Measuring principle of electromagnetic flowmeter the measuring principle of electromagnetic flowmeter is based on Faraday's law of induction Faraday's law of induction. When a conductive liquid flows in a magnetic field, it cuts magnetic lines of force and induces an electromotive force in the conductor (the liquid) , the magnitude of which is proportional to the velocity of the fluid. 12 in the electromagnetic flowmeter, the conducting medium in the measurement tube is equivalent to the conducting metal rod in Faraday's experiment, and two electrodes inside the tube measure the induced voltage. Since the size of the electromotive force is proportional to the average velocity of the liquid, the velocity of the liquid can be calculated by measuring the magnitude of the EMF. Combined with the cross-sectional area of the pipe, the flow rate (that is, the volume of fluid through the pipe per unit time) can be obtained. Electromagnetic flowmeters usually consist of two excitation coils and two electrodes, which generate a magnetic field through the measuring tube, and the electrodes are used to detect the induced potential and send it to the transmitter. The transmitter provides excitation current and processes signals to indicate flow or provide other output signals. Electromagnetic flowmeter is suitable for measuring liquid with enough conductivity, such as pulp and sewage, and will not cause additional pressure loss or cause wear, clogging and other problems.