58同城找货车拉货:高手帮我翻译一下啊

a transformer is a device that change ac electric energy at one voltage level into ac electric energy at another voltage level through the action of a magnetic field.it consists of two or more coils of wire wrapped around a common ferromagnetic core.these coils are(usually) not directly connected.the only connection between the coils is the common magnetic flux present within the core
state variables maybe defined as the minimum set of variables such that a knowledge of the values of these variables at time t0,together with any inputs u to the system for t>=t0,will allow the behavior of the system to be determined for t>=t0
air at atmosphere pressure is the most common gaseous insulation.the breakdown of air is of considerable practical importance to the design engineers of power transmission lines and power apparatus. breakdown occurs in gases due to the process of collision ionization.electrons get multiplied in an exponential manner, and if the applies voltage is sufficiently large, breakdown occurs.in some gases,free electrons are removed by attachment to neutral gas molecules;the breakdown strength of such gases is substantially large. an example of such a gas with large dielectric strenth is sulphur hexafluoride(SF6)