The role of the current transformer is used to measure the larger current

The role of the current transformer is used to measure larger current, current transformer is a kind of current commutation device, symbols for CT. Its role is to put the large current into a small current, supply measuring instrument and relay the current chart, indirect measurement by large current. But also can isolate high voltage, to ensure the safety of staff and secondary equipment. Current transformer secondary side current is 5 Why can't a current transformer secondary side circuit? Current transformer secondary side is not allowed to open operation. In the current transformer secondary coil on the instrument coil impedance is small, the equivalent of running in the secondary coil short-circuit condition. Transformer secondary coil terminal voltage on only a few volts. Of the magnetic flux in core is very small. Although primary coil magnetomotive force can reach hundreds or thousands of Ann ampere-turns or larger. But most were established by short circuit secondary coil demagnetization magnetomotive force offset, only a small fraction of excitation magnetomotive force as the core to establish a magnetic flux in the core. 


If in running the secondary coil disconnection, vice side current is equal to zero, then the demagnetization effect of magnetomotive force disappears, and the original edge of magnetomotive force is constant, the original edge measured current all become excitation current, this will make the iron core of sharp, magnetic ac motor flux core severe fever that burn out the coil insulation, or make the high side of short circuit. Other electric fan motor secondary coil wholesalemotor.blogspot.com open out the high voltage is induced, it is very dangerous for instrument and operators so current transformer secondary side is not allowed to disconnect. Why can't a voltage transformer secondary side short circuit? If the short circuit in the operation of the secondary side lamination of voltage transformer, secondary coil impedance decrease greatly, can appear a lot of short circuit current, make the secondary coil burned due to severe fever. So in the operation of the transformer are not allowed to short circuit. General voltage transformer secondary side with a fuse. Only transformer of 35 kv and below, on the high side have a fuse when transformer short-circuit the purpose is to put it cut off from the high voltage circuit.