Using the Clamp Ammeter to Asses the Balance of the Three-Phase Circuit
Clamp the A, B, C three-phase wires connected to the load (such as a motor) into the jaws at the same time. If there is no indication, it means that the three-phase circuit is balanced. If there is a reading, it means that there is a zero-sequence current, indicating an imbalance. Clamp two of the three-phase wires, and the displayed reading is the current value of the unclamped phase.
If the loop current to be tested is less than the number of turns in the clamp mouth (set as N turns), then divide the current value indicated by the meter head by the number of turns N, which is the resistance value to be measured.
If the current to be measured is greater than the maximum range current, a current transformer can be used. The method is: cut the number of times of the current transformer in the load circuit into a short circuit, clamp the jaws of the clamp ammeter into the secondary short-circuit wire, and multiply the measured current by the transformation ratio of the current transformer, which is the measured load circuit current value.
The main "specialties" of the clamp ammeter
Clamp ammeter We know its main "specialty" from its common name, and we sometimes call it a current measuring clamp. It is an electrical instrument for measuring large currents. It can measure up to 1000 amperes of alternating current, and the minimum can only measure the current of 1 ampere. If it is lower, it will not be accurate. Therefore, its accuracy is only 2.5 to 5 grades, and there are many things to pay attention to when measuring large currents, which need to be memorized by beginners.
Multimeter with Clamp Meter
With the promotion of digitalization and the research and development of new products, more and more instruments have adopted digitalization and become a development trend, and analog instruments have gradually withdrawn from the "stage" of use. Now the clamp ammeter has also appeared digital, and its function is no longer a single measuring instrument. While the measurement accuracy of the digital clamp ammeter is improving, the physical quantities it measures are also "enriched", such as current, voltage, resistance, active power, frequency, phase angle, power factor and other physical quantities. Has the dual function of multimeter and clamp ammeter. I think such an instrument will be favored by the majority of electrical technicians in the future.
