SU1035659A1 - Device for switching-off ac and dc circuits - Google Patents

Abstract

A device for disconnecting the alternating and direct current circuits containing power contacts and cords, on the magnetic conductor of which two windings with a r number of turns are wound, characterized in that in order to expand the functionality and simplify the device, additional contacts and two high-resistance resistors, the windings of the throttles are connected in anti-parallel, power contacts are included in the small turn winding circuit, additional contacts are connected to the multiwinding winding circuit, both of the parallel connected high voltage circuits yucheny series with terminals for connecting the load, the power and auxiliary contacts zashunti- j Rowan high resistivity rezistoraSO mi. with SLE SP a 01 co

Description

The invention relates to devices for disconnecting alternating current and direct current circuits and can be used in electrical installations for various purposes, including in pulse technology. Known switching devices containing a contact system and an electromagnetic drive - automatic ABM 1. The disadvantage of these devices is low reliability. The closest to the proposed technical entity is a device for disconnecting the AC and DC circuits containing. The power contacts and the choke, on the magnetic conductor of which two windings with different numbers of turns of 2 W are wound. In this device, the chokes of the chokes are made of a magnet of hard materials and the chokes change the magnetic resistivity by 10. By that, being included in an alternating or pulsed current circuit, they, when changing the polarity of the current, form a zero current stage with duration at ,,, (1) where BC is the induction in the cross section of the magnetic conductor; o - section of the magnetic circuit; W is the number of turns; U, is the voltage of the magnetization reversal of drossel. . To provide a pause of current L1, sufficient for the switching device to operate, a large mass of throttles is required, which is the most expensive part of the device, since the cost of iron-nickel alloys is 20 times or more than the cost of electrical steels. A disadvantage of the known device is the complexity and limited functionality due to the impossibility of disconnecting TokoB variables at times when the current is not zero, as well as the impossibility of switching DC currents. The purpose of the invention is to expand the functionality. This goal is achieved by the fact that the device for disconnecting AC and DC circuits containing power contacts and a choke, on the MI Ghana magnetic circuit, has two windings with different numbers of turns, additional contacts and two high-resistance resistors, the windings of the throttles are connected in parallel to, in. the low-turn winding circuit includes power contacts, the multi-turn winding circuit includes additional contacts, both parallel-connected circuits are connected in series with the terminals for connecting the load, and the power and additional contacts are shunted by high-resistance resistors. Figure 1 is a diagram of a device for disconnecting an alternating current and a direct current circuit; Fig. 2 shows the current variation, f in the power contact circuit, when switching alternating current; on fig.Z - the same. when switching DC. . The device contains a low-winding winding 1 and a multi-turn winding 2 wound on the throttle magnetic core oppositely, a power contact system 3 and an additional contact system 4. The device is connected to a circuit supplying load 5 from an AC or direct current source. Contact pairs. Shorted by high-resistance resistors b. The magnetic system of the throttle is made of transformer electrical steel. The device works as follows. In the on state, windings 1 and 2 carry currents inversely proportional to the number of turns of windings 1 and 2, and due to counter-switching or counter-winding, the magnetic flux in the throttle magnetic core is absent, and the conductivity of two parallel-connected windings is equal to their active conductivity. According to the transformer 2, a current equal to J 2 flows where L is the current of the small turn coil; If the ratio of the number of turns of the windings 2 to the number of turns of the windings 1. When the contact system 4 is turned off, the multi-turn coil circuit opens and breaks the current -Jj which is much smaller than the current L; The inductance of the throttle jumpwise increases to the value of L, determined by the square of the number of turns, the size and magnetic permeability of the iron of the throttle magnetic circuit. The magnitude of L, and the size of the chokes, can be found if it is assumed that the voltage of the network is completely balanced. The EMF of the first winding of the choke connects. Then from the equation i% Aop SA, 3) With imeTOM that "uiL-AND can be neglected, we get t ()

where F is the angle — frequency of the network voltage;

the iniAon amplitude of the selected permissible current equation for arcless switching;

5, K is the cross section and the average length of the throttle cardiac;

 magnetic permeability of steel

When additional contacts 4 are opened, the current in winding 1 drops to O as a result of injecting an inductance L into the circuit. When alternating current is switched at time t, the power contacts of the switching device can be opened (Fig. 2). During the commutation of direct current, the power contacts 3 (Fig. 1) of the switching apparatus must disperse a sufficient distance in the intervals

; time i ,, (Фйг.З), determined by the permissible value of the current KOMMYTHpyeMoil-o.

The proposed device makes it possible to disconnect the direct and alternating currents in any part of the current curve by reducing the switched current to a level provided by its arc-free switching. Since the magnetic core of the throttle device is made of cheap transformer steel, its cost is reduced many times in comparison with the known devices. Thus, by switching small currents in the multi-turn circuit of the windings of the throttles, significant currents in the power circuit are reliably switched.

i, it

Phi1.

Claims (1)

A DEVICE FOR DISCONNECTING AC AND DC CIRCUITS, containing power contacts and a cross-wire, which has two windings with a different number of turns on the magnetic circuit, characterized in that, in order to expand the functionality and simplify the device, additional contacts and two high-resistance resistors, throttle windings are connected in parallel, power contacts are included in the low-turn winding circuit, additional contacts are included in the multi-turn winding circuit, both circuits connected in parallel The sequence with the pin for connecting the load, the power and auxiliary contacts zashunti- g Rowan high resistivity resistors. Qut. 1 a SU., „1035659>