The principle of current transformer is based on the principle of electromagnetic induction. The current transformer consists of a closed core and a winding. Its primary winding turns are few, and it is in the line of the current that needs to be measured. Therefore, it often has all the current flowing through the line, and the number of turns in the secondary winding is relatively large. It is connected in series between the measuring instrument and the protection circuit. When the device is in operation, its secondary circuit is always closed, so the impedance of the series coil of the measuring instrument and the protection circuit is small, and the working state of the current transformer is close to the short circuit.
Current transformers have large currents in power generation, substation, transmission, distribution, and power lines, ranging from a few amps to tens of thousands of amps. In order to facilitate measurement, protection and control, it is necessary to convert to a relatively uniform current. In addition, the voltage on the line is generally high. Direct measurement is very dangerous. The current transformer acts as a current transformer and electrical isolation.
For pointer-type ammeters, the secondary current of the current transformer is mostly amperometric. For digital instruments, the sampled signal is typically milliampere. The secondary current of the miniature current transformer is milliampere, which acts as a bridge between the large transformer and the sampling.
ABSOLUTE MAXIMUM RATINGS
Operating free air temperature range
-40ºC to 85ºC
|Storage temperature range|
-40ºC to 100ºC
Peak wave solder temperature
300ºC for 10Seconds