Measurement methods:
1. First, select the voltage level of the clamp-type ammeter correctly, and check whether the appearance of the ammeter 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. Before using the clamp ammeter, you should read the manual carefully to find out whether it is an AC or AC/DC clamp meter.
3. Due to the low precision of the clamp-type ammeter itself, when measuring small currents, the following method can be used: first, wind the wire of the circuit under test a few times, and then put it into the jaw of the clamp-type meter for measurement. At this time, the current value indicated by the clamp meter is not the actual value being measured. The actual current should be the reading of the clamp meter divided by the number of turns of the wire.
4. The jaws of the clamp meter should be closed tightly during measurement. If there is any noise after closing, the jaws can be opened and repeated once. If the noise cannot be eliminated, check whether the joint surfaces on the magnetic circuit are smooth and clean. Wipe clean.
5. The clamp meter can only measure the current of one-phase wire at a time. The measured wire should be placed in the center of the clamp window, and multi-phase wires cannot be clamped into the window for measurement.
6. The voltage of the circuit under test cannot exceed the value indicated on the clamp meter, otherwise it is easy to cause a grounding accident or risk of electric shock.
7. Measure the working current of the squirrel asynchronous motor in operation. According to the size of the current, it can be checked and judged whether the working condition of the motor is normal, so as to ensure the safe operation of the motor and prolong the service life.
8. When measuring, it can be measured once per phase or three phases. At this time, the number on the meter should be zero (because the three-phase current phasor sum is zero). When there are two phase wires in the jaws, the meter should be zero. The value displayed above 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 value), the internal motor or (the device that converts other forms of energy into electrical energy is called power supply) Whether there is a problem with the power supply voltage, that is, whether the three-phase current imbalance exceeds the limit of 10%.
9. Before measuring the clamp meter, you should first estimate the magnitude of the measured current, and then decide which range to use. If it is impossible to estimate, you can use the maximum range first and then change it to a smaller one for accurate reading. You cannot use the low current gear to measure large currents. to prevent damage to the instrument.
