METHOD FOR REDUCING INRUSH CURRENT OF SINGLE-PHASE TRANSFORMER WHEN RE-ENABLING IN IDLE MODE Russian patent published in 2017 - IPC H02H9/00 

FIELD: electricity.

SUBSTANCE: device comprises a device for removing the residual magnetization of the magnetic circuit of the transformer, comprising a DC voltage source and a switch connected to the first terminal of said source voltage supply three parallel branches. The first branch - series-connected primary winding of the transformer and a shunt resistor, the second branch - two series-connected measuring resistor voltage divider, the third branch - the discharge capacitor. And parallel to the input terminals of shunt resistor connected to a recording device and data processing, and output terminals - in parallel to one of the measuring voltage divider resistors. The second DC voltage source terminal is connected to a common node of the three parallel branches. The device introduced additional switches, security device and a device for inclusion in a predetermined voltage phase control circuit, which comprises a thyristor, a diode, resistor, switching element, the starting key switch configured to switch in a phase 90° mains voltage. Input clamp switch control circuit connected to the negative pole of the power source through the starting key and two thyristors, the cathode of the first thyristor is connected to the anode of the second control passage and the cathode of the first thyristor are connected through resistors to the positive pole of the power source, and the control passage and the anode of the second thyristor are connected diode. Control transitions thyristors connected between a switching element, in synchronization with the mains voltage, wherein one of the additional switches is connected to the output shunt resistor and the primary winding of output transformer, and a second additional switch is connected with one of the resistors of the measuring voltage divider and a second terminal of the primary winding transformer. The load switching devices in a specified phase voltage used by the primary winding of the transformer. Start key is connected to the junction of three parallel branches with the ability to exclude short-circuit DC voltage outputs. In parallel, the switch from the input pins connected safety device.

EFFECT: increased efficiency reduce the inrush current.

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