Types and use of clamp ammeter
Types of clamp ammeter
1. AC clamp ammeter
The AC clamp ammeter consists of a current transformer and a rectifier ammeter. When you hold the wrench of the clamp meter tightly, the iron core of the current transformer is opened, and it is used to cover the measured current conductor, and then the wrench is loosened. This wire serves as the primary winding of the current transformer, and the secondary winding of the current transformer is on the iron core, which is connected with a magnetoelectric ammeter through a rectifier. According to a certain ratio relationship between the primary and secondary windings of the current transformer, the rectifier instrument can display the current value of the measured line. By changing the conversion ratio of current transformer by changing the changeover switch, different ranges from one ampere to tens of thousands of amperes can be obtained.
2, AC and DC dual-purpose clamp current
As shown in the above figure, the AC and DC clamp ammeter is similar in appearance to the AC clamp ammeter, and it is composed of electromagnetic measuring mechanism. When the measured current wire is clamped, a magnetic field is generated in the iron core, and the moving iron plate of the measuring mechanism located in the gap of the iron core is deflected by the magnetic field to drive the pointer. Its working principle is similar to that of the electromagnetic instrument, so it can be used to measure both AC current and DC current.
3. Multi-purpose clamp ammeter
Multi-purpose clip-on ammeter is composed of clip-on transformer and multimeter. When the connecting wire of the transformer is pulled out, the jaw does not work and can be used as multimeter.
Use of clamp ammeter
1. Choose a suitable range stop, and do not use a small range stop to measure large current. If the measured current is small, put the current-carrying wire into the jaw for measurement, and divide the reading by the number of windings before the actual current value. After the measurement, put the transfer switch in the maximum range position (or closed position) for safe use next time.
2, don't switch range block in the process of measurement, so as not to bend the hands; If it is necessary to shift gears, the tested wire should be withdrawn from the jaws before shifting gears.
3. Pay attention to that the voltage on the circuit is lower than the rating of the clip-on ammeter, and it is not allowed to measure the current of the high-voltage circuit with the clip-on ammeter with low voltage level, otherwise it will easily cause accidents or electric shock.
4. In thunderstorm days, it is forbidden to use clamp ammeter for outdoor measurement.
