- The instrument works on Faraday's law of electromagnetic induction. The magnetic field is generated around the measuring tube by the instrument. The fluid passing through the measuring tube generates a voltage. This voltage is directly proportional to velocity of the flow. Thus the flow is measured and displayed on the indicator. Mag-Flow 650 provides worry free flow measurement, which measures the flow of any conductive liquid flowing through it. It uses non-intrusive measurement element hence, debris/solids will not interfere with the measurement. Its rugged rubber lining provides outstanding electrical insulating properties. Mag-Flow 650 is well designed for industrial waste water and water industry.