Method for judging the quality of coils
The inter-turn impact withstand voltage tester has four typical automatic inspection and judgment methods. Users can combine or use each method individually according to the actual situation of the tested coil. Each judgment method allows for arbitrary setting and modification of the critical judgment threshold to achieve the purpose of accurately and quickly checking and judging the quality of different coils. The specific inspection and judgment methods are as follows:
1.4.1 Waveform Area Comparison (AREA SIZE)
Within any specified interval, the waveform areas of the standard coil and the measured coil are compared.
As shown in Figure 1.4.1, calculate the area within the A-B interval and determine the extent of the difference in the areas of the two.
The criteria for judgment are set in terms of percentages (％). Products that fall within the calculated range are considered qualified.
The size of the area within the interval is roughly proportional to the energy loss within the coil. Therefore, this can be used to determine the magnitude of the energy loss.
For instance, when there is an inter-turn short circuit in the tested coil, the reflected phenomenon is an increase in energy loss.
1.4.2 Waveform Difference Area Comparison (DIFFERENTIAL AREA)
Within any specified range, the area of the waveform deviation of the standard coil and the measured coil is compared with the area of the waveform of the standard coil.
As shown in Figure 1.4.2, calculate the area difference within the A-B interval and compare it with the standard waveform to determine the degree of deviation.
The criteria for judgment are set in terms of percentages (％), and the products within the specified range are considered qualified.
The size of the waveform deviation area represents the total sum of the inductance value and the degree of energy loss.
This method can comprehensively examine the inductance L value of the coil and the energy loss.
1.4.3 Waveform Corona Quantity Comparison (FLUTTER VALUE)
Within any specified range, compare the corona discharge quantity of the tested coil with the set value.
As shown in Figure 1.4.3, the waveform differences are largely ignored. Within any specified A-B interval, only the high-frequency components contained in the actual waveform of the tested coil are detected for area (integration) calculation, and the calculated results are compared with the set value to determine whether the corona discharge quantity is qualified.
It can be considered that this quantity represents the value detected through the high-pass filter in the analog mode.
1.4.4 Waveform Phase (Zero Crossing) Comparison
Within any specified interval, the oscillation periods of the standard coil and the coil under test are compared.
As shown in Figure 1.4.4, for any specified A-B interval, calculate the oscillation period of the measured coil waveform within that interval, and compare it with the oscillation period of the standard waveform within the same interval. Use the percentage of these two quantities as the basis for judgment, and the benchmark is set using percentages.
Since the oscillation period of the waveform is closely related to the inductance L of the coil, this method can focus on checking the inductance L value of the coil.
Post time: Feb-07-2026