What is the test principle of coating insulation resistance measuring instrument for silicon steel sheet?
Testing principle:The circuit for measuring the insulation resistance of the MEGGP-205 silicon steel sheet is shown in figure. At the specified voltage and pressure, 10 fixed metal contacts are pressed on a coating surface of the steel plate. The effectiveness of the surface insulating coating is assessed by testing the current flowing through the 10 contacts. Each contact of the tester is supplied by a DC independent power supply. For each measurement, the bit voltage stability in the 500mV + 2.5mV, the current in the 01A range. The two spiral bits play the role of the current loop in contact with the sample metal substrate. Through the measurement of 10 current values of 10 parallel contacts, the surface insulation resistance coefficient can be calculated by using GB/T2522 - 2007, "the method of measuring the resistance between electrical steel sheets (strips) and the test of coating adhesion".
Test procedure:The specimen is placed between the specimen table and the 10 contacts and exerts 1290 Newton force. The current on each contact is measured by a power supply with a voltage stabilizing power supply. If the measurement is to evaluate the quality of coating insulation on one side, 10 contacts shall be used, 10 data from 10 representative areas of the steel plate or 10 measuring specimens.
Sample requirement:Each specimen shall consist of a sample or a sample band. The length and width of the sample shall be greater than the effective measuring area of the 10 contacts respectively. The test is destructive and the specimen can only be used once. In order to obtain a representative sample from the results, the entire width of the clipping plate, the sample surface should be clean, smooth, no scar, scratch.
