Why Use a Clamp Meter to Measure Current When Installing Motors?
Step 1: Measure the phase separately. The phase voltage on the secondary side of the voltage transformer can be directly measured (using the same method as above), and the phase voltage can be directly measured (using the input terminal of the clamp meter). However, the probe needs to be inserted and the appropriate range needs to be selected. Its "notch" can only measure AC current with a dedicated clamp meter. Keep the pointer on the right and use it the same as a regular multimeter, gradually shifting from high to low in the case of unknown voltage;
Step 2: Measure voltage through parallel connection of probes. The clamp meter measures voltage through its accompanying multimeter. The clamp meter cannot directly "clamp" the voltage, so adjust the conversion switch to an appropriate range.
Usage of digital clamp table
1. Mechanical zeroing is required before measurement
2. Choose the appropriate range, first choose the large range, then choose the small range or estimate based on the nameplate value
3. When measuring with the minimum range and the reading is not yet clear, the tested wire can be wound a few times. The number of turns should be based on the number of turns in the center of the clamp, and the reading=indicated value x range/full deviation x turns
4. After the measurement is completed, the conversion switch should be placed at the maximum range
5. When measuring, the measured wire should be placed in the center of the clamp and the clamp should be tightly closed to reduce errors
Precautions for digital clamp gauge
1. The voltage of the tested circuit should be lower than the rated voltage of the clamp meter
2. When measuring the current of high-voltage lines, it is necessary to wear insulated gloves, insulated shoes, and stand on insulated pads
3. The jaws should be tightly closed and cannot be charged to change the measuring range
Using a clamp ammeter to measure the current of a single winding of an electric motor is a phase current, but it can cause difficulties in actual measurement, either by connecting all three pairs of winding wires to the outside; The current on the power line is always the line current; It is difficult and impractical to calculate the power of a certain motor. The power factor is an uncertain factor unless a power factor meter is also connected. However, it should be noted that due to the load, the power factor is constantly changing.
