Can a clamp meter be used to measure the leakage current of air conditioning?
Can air conditioning leakage be measured with a clamp meter?
1、 Background
During the installation and maintenance of air conditioning, a clamp meter is often used to measure the current, which is convenient and fast to use. When using a clamp meter to measure current, simply set the gear to the appropriate range and clamp the circuit of the measured current. The following figure is an example of measuring the current of the live wire. So, can we use a clamp meter to measure the leakage current?
2、 How to use a clamp meter to measure leakage current?
When measuring, directly clamp the fire zero line with a clamp meter. If the reading is zero, it means that the line has no leakage. If the reading is not zero, it means that there is leakage in the circuit.
3、 What principle is used?
The basis for measuring current with a clamp meter is the principle of a transformer. When there is no leakage, the clamp meter simultaneously clamps the zero wire, and the two currents are of equal magnitude and opposite direction. Therefore, the magnetic field generated by them is also of equal magnitude and opposite direction, and the two magnetic fields completely cancel out. Therefore, there is no magnetic field in the iron core of the clamp meter, and no induction signal will be generated. When there is leakage in the circuit, the clamp meter still clamps the zero line, but at this time, the live line current is not equal to the zero line current, but greater than the zero line current. Therefore, the magnetic field generated by the live line current is stronger than that generated by the zero line current, and the two magnetic fields cannot be completely offset. When there is leakage, there will be a magnetic field in the iron core, which can generate an induction signal, which is then converted into a reading.
3、 Is it suitable for air conditioning leakage?
1. When air conditioners are used in users' homes, they are basically equipped with Residual-current device. The action leakage current of Residual-current device is 30 mA. When leakage occurs, they basically trip first.
2. In a power supply environment without leakage protection, if the leakage is relatively small, it is estimated to be difficult to measure. The measurement accuracy of the clamp Ammeter is between 1-2%. Taking the running current of 10 A as an example, the error is 200 mA.
