Electromagnetic flow meter:
Principle: Electromagnetic flow meter works on the principle of Faraday’s law of electromagnetic induction which states that when a current carrying conductor moves through stationary transverse magnetic field, an emf is induced between the ends of the conductor and this emf. is proportional to relative velocity between the conductor and magnetic field. The induced emf is given by
E=Blv where E-emf
l-Length of conductor
B-Magnetic flux density
v-Velocity of conductor
Working: As the fluid flows through the pipe, due to magnetic field an emf is induced between the electrodes. The emf induced is proportional to the velocity of fluid. As the flow rate varies, velocity of fluid changes causing the induced emf to change.
Diagram: