The working principle of Electromagnetic Flowmeters is rooted in Faraday's Law of Electromagnetic Induction. To elaborate, when a conductive fluid passes through the electromagnetic flowmeter, an induced voltage is generated within the liquid conductor. This generated voltage is directly proportional to the velocity of the conductive fluid, the magnetic flux density, and the conductor's width, which is the flowmeter's interior diameter. This induced voltage is subsequently detected by a pair of electrodes positioned on the flowmeter's tube wall. The formula for induced voltage is expressed as: U = K×B×V×D, where U represents the induced voltage, K stands for the instrument constant, B symbolizes the magnetic flux density, V signifies velocity, and D refers to the interior diameter of the measuring pipe.

Electromagnetic flowmeters are solely applicable for conductive liquid media. They boast extensive use in numerous diverse fields, including petroleum, chemical, metallurgy, water supply and drainage systems, steel, coal, paper, food, textile, environmental protection, and myriad other industries related to municipal administration and water conservancy construction, to name but a few.