SU721859A1 - Ac contactor with arcless switching - Google Patents

Description

one

The invention relates to low-voltage electrical apparatus, in particular, to switching devices with no arc switching.

AC contactors with arc-free commutation are known, containing main contacts, in parallel with which contactless controlled elements 1.1 j are connected.

The closest to the invention according to the technical nature is an AC contactor with a pyramide-free mutation, containing the main contacts, in parallel with which, contactless controllable elements with voltage regulators in the control circuits, and current transformers {connected in series with the main contacts and 2 .

The disadvantages of the known contactors are large dimensions and a high level of energy losses, resulting in a decrease in the tenderness of their work.

The purpose of the invention is to reduce the dimensions of the congactor and reduce the power of its heat loss. This is achieved with the fact that two transistors and two resistors are introduced into the proposed contactor. a mountain (trans) current transformers with partitioned secondary windings were used as current transformers, each of the secondary windings is made up of two sections connected according to sections and each of the transiators is emitter-collector connected to the control circuit of the contactless controlled element, and the base is connected to the voltage regulator directly and to the cathode of the anode, connected in series with the gap emitter-collector of this transistor, through a resistor.

Claims (2)

In the drawing, a diagram is given of an embossed AC contactor with an arc-free X 1mW (for one current direction). A current transformer 2 is connected in series with the main contacts 1 of the contactor and has two in series and according to the included sections 3 and 4 of the secondary winding (with the number of turns, respectively, W W HW (Section 3 through diode 5 is connected to the thyristor control circuit 6. In series with section 4) the diode 7 is connected to the transistor 8, the base of which is connected to the voltage regulator 9 directly, and to the cathode of the diode 7 through the resistor 10. The contactor operates as follows. In the on state of the contact, the network current (1 /) passes through the contact 1 and the primary winding of the current transformer. At the beginning of the half cycle of switching current to the angle. I arcsihW, where 44 is the number of turns of the secondary current transformer Iv is the thyristor control current (1 maximum control current by starting characteristic). If) - switching current amplitude, the secondary current transformer current passes only through section 3. When this voltage drop across the resistor 10 (C) is less than the stabilization voltage (UQ- ,. ) the voltage regulator, the base current of the transistor 8 is zero, and therefore the transistor is closed. The voltage across the transistor 8 (U) PrOblichOenno si aims at HvVj where R is the resistance of the resistor 1O. When the transistor 8 intercepts the active mode of operation. The secondary current of the current transformer begins to flow into the transistor and section 4. The voltage across the resistor U is stabilized at U (rf emf. In section 3 while also equal to U (-T as diode 5 is open. With some thyristor 6 fully opens, since the secondary current defined by two successively switched on seshshmi 3 is 94 times the current I y.Therefore, the emf in section 3 decreases to ba Uctvfv; The rate of change of magnetic induction in the current transformer at yoke 1 CCfj is is. -, dt Wj, S and on section B, UCT, dt where 5 is the trans section area Current current angle. The angles of the P – i or zones without the arc operation of the proposed one and the known contactors are equal.However, due to the smaller change in the magnetic induction in this scheme, the cross section of the current transformer and its curvature significantly decrease, which is especially significant for small contactors. a reduction in the power of heat losses in the circuit elements and, consequently, an increase in the reliability of the contactor operation is achieved. In the design of contactors, where the dimensions of transformers are not of great importance (for example, with a large volume occupied by thyristors), the application of the proposed scheme allows to significantly expand the zone of arc-free shutdown (,) of the contactor and, therefore, reduce the lower limit of the current to be disconnected when coaxing the required wear resistance and tetlite losses. Claims of the invention AC contactor with arc-free switching, containing the main contacts, in parallel with which are connected non-contact controlled elements with voltage regulators in the control circuits, current transformers connected in series with the main contacts, and the secondary windings of current transformers through diodes are included in the circuits control of contactless controlled elements, characterized in that, in order to reduce overall dimensions and reduce heat loss power, two transistors are embedded in it and two resistors, and current transformers with partitioned secondary windings were used as current transformers, each of the secondary windings made of two sections connected according to each other and each of the transistors connected by an emitter-collector gap to the contactless control circuit. element, and the base is connected to the voltage regulator directly 596 but also to the cathode of the diode connected in series with the emitter-collector gap of this transistor, through the Gore. Sources of information taken into account in the examination 1. US patent number 3330992, cl. 317-11, 1967. 2. Author's certificate of the USSR № 335728, cl. H O1 H 9 / ZO, 06.O1.72 (prototype).