方法 から 測定 ct 極性 あり マルチメータ
方法 から 測定 ct 極性 あり マルチメータ
電流 変圧器, CT: 電磁 電流 変圧器 is 広く 使用済み in 電源 システム, および its 動作 原理 is 類似 to that of 変圧器。
特性 of 電流 変圧器 are as follow: (1) The 1次 コイル is connected in 直列 in the 回路 with few turns, so the current in the primary coil depends totally on the load current of the circuit to be tested, but has nothing to do with the second current; (2) The インピーダンス of the current coil of the 機器 and リレー connected to the セカンダリ コイル of the 電流 トランス IS 非常に 小さい, SO アンダー 通常 状況, The 電流 トランスフォーマー 実行 IN A ニア 短絡 状態。
The ratio of primary and secondary rated current of current transformer is called the rated mutual inductance ratio of current transformer: kn=I1n/I2n.
なぜなら the 定格 電流 I1n of the プライマリ コイル has been 標準化 and the 定格 電流 I2n of the セカンダリ コイル is unified to 5(1 or 0.5) A, the 定格 相互 インダクタンス 比 of the 電流 トランス has also been standardized. Kn can also be approximately 表現 as the turns ratio of the プライマリ and セカンダリ 巻線 of the トランス, that is, where kn≈kN=N1/N2 is the number of turns of the 1次 and 2次 巻線。
関数 of 電流 変圧器 is to 測定 相対的 大 電流。
一般的に 話す, if you 欲しい to measure the current of 400A, what should you do without a 400A ワット時 メートル? したがって, you should use a current transformer to change a 大きい current into a 小さい 電流 and input it into the watt-hour meter. The 変圧器 has a variable ratio, for example, 200/5 is 40 times that of the watt-hour meter, which means that your watt-hour meter has been charged once. in fact, you have used 40 degrees of electric, and there are many levels of transformers, with 15/5。
For the field, the best way to determine the polarity of the transformer is to use a dry battery and a piece of pointer multimeter MF47. With wires, it is the most direct and easy to see, and the accuracy can reach more than 90 percent . The method is very simple. The standard secondary transformer with P1 P2 on the primary side is S1S2 K1K2, etc. Connect the positive electrode on the secondary side of P1 to the negative electrode of S1, and the secondary side is directly connected. Then directly short-circuit the DC current to the primary side of the transformer with the battery. At this time, you will see that if the pointer swing of the multimeter is extremely positive clockwise, it is negative counterclockwise, indicating that the internal winding is wrong. At this time, you should observe it in detail. Because the pointer swing is not large, it is advisable to use two 1# batteries in the same way, because it is too dangerous to have too many batteries, and stop for half an hour or replace the batteries after about 10 tests. Because the battery was very hot during the test, it is suggested that you should not be lazy to use the 126V converted from alternating current because you saved the battery, but the error increased and the safety decreased.
