How does the current transformer in ac motor work?
Ac current transformer in ac motor The effect is to make current phase difference Ac motor of current transformer is actually has a magnetic core inductance coil, inductance coil has the characteristics of the dc resistance communication, so that the current phase. The principle of ac motor is that the stator coil generates a rotating magnetic field, which makes the rotor spin fast. To produce a rotating magnetic field, the current transformer is required to make the current phase difference.
The differential protection of ac motor is in the three-phase power supply (cabinet) of the motor, which is equipped with three current transformer: A1, B1, C1. At the end of the three-phase winding of the motor, there are three current transformers: A2, B2 and C2, before being linked to "neutral". The six current transformers are the same, and the secondary winding receives the differential protection relay. When the motor is working, A1, A2 is equal to zero, the difference is zero, and the differential protection relay has no output. (B1, B2, C1, C2) The proposal: still seek a book to see, as the electrical design personnel, should have more in-depth understanding, the Internet is difficult to get.
The electromagnetic current transformer is widely used in the electric system, and its working principle is similar to the transformer. The wiring of the current transformer, as shown in the left. The characteristics of the current transformer is: (1) a coil in series in the circuit, and as a result, the number of turns in a coil current depends on the load current of the circuit under test. And has nothing to do with the secondary current; (2) current transformer secondary coil of the current meter and relay to the coil impedance is very small, so under normal circumstances, current transformer run in to a short-circuit condition. The ratio of a current transformer to a second rated current is called the rated mutual inductance of a current transformer Because the current I1n is standardized, the secondary coil rated current I2n is uniformly 5 (1 or 0.5), so the mutual inductance ratio of current transformer is also standardized. The kn can also be approximated as the number of turns for the transformer one and the second coils, which is the number of turns in the kn = N1 / N2 type, the number of turns for one or two coils. Current transformer is used to measure large current.
