the open break after current zero.Deion grids,oil—blast features,pressure-tight joints and vents，new operating mechanisims，and multiple interrupter were introucedover veral decades to make the oil circuit breaker a reliable apparatus for system voltage up to 362Kv。
山楂怎么做好吃
Lingting protection
The thunder and lightning protects to connect the ground; Connect the ground to avoid the thunder the most important link of the technique, ignore is a shot thunder， respond the thunder of the thunder or other form， and avoid the thunder work most all of nd into the earth the thunder electric current。 Store the thunder energy to behave the type to build the , current technology to still reach to not arrive， and therefore have no the reasonable but good connect the ground equip to is impossible to speak about to defend the thunder.Therefore say the design, the construction is very high standard to connect the ground system is a heavy inside that defend thunder's work it heavy. High electric pot
中华人民共和国行政诉讼法
ential that For long time， people have an illusion， and think that connect the ground electric resistance more small avoid the thunder result and then more like， quilt object that protect safety。 Certainly the electric resistance is more the small is more quick, strike by lightning to rerve time more short, the risk is more small, electric voltage of its stride, get in touch with the the electric voltage produce the machine too the more the ?But， construction that the fulfillment proof of near and more than ten in the last years, with its say that connect the worth importance of ground electric resistance, not equal to say that connect the ground to equip more reasonable， importanceElectricity equipments, demand variety that now’s city, there is lots of in a building inside not the congeniality connect the ground device, if avoid the thunder to connect the ground, electricity the safety to connect the ground， AC power the work to connect the ground， correspondence and calculator system to connect the ground, according to the fulfillment proof， totally u to connect the ground is an application most for extensive connect the local type。 ＆＃61550；
That A, the independence connect the ground： As above part for demand for speak ofin
g connecting the ground of， all distinguish to independently establish the own to connect the ground system， and this kind of connect the local type to call the independence to connect the ground. Its advantage is each system and can’t result in the mutual interference, and this is particularly important to correspondences systems。But the adoption independence that network easily were strike by lightninged is bad, so besides have to defend to explode the dangerous environment requesting to must want the adoption the independence of avoid the thunder method generally not lay claim to the way to connect the ground。
Two， totally u to connect the ground： Also call unify to connect the ground。The each system that it connect the ground the demand unifies to receive a connect the ground to equip top， or is originally each system of connect the ground device to pass the underground to perhaps and up link， make them the electricity for becoming of its to connect the ground to unify the ground net with metals conductor， like this of connect the local type is to totally u to connect the ground。 it is current to u to connect the ground totally applied the most extensive connect the local type. ＆#61550;
Each system that Three， connect the ground 1:00： Method that connecting the ground line to receive to connect the same point or same metals flat surface of line of ground mother of each system is up, like this call” connect the ground 1：00" method。 connect 1：00 the ground method can resolve the etc。 Electric potential to connect the ground line the problem， can therefore lower of each system can cancellation of top of interference fundamental for of interference degree， particularly is 50 HZ work signal to system, and connect the ground method on the engineering to get the extensive application therefore and 1：00。 ＆#61550;
Four， the many point connect the ground:The ground line of connecting of each system adopt many points short on-line connect the local type, and call to much order to connect the ground. ；
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