The importance of the coil resistance of the magnetic flow meter cannot be overstated as it’s essential in determining if a flowmeter is good or bad. Visual inspection and the instrument method both are used to determine if the wire insulation, sensor’s excitation coil resistance, ground resistance, and other items meet the standards. The specific detection methods are as follows:
(1) The values between the line number “7” and “8” should be between 30 and 170 ohms. If it matches the factory record, the coil is deemed good, which in effect indicates a good magnetic field strength of the flowmeter.
(2) In determining the dampness of the sensor, measure the resistance of the coil insulation to the ground with line number “1” and “7” or “8”. The value should be greater than 20 megaohms.
(3) Measure the contact between the electrode and the liquid with measurement line numbers “1” and “2”, and “1” and “3”, which would also give the indirect evaluation of the general condition of the electrode and the lining surface. It examines if the deposition is attached to the electrode surface and the lining layer. Moreover, it examines its conductive or insulating character. The reading should be between 1 kiloohm to 1 megaohm, and the values of the wire numbers “1” and “2”, and “1” and “3” should be roughly symmetrical.