RU77105U1 - ELECTRIC HEAT RELAY - Google Patents

Abstract

Electrothermal relays are used to protect three-phase asynchronous motors from current overloads of unacceptable duration. The technical result of the proposed electrothermal relay is to simplify and increase the efficiency of regulation of its operation by controlling the failure currents by remotely returning the relay to its original (operating position) from any control point. The electrothermal relay contains a housing, thermocouples, a contact mechanism, means of transferring movement to the contact mechanism, a node for adjusting the failure current and a return button. In this case, a remote return unit for electrothermal relay to the operating position, made in the form of a direct current electromagnet, is introduced into the electrothermal relay. The electromagnet is attached to the electrothermal relay and is activated when the set currents are exceeded for no more than 4 minutes, acting on the contact mechanism and returning the relay to working condition. 1 n and 3 z.p. f-ly, 2 ill.

Description

The utility model relates to electrical engineering, in particular to low-voltage apparatus engineering, and may find application in devices for protecting three-phase motors from current overloads of unacceptable duration, including arising from the loss of one of the phases.

In industry, electrothermal relays of the PTT series are quite widespread. However, when the electrothermal relays are triggered, after the function of protecting the electric motor and disconnecting the voltage in the main circuit, the electrothermal relay is returned to its original (working) position by manually pressing the return button directly located on the electrothermal relay itself, which significantly reduces the time and speed of switching on electric motor and is a significant drawback of these relays. Operators need to leave their workplace.

Known electrothermal relay PTT 5 (SU 434506, H01H 61/04, publ. 06/30/1974). The relay contains a housing, thermocouples, movable strips, a lever for highlighting the difference in the travels of the free ends of thermocouples, which serves to transfer movement from the movable planks to the contact mechanism, a node for regulating the failure current, a temperature compensation unit, an operation indicator pointer, and a manual return button.

The main disadvantages of such a relay are the excessive complexity of the node adjust the failure current and temperature compensation. As well as manual control of the relay enable button when disconnecting an unacceptable duration.

Closer to the proposed is the electrothermal relay PTT 3 (RU 2313153, H01H 61/04, publ. 20.12.2007), comprising a housing

thermocouples with leads, a contact mechanism, means of transferring movement to the contact mechanism, as well as a node for regulating the failure current, a node for temperature compensation, and a manual return button.

The disadvantage of this electrothermal relay is the rather complicated relay adjustment, as well as the possibility of only manual control of the failure current control unit after short-term current interruptions with unacceptable overload.

The objective and technical result of the proposed solution is to simplify the regulation of the operation of the electrothermal relay by creating the ability to control failure currents by remotely returning the relay to its original (working) position.

The technical result is achieved by the fact that in an electrothermal relay containing a housing, thermocouples, a contact mechanism, means of transferring movement to the contact mechanism, a node for adjusting the inoperative current, a return button, it is proposed to introduce a device for remotely returning the inoperative current to the unit for remotely returning the thermal relay to its working position in the form of a direct current electromagnet.

In this case, the remote relay return device in the form of a DC electromagnet is mounted on a common bracket together with an electrothermal relay.

In addition, a device for remotely returning an electrothermal relay to a working position after a failure current contains an electromagnet, including a coil frame on which a wire is wound, a core located in the central hole of the coil frame, coil output, to which voltage is supplied that controls the electromagnet.

Also, the remote relay return device in the form of an electromagnet is placed on a bracket connected on one side to an external rotary valve-type armature acting on the return button of the electrothermal relay by pressing and releasing it using a spring.

The essence of the proposed solution is illustrated by the attached drawings: figure 1 shows a schematic representation of an electrothermal relay with an electromagnet assembly; figure 2 shows the same image with the closed (working) position of the contact node.

The proposed device is a relay, consisting of 2 parts: an electrothermal relay 1 and a device for remotely returning a relay in the form of a DC 2 electromagnet. The nodes and details of the electrothermal relay 1 are mounted in a plastic housing 3. Housing 3 is divided into four cells (shown by a dotted line), three of which contain thermocouples (not shown) with leads (in figures 1 and 2), are closed by a plastic housing, and in the fourth cell in the breakaway shows a part of the contact mechanism containing a contact pair with one movable contact 4 and the other stationary, a reset button 5, and a regulator 6 for setting the tripping currents. At the same time, the range of regulation of the failure current, depending on the rated current of the electric motor, is set using the setpoint regulator 6 located on the housing 3, on which the range of the failure current (not shown) is marked. On the bracket 7, screws 8 are attached to the unit of the electromagnet 2 to remotely return the relay 1 to its original (working) position with closed contacts 4 connected to the reset button 5. The electromagnet 2 has a frame 9, on which an enameled wire 10 is wound and pressed with a premix to exclude the possibility of damage to the winding of the wire 10 during operation.

On the same bracket 7, on which the electromagnet 2 is fixed, the electrothermal relay 1 itself is fixed with screws 11.

The voltage for controlling the electromagnet 2 is supplied to the terminals 12 of the electromagnet coil. Through the Central hole of the frame 9 of the coil of the electromagnet passes the core 13, chased from the opposite side on the bracket 14, which attracts the external rotary anchor 15 of the valve type, located on the bracket 14. The anchor 15 presses the button 5

return and closes the contacts 4 (figure 2) electrothermal relay. The return of the anchor 15 to its original position is carried out using the spring 16.

The electrothermal relay is designed to operate when exposed to mechanical or climatic factors.

The operating position of the relay in space is any. It is preferable to mount the relay vertically with the lid up.

The relay provides operation in continuous, intermittent, continuous and intermittent modes.

Remote return of the relay is provided using the electromagnet return 2, operating in short-term mode.

The relay is calibrated by the value of the rated failure current of the average setting and cannot be recalibrated during operation.

At any position of controller 6 of the setpoint, relay 1 returns to its original position when electromagnet 2 is turned on, after at least 1.5 minutes. after relay 1 is activated.

Opening contact 4 allows the deviation of the operating current in normal switching mode and passage through closed contact 4 of the switching current relay for no more than 0.1 s. The relay return time when triggered by a load of 6 times the rated fault current is not more than 4 minutes.

In order to provide centralized control of the electric motor, in case of urgent operational control, an electromagnet 2 is fastened to an electrothermal relay 1, which operates in a short-term mode, which provides remote return of an electrothermal relay to its original (working) position after its operation by directly pressing the return button 5. Remote return of the electrothermal relay 1 is carried out from any place (control room, operator's room, control point, etc.) when voltage is applied to the terminals 12 of the coil connected by an electric circuit to a control button located at the operator's place.

The considered electrothermal relay is intended for use in control circuits of electric drives in alternating current circuits with voltage of 500 V, frequencies of 50 and 400 Hz, in direct current circuits with voltage of 440 V. The electromagnet is controlled by both alternating and direct current.

The technical result of the proposed solution is to simplify and increase the reliability of the operation of the electrothermal relay in intermittent mode with frequent starts and stops.

The electrothermal relay contains an element of remote kinematic communication between the sensing element - the core of the electromagnet and the on-off switching device, which performs the function of a return mechanism and is made in the form of a contact pair 4, which fixes the on-off position of button 5 (in working and non-working - static position).

This solution simplifies the design and increases the reliability of the electrothermal relay in the protection of controlled motors. Remote control also increases the efficiency and convenience of staff.

Claims (4)

1. An electrothermal relay comprising a housing, thermocouples, a contact mechanism, means for transferring movement to the contact mechanism, an inoperative current adjustment unit, a reset button, characterized in that a device for remotely returning an electrothermal relay to its operating position is introduced as a unit for adjusting the inoperative current in the form of a direct current electromagnet. 2. The electrothermal relay according to claim 1, characterized in that the remote relay return device in the form of a DC electromagnet is mounted on a common bracket together with an electrothermal relay. 3. The electrothermal relay according to claim 1, characterized in that the device for remotely returning the electrothermal relay to the operating position after the inactivity current contains an electromagnet including a coil frame on which a wire is wound, a core located in a central hole of the coil frame, coil output, which are supplied with voltage controlling the electromagnet. 4. The electrothermal relay according to claim 1 or 3, characterized in that the remote relay return device in the form of an electromagnet is placed on a bracket connected on one side to an external rotary valve armature acting on the electrothermal relay return button by pressing and releasing it with springs.