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Analysis of the causes of electromagnetic loss of electromagnetic flowmeter

The electromagnetic loss of the electromagnetic flowmeter is for a variety of reasons. It may be caused by the interference of the magnetic field around it. It may also cause the signal transmission speed to interfere with the flowmeter's own structure. For whatever reason, the electromagnetic flowmeter of the electromagnetic flowmeter is generally used. Losses come in the following forms:

Hysteresis loss
Hysteresis loss is due to the hysteresis characteristics of magnetic materials. After the coil is connected to the alternating current, the magnetic flux phase lags the current phase by a certain angle (hysteresis angle) due to the hysteresis of the magnetic material. When the magnetic induction in the core does not reach saturation, the hysteresis loss is small. Therefore, the yoke and the iron core of the electromagnetic flowmeter are made of an electric steel sheet with high magnetic permeability, and the rolling direction of the silicon steel sheet is preferably in the same direction as the magnetic field line, so that the hysteresis loss is greatly reduced and can be neglected.

Eddy current loss
The eddy current loss yoke in the yoke should be a sheet with high magnetic permeability and low electric rate. Each piece should be insulated to reduce the loss. Usually, the commercial frequency of several tens of hertz, the thickness of the silicon steel sheet is 0.25~0.5. Mm can make the eddy current loss not exceed the allowable value.

Eddy current loss in metal measuring tube
The higher the frequency of the excitation power supply, the stronger the magnetic field strength, the longer the axial length of the magnetic field, the larger the diameter of the measuring tube, and the thicker the wall thickness, the larger the eddy current and the larger the eddy current loss, and the magnetic induction lags behind the field current. The phase difference angle is also larger.

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