Why are clamp meters so dependent on true RMS?
When choosing a clamp meter, the most frequently asked questions are "how accurate" and "accurate". There are many factors that affect the accuracy of the clamp meter, such as design/workmanship, bandwidth, frequency response, including whether a suitable range is selected, all of which will affect the reading. However, among all these factors, one of the most important factors is the true RMS measurement, especially for industrial users with a wide variety of electrical equipment and complex electrical environments.
The non-true effective value, that is, the average response instrument, is mainly for the measurement of the sine wave of the standard power frequency. A common implementation principle is to convert the measured arithmetic mean reading x1.1 into a sine wave 'effective value' reading. This is no problem at all in an environment where the electrification environment is relatively simple, such as buildings and properties.
In a wider industrial environment, especially the use of more and more equipment such as frequency conversion, rectifiers, and inverters, the actual waveforms are becoming more and more diverse, and even more and more high-frequency noises are introduced, so it is necessary to Accurate measurement, true effective value becomes one of the most important factors.
When it comes to noise or harmonics, another important concept has to be mentioned: low-pass filter (LPF). The implication is that only the low-frequency current and voltage can be measured, and the high-frequency part will be cut off and not calculated. It can be said that only the true RMS clamp meter with low-pass filtering is the truly valuable 'true RMS'.
