Faraday’s law of electromagnetic induction states that an inductive voltage is generated when a conductor moves through a magnetic field. This principle is used as the basis of flow measurement in the RBEF electromagnetic flow meter.  In the electromagnetic flow meter, the flowing fluid corresponds to the moving conductor as described in Faraday’s law.

U_E ∞ B * D * v

The induced voltage UE is directly proportional to magnetic field intensity (B), electrode spacing (D) and average fluid velocity (v). Since magnetic field intensity (B) and the electrode spacing (D) are constant values, induced voltage U_E is therefore directly proportional to the average flow velocity (v).

Q = (∏ * D2) / 4 * v     therefore    U_E ∞ Q

The equation for calculating volumetric flow rate (Q) shows that the induced voltage (UE) is linear and directly proportional to the average velocity (v).  In the  flowmeter transmitter, the induced voltage (UE) from the electrodes is used to calculate volumetric flow rate (Q) based upon the pipe’s internal diameter.

U_E = Induced voltage

B = Magnetic field strength

D = Electrode spacing

V = Fluid velocity

Q = Instantaneous volumetric flow rate