Electromagnetic Type Flowmeters

• Electromagnetic type flowmeters work on the principle of faraday’s law which states that the induced EMF in any closed circuit is equal to the rate of change of magnetic flux through the circuit.
• E = dB/dt
• EMF is the force exerted on charged particles
• Change in magnetic flux can be done in many ways such as
• Moving a magnet towards and away from a circuit
• Rotating a circuit/coil inside a magnetic fiel
• By a conductor cutting a magnetic flux. The conductor will experience a change in magnetic flux in the circuit hence creating the EMF
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• Similarly, in an electromagnetic type flowmeter,
• The conductor is the liquid
• Coils are used to generate a gradient magnetic field
• As the liquid (conductor) flows, it will experience a change in magnetic flux, thus creating an EMF.
• The EMF generated is proportional to flow rate since a higher flow will experience a higher change in magnetic flux
• There will be an electrode which is used to pick up the voltage of the liquid with reference to ground
• Picture of Electromagnetic type flowmeter
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