Advantages of clamp on Ammeter- Clamp Ammeter to measure three-phase current
Advantages of clamp on Ammeter
The biggest advantage of clamp Ammeter is that it can measure current without electricity. Clamp Ammeter is mainly divided into pointer type and digital type. Clamp Ammeter can be divided into clamp Ammeter for AC measurement and clamp Ammeter for AC and DC electromagnetic system according to different results and purposes.
Generally, when measuring the current, the circuit to be measured needs to be disconnected before the Ammeter or the primary winding can be connected to the circuit to be measured. The clamp Ammeter can measure the measured current without disconnecting the measured circuit. Although the accuracy level of clamp Ammeter is not high, usually 2.5 or 5.0, it is widely used because of its convenience. Clamp on Ammeter is generally used to measure load current with voltage not exceeding 500v. The commonly used clamp Ammeter can be divided into transformer type and electromagnetic type according to its different structure. Among them, there are t301 clamp Ammeter measuring only AC current, t302 clamp Ammeter measuring both AC current and AC voltage, and mg series AC/DC clamp Ammeter.
Clamp Ammeter to measure three-phase current
Three phase current needs to be detected one phase at a time. After all, three-phase current is unbalanced.
Measurement method:
1. First, correctly select the voltage level of clamp type Ammeter, and check whether its appearance insulation is good, whether there is damage, whether the pointer swings flexibly, and whether the jaw is rusted. Estimate the rated current based on the motor power to select the range of the meter.
2. Read the instruction carefully before using the clamp Ammeter to find out whether it is an AC or AC/DC clamp meter.
3. Since the clamp Ammeter itself has low accuracy, the following method can be used to measure small current: first, wind the wire of the circuit to be measured for several turns, and then put it into the jaw of the clamp for measurement. At this point, the current value indicated by the clamp meter is not the actual value being measured, and the actual current should be the reading of the clamp meter divided by the number of coils wound on the wire.
4. When measuring, the jaws of the clamp type watch should be tightly closed. If there is any noise after closing, the jaws can be opened and reset once. If the noise cannot be eliminated, the joint surfaces on the magnetic circuit should be checked for smoothness. If there is dust, it should be wiped clean.
5. The clamp meter can only measure the current of one phase wire at a time, and the measured wire should be placed in the center of the clamp window. It is not allowed to clamp all multiphase wires into the window for measurement.
6. The voltage of the tested circuit should not exceed the value indicated on the clamp meter, otherwise it may cause grounding accidents or electric shock hazards.
7. Measure the working current of the cage asynchronous motor during operation. According to the current, it is possible to check and judge whether the motor works normally, so as to ensure the safe operation of the motor and extend its service life.
8. During measurement, it can be measured once for each phase or three phases. At this time, the number on the meter should be zero (because the sum of the three phase current is zero). When there are two phase lines in the jaw, the value displayed on the meter is the current value of the third phase. By measuring the current of each phase, it can be judged whether the motor is overloaded (the measured current exceeds the rated current
