Method of judging complete demagnetization(1) In the process of rising and falling of voltage, the excitation current value of the same voltage is the same;(2)The waveform of the excitation current is symmetrical up and down, and there is no even harmonic component.

Ac method: apply 50Hz AC voltage between the low-voltage side of the tested transformer (such as generator, high voltage neutral point grounding). According to the power supply capacity, adjust the compensation capacitor C, reduce the power supply current, the low-voltage side of the test to reflect

DC method: according to the electrical theory XHXC105 demagnetizer is a direct current through the reverse direction, and gradually reduce, decrease the hysteresis loop of the core, to eliminate the purpose of residual magnetism. Direct current is passed into the high-voltage winding of the tested t

Due to the inherent hysteresis of ferromagnetic materials, residual magnetic remanence will remain in the iron core after the operation of the voltage ratio and DC resistance measurement of the power transformer. Because of the existence of remanent magnetism, when the transformer is put into operat

What is the starting current and starting torque of the motor when the inverter is used? The frequency and voltage are increased with the speed of the motor, and the starting current is limited to 150% rated current (125 / 200 according to the type of machine). When starting directly with power freq

When the motor is driven by a power frequency power supply, the voltage decreases and the current increases; for the inverter drive, if the voltage also drops when the frequency drops, does the current increase? When the frequency drops (low speed), if the output is the same power, the current incre

What is the difference between voltage and current? The main circuit of the converter can be divided into two types: the voltage mode is to convert the DC of the voltage source into the AC converter, and the filter of the DC loop is the capacitance. Current mode is a converter that converts the curr

What is a converter? Frequency converter is a power control device which converts the power frequency power supply to another frequency by using the on-off action of the power semiconductor device. What is the difference between PWM and PAM? PWM is the abbreviation of Pulse Width Modulation, which c

The expansion of the capacitor shell in operation is due to the dissociation of the insulating material inside the capacitor, the breakdown of gas or the breakdown of some elements into the discharge of the shell, etc., which increases the internal pressure of the sealed shell of the capacitor. Caus

(1) The relevant capacitors should be tested and checked, and the reasons should not be found out, and the electric power is not allowed to be forcibly transmitted after the fuse is replaced;(2) Pay attention to the standard of fuse installation and select the fuse with qualified quality;(3) The fus