BG64574B1 - Star-delta switching element - Google Patents

Abstract

The invention refers to the star-delta switching element that allows for switch-on, start-up and operation of asynchronous electromotors and successfully replaces the existing versions of contractor combinations for control of asynchronous motors with the power exceeding 4 kW, which, however, does not limit its use elsewhere. The constructional concept of the switching element referred to in this invention provides for three independent positions, which is via the transmission elements transmitted into the contact section where the mobile support of flexible contacts with its movement closes the corresponding contacts, which first provides for electromotor power supply - star (Y) - with reverse connection to the star point, and upon the lapse of certain time, for power supply - delta (D). This is achieved in such a way that the driving element consists of two fixed armatures (1) bearing, attached with special loops (3), the coils (4, 5), separated by distance plates (6) that at the same time serve as a guide for the joint armature (2) with the opening (c) wherein fits the mobile metal support (7) in the way that the armature (2) is limited in its movement.

Description

Field of application

The invention relates to a star-triangle switch for switching on, starting and controlling asynchronous motors and successfully replaces existing variants of combinations of contactors for controlling asynchronous motors with a power exceeding 4 kW.

BACKGROUND OF THE INVENTION

Known solutions to a technical problem, such as starting and controlling motors with a power greater than 4 kW, include three standard contactors and a time-switch for a star-triangle switch. The correct operation of such an assembly is ensured by the proper connection with the wires of the power contacts of the three contactors.

A disadvantage of the known solution is that it is complex and is rarely applied to higher power motors as wires with larger cross sections are required.

A star-triangle switch described in WO1996 / 001486 and consisting of three parts is known, the movable part of the switch consisting of two coils with a common movable core and two fixed cores, as well as a movable metal support connected by a transmission lever support of contacts.

The disadvantage of this star-triangle switch is that it has a complex construction.

It is an object of the invention to provide a simple star-triangle switch applicable to higher-power motors.

SUMMARY OF THE INVENTION

This object is solved by the present invention by designing a switch that allows the combination of several contactor elements to be successfully replaced, in particular in solutions where one element can replace a combination of two or three contactors required in the known solutions, and by constructing a joint in which the supply and control sections between the contactors are properly connected to the wires so as not to damage or disrupt the assembly.

The design principle of the switch according to the present invention provides three independent positions, by means of transmission elements, which are transferred to the contact section, where by its movement the flexible support from flexible contacts closes the corresponding contacts. Initially, this provides power to the motor - star (Y) - with a reversible connection to the star's zero point, and after some time - provides power to the triangle - (D) - which corresponds to the rated voltage of the motor winding, two-stage start in the course of YD.

An advantage of the invention is that the contact system provides smooth operation and greatly simplifies traditional contactor combinations by using a sodium contactor and a time switch for a switch. The switching time can be adjusted and depends on the load driven by the engine and the starting position is signaled.

Description of the attached figures

The star-triangle switch according to the invention is explained in more detail by the examples and the accompanying drawings, where:

Figure 1 is a front view and cross-section of the star-triangle switch according to the invention;

Figure 2 is a longitudinal view and cross-section of a star-triangle switch according to the invention;

Figure 3 is a top and cross-sectional view of a star-triangle switch according to the invention;

FIG. 4 is a side view and cross section of a star-triangle switch according to the invention.

Exemplary embodiment and operation of the invention

In the star-triangle switch shown in the figures, the movable element consists of two fixed anchors 1 and one movable anchor 2. On the fixed anchors 1 are located coils 4 and 5, which are attached by special turns 3, each of the coils 4, 5 is in the on position, representing the on position of the switch according to the invention. Between them, the letter E is suspended by the movable anchor 2. It moves along side metal guides 6, which at the same time provide sufficient space for the fixed anchors 1. In the interrupted position of the coils 4, 5 the movable anchor 2 is inactive, which represents the third position of the element, i.e. excluded position. The movable anchor 2 transmits the force through the steel support 7 and through the transmission lever 8 to the movable support 9 of the flexible contacts 10, 11 and 12 in the contact portion of the switch.

The input fixed contacts LI, L2 and L3 are located on one side of the switch and the output fixed contacts Ul, VI, W1 and U2, V2, W2 are located on the other side, which is in accordance with the marking of the motor connecting plate. The contacts are covered with two insulating covers 31 which have openings for the connecting wires.

When the coil 4 is in the engaged position, the movable support 9 carrying the contacts 10, 11 and 12 is moved to position a. The load current flows from the input fixed contacts LI, L2 and L3, through the movable contacts 11 to the output fixed contacts Ul, VI, W1 and through the wires to the motor coil. The ends of the coil are connected to the fixed contacts U2, V2, W2, and the zero point of the star 13 is closed by the movable contacts 10. The motor coil is supplied with a voltage of 230 V (Y), and the motor rotor makes 2/3 nominal revolutions. After the start-up time has elapsed, the coil 4 becomes inactive and the coil 5 begins to act and causes the mobile support 9 to move with the contacts 10, 11 and 12 to position b. Then the zero point of star 13 opens and the current flows through the flexible contacts 11 and 12, through the permanent contacts Ul, VI, W1 and U2, V2, W2 and reaches the motor coil. At this point, the motor coil is supplied with a voltage of 400 V (D), which represents the rated voltage of the motor coil, and the rotor makes a nominal rpm and accordingly provides continuous operation.

The star-triangle switch is adjustable just like any traditional contactor, either by switch 01 only or by the ΟΝ / OFF button on the remote switch. It can be mounted on a standard support plate or fixed with screws.

Claims (8)

Claims A star-triangle switch, the movable part of which consists of two fixed anchors (1) on which coils are attached by special turns (3), and a movable metal support (7), characterized in that the coils (4 , 5) are separated by a spacer plate (6) which also serves as a guide for a connecting anchor (2) with an opening (c) in which the movable metal support (7) is placed to restrict the movements of the anchor (2). 2. Star-triangle switch according to claim 1, characterized in that the movable metal support (7) is vertically movable through the grooves of the frame (32) and at its lower part (14) is adapted for mounting a round head (15) ) on the transmission lever (8). 3. Star-triangle switch according to claims 1 and 2, characterized in that when mounting the coils (4, 5) to the anchor (1), the two removable windings (3) are trapped in the corresponding teeth (16) of the coils (16). 4, 5). 4. A star-triangle switch according to claims 1 to 3, characterized in that the transmission lever (8) is movable due to a circular dense central portion (17) for movement inside the semicircular sliding bearing surface of the frame (18). as well as in a sliding surface (19) fixed with a steel locking ring (20) in the frame groove, and two circular heads (15, 21) on the transmission lever side (8) are provided for the vertical movement of the moving parts and horizontal drag. 5. A star-triangle switch according to claims 1 to 4, characterized in that the contact system has two switches and one cut-off position, with three input fixed contacts (LI, L2 and L3) located on one side of the switch, and six output fixed contacts (Ul, V1, W1 and U2, V2, W2) are located on the other side in such a way that the double fixed contacts (22) have only one common connecting point (23) per phase. 5 6. Star-triangle switch according to claims 1 to 5, characterized in that the movable contacts (11) are fixed between the springs (24), and the zero point of the star (13), in view of their dual function. in an insulating chamber (25) so that it covers the three phase fields (26) triggered by specially formed movable contacts (10). 7. Star-triangle switch according to claims 1 to 6, characterized in that wires on the carrier wall (27) in one part of the control elements (28) and terminals are used to adjust the moving coils (4,5). (29), and the switch via springs (33) is in the neutral OFF position, ie. in the off position. 8. Star-triangle switch according to claims 1 to 7, characterized in that the covering part of the element (30) is for fixing the lateral covering insulating parts (31) to the fixed contacts (Ll, L2, L3) and (Ul , VI, Wl, U2, V2, W2) and their terminal openings are located in the corresponding grooves (32) of the frame.