FAQ | Feb 21,2023
In fact, there are many classifications of current sensors, and different classifications are different in use. We first need to choose the appropriate current sensor according to the use requirements, and then use according to the product instructions.
Conventional current sensors have four pins: positive (+), negative (-), measuring (M), and ground (0), but line current sensors do not have these four pins, but red, black, yellow, and green leads correspond to the positive electrode, negative electrode, measuring end, and ground. At the same time, most sensors have an internal hole through which a wire passes when measuring primary current. The size of the aperture has a certain relationship with the product type and the size of the measured current.
Regardless of the type of current sensor, the wiring of the pins during installation shall be carried out according to the conditions specified in the instruction manual.
1. When measuring AC power supply, it must be forced to use bipolar power supply. That is, the positive (+) terminal of the sensor is connected to the “+ VA” terminal of the power supply, and the negative terminal is connected to the “-VA” terminal of the power supply. This connection is called a bipolar power supply. At the same time, the measuring terminal (M) is connected to the “0V” terminal of the power supply via a resistor (single-finger zero magnetic formula).
2. When measuring DC current, you can use single-pole or single-phase power supply, that is, short connect the positive or negative terminal with the “0V” terminal, so that only one electrode is connected. In addition, the use, model, range and installation environment of the product must be fully considered during the installation process. For example, current sensors should be installed whenever possible to dissipate heat. In addition to installing wiring, immediate calibration and calibration, and paying attention to the working environment of the current sensor, the following should be noted to ensure the accuracy of the test:
1) The primary side conductor should be placed in the center of the inner hole of the current sensor, and should not be biased as far as possible;
2) The primary side line should be completely filled with the inner hole of the current sensor as far as possible, leaving no gap; 3) The current to be measured should be close to the standard rating IPN of the current sensor, not too large. If the conditions are limited, only one current sensor has a high rating, and the current to be measured is much lower than the rating. To improve measurement accuracy, the primary side line may be wound several times to bring it close to the rating.
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