JPH07240141A - Shunt circuit trip device - Google Patents

Abstract

PURPOSE: To provide a shunt trip device operable by a extremely little shunt current. CONSTITUTION: A shunt trip device is equipped with an armature 18 which is fitted to a ferromagnetic frame 12 so as to be pivot-movable. A U-shaped member 20 is fitted to the frame 12 via a non-magnetic spacer 30A. A first magnetic circuit is specified by the member 20, the pole 16 portion of the frame 12, and the armature 18. A second magnetic circuit is specified by the bridge portion 26 of a leg 22, and the member 20, together with the portion 14, 1, the pole 16 of the frame, and the armature 18. A third magnetic circuit is specified by the leg 24 and the bridge 26 of the member 20, the portion 14 of the frame 12 and the pole 16, and the portion of the armature 18 between the pole 16 and the leg 24. A coil 34 is supported by the leg 22 of the member 20, and a permanent magnet 22 is sandwiched between the portion 26 of the member 20 and the portions 14, 1 of the frame 12.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to shunt trip devices.

According to the invention, in a shunt trip device responsive to trip current, an armature displaceable between a first closed position and a second open position and the armature from a first position to a second position. A ferromagnetic frame including a pressing means for pressing and a support to which the armature is pivotably mounted; a first magnetic circuit together with the armature, and a first pole piece defining member; Magnetic circuit defining means for contacting the pole piece defining member when the armature is in the first position and spaced apart from the pole piece defining member when the armature is in the second position; First magnetic field generating means for generating a magnetic flux in one magnetic path, second magnetic circuit defining means for defining the second magnetic circuit together with the pole piece defining member and the support, and together with the support A third magnetic circuit defining means that defines three magnetic circuits and does not pass through the pole piece defining member; and a second magnetic field generating means that generates magnetic flux in the second and third magnetic circuits. A shunt trip device is provided.

A spacer member may be provided in the third magnetic circuit to change the magnetic resistance of the circuit in a predetermined manner.

The first magnetic circuit defining means may have an air gap between a portion of the first magnetic circuit defining means and the armature.

The first magnetic field generating means may be a coil through which a trip current flows.

The second magnetic field generating means may be a permanent magnet.

The first magnetic circuit defining means includes a "U" shaped ferromagnetic member, one of its legs defining a pole piece,
It is advantageous to place the coil around this leg.

The support may be a column to which the armature is pivotably mounted, the free legs of the "U" shaped members being fixed to this column by spacers.

The frame also has a base from which the struts may extend. In this case, the permanent magnet can be arranged between this base and the bridge of the "U" -shaped member.

It will be appreciated that the polarities of the coils are such that they are in the opposite direction of the magnetic flux provided by the permanent magnets.

Finally, the pressing means may be a helical spring that is tensioned and connected to the armature on the side of the strut opposite the pole pieces.

[0012]

In use, the armature is displaced to engage the pole pieces. The magnetic flux created by the permanent magnets of the second magnetic circuit is sufficient to keep the armature in contact with the pole pieces when no current is flowing in the coil. When sufficient current flows through the coil, some of the magnetic flux in the second magnetic circuit is transferred to the third magnetic circuit, causing the spring to displace the armature, thereby activating the tripping mechanism. The armature is reset by the reset mechanism and reengages the pole pieces.

By varying the air gap between the free legs of the "U" shaped member and the thickness of the spacer, the characteristics of the shunt trip device can be varied as desired.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described by way of embodiments with reference to the accompanying drawings.

In FIG. 1, the electromagnetic unit of the low energy shunt trip device is indicated generally by the numeral 10. The unit 10 has a mild steel frame 12 having a base 14 and struts 16 extending upwardly therefrom. Prop 16
Is located in the center, so the base 14 is located on the left side portion 1
It has a 4.1 and a right part 14.2. A mild steel armature 18 is pivotally mounted on the column 16. The spring 19 is connected between the right part 14.2 of the base and the armature 18. Since the spring 19 is under tension, the right part of the armature 18 is pulled down towards the base 14, which causes the armature 18
Pivot clockwise. The clockwise pivoting movement of the armature 18 is limited by tripping and resetting mechanisms not shown in FIG. The tripping mechanism is shown in FIGS. 2 and 3 and will be described later.

The unit 10 further includes a mild steel "U" shaped member 20. The member 20 has a left leg 22, a right leg 24, and a bridge portion 26. The leg 24 on the right side is supported by the screw 28 on the side opposite to the spring 19 from the column 16
It is fixed to. Spacer 30, which is a non-magnetic material, has legs 2
It is provided between 4 and the support 16. Leg 22 is leg 24
You can see that it is slightly longer. The free ends of the legs 22 are aligned with the tops of the stanchions 16 and the armature 18 pivots counterclockwise against the springs 19 so that the legs 2
Contact the free end of 2. When the armature 18 is in contact with the free end of the leg 22, the armature 18 and the leg 2
An air gap of approximately 0.5 mm is created between the four free ends.

The permanent magnet 32 includes the bridge portion 26 and the base 1.
It is gripped between the left side portion 14.1 and the left side portion 14.1.

The coil 34 wound around the bobbin 36 is attached to the leg 22.
It is provided in.

It will be appreciated that the legs 22 form the pole pieces. In addition, a "U" shaped member 20 defines the first magnetic circuit with the portion of the strut 16 adjacent the leg 24 and the armature 18, with the majority of the magnetic flux passing through the air gap between the leg 24 and the armature 18. It will be understood. This air gap is much smaller than the thickness of the spacer 30. Furthermore, the legs 22, the bridge portion 26, the left side portion 14.1 of the base 14, the columns 16 and the armature 18 define a second magnetic circuit. Finally, the leg 24, the bridge part 26, the left base part 14.1
And the strut 16 and the portion of the armature 18 between the strut 16 and the leg 24 define a third magnetic circuit, and the magnetic flux also passes through the spacer 30.

In use, the coil 34 produces magnetic flux in the first and second magnetic circuits and the permanent magnet 32 provides magnetic flux in the second and third magnetic circuits.

In use, in normal operation, no current flows through the coil 34. The magnetic flux provided by the permanent magnets 32 of the second magnetic circuit causes the armature 18 to contact the legs 22 when the armature 18 is displaced against the legs 22 against the spring 19 by a reset mechanism (not shown). Hold the state. This magnetic flux is itself an armature 18
Not strong enough to close. When a relatively small current flows through the coil 34, some of the magnetic flux is transferred from the second magnetic circuit to the third magnetic circuit, reducing the force holding the armature 18 on the leg 22 and causing the armature 18 to spring 19. Pivots in the clockwise direction, which activates the tripping mechanism of unit 10 (shown in FIGS. 2 and 3).

In the case of the unit as shown, 6V, 1
Applicants believe that a mA trip current is sufficient to trip the device.

Further, as described above, the holding force of the unit can be changed by changing the thickness of the spacer 30, and the magnitude of the trip current can be changed between the leg 24 and the armature 18.
It can be easily changed by changing the air gap between and.

2 and 3 the unit 10 is shown with a tripping mechanism 40 shown schematically. The tripping mechanism 40 is shown in the "tripped" state in FIG. 2 and in the "on" state in FIG.

The tripping mechanism 40 is the trip lever 4
2 has an armature 18, a cradle 44,
It is connected to the movable contact carrier 46 and the handle 48. The cradle 44 pivots about the pin 50 and has an extension arm 52. Tension spring 5
4 is connected between the arm 52 and the carrier 46 in a "centered" manner. The handle 48 has a nose 56 which engages and rides along the ramped surface 58 of the cradle 44 when the armature 18 and trip lever 42 are in the "on" position to ride this surface. Pivot to engage trip lever 42. Not shown is the mechanism for resetting the armature 18 and trip lever 42 described above to pivot them to the "on" position.

Those skilled in the art will readily appreciate that as armature 18 pivots away from legs 22, trip lever 42 also pivots, thereby releasing cradle 44. The cradle 44 and carrier then pivot from the "on" position of FIG. 3 to the "tripped" position of FIG.

[0027]

The present invention provides a shunt trip device that can be operated with a very low energy shunt current, and the features of the device can be changed in a simple and repeatable manner.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an electromagnetic unit of a low energy shunt trip according to the present invention.

FIG. 2 is a schematic diagram of an electromagnetic device shown with the tripping mechanism in a “tripped” state.

FIG. 3 is a schematic diagram of a tripping mechanism in the “on” state.

[Explanation of symbols]

 10 Electromagnetic device for low energy shunt trip 12 Mild steel frame 14 Base 14.1 Left base 14.2 Right base 16 Pillar 18 Mild steel armature 19 Spring 20 U-shaped member 22 Left leg 24 Right leg 26 Bridge 28 Screw 30 Non-magnetic body Spacer 32 Permanent magnet 34 Coil 36 Bobbin 40 Tripping mechanism 42 Trip lever 44 Cradle 46 Moving contact carrier 48 Handle 50 Pin 52 Extension arm 54 Extension spring 56 Nose 58 Cradle surface

Claims (12)

[Claims] 1. A shunt trip device responsive to trip current, wherein the armature is displaceable between a first closed position and a second open position and a push for pushing the armature from the first position to the second position. A first magnetic circuit defining a first magnetic circuit with the ferromagnetic frame and the armature, the means including a support to which the armature is pivotally mounted, and a first magnetic circuit defining the pole piece defining member. First magnetic circuit defining means for contacting the pole piece defining member when the armature is in the first position and spaced from the pole piece defining member when the armature is in the second position; and a first magnetic path. First magnetic field generating means for generating a magnetic flux, second magnetic circuit defining means for defining a second magnetic circuit together with the pole piece defining member and the support, and third magnetic circuit together with the support And a second magnetic circuit defining means for defining a magnetic field that does not pass through the pole piece defining member and a second magnetic circuit for generating magnetic flux in the second and third magnetic circuits
The shunt trip device, comprising: 2. The apparatus according to claim 1, wherein the third magnetic circuit defining means includes a non-magnetic spacer. 3. A device according to claim 1 or 2, characterized in that the first magnetic circuit defining means comprises an air gap. 4. An apparatus according to claim 3, wherein an air gap is between the armature and the element forming part of the first magnetic circuit defining means. 5. The device according to claim 1, wherein the first magnetic field generating means comprises a coil. 6. A device according to claim 1, wherein the second magnetic field generating means comprises a permanent magnet. 7. A device according to claim 1, wherein the first magnetic circuit defining means comprises a "U" shaped member, one of the legs of which constitutes a pole piece defining member. . 8. A support and a "U" fixed to the support.
Device according to claim 7, characterized in that it is one leg of a letter-shaped member. 9. The frame has a base from which a support extends and the second magnetic field generating means is disposed between the bridge portion of the "U" shaped member and the frame. The device according to claim 8. 10. The device according to claim 7, wherein the leg forming the pole piece defining member is slightly longer than the other leg. 11. The apparatus according to claim 1, wherein the magnetic flux generated by the first magnetic field generating means also passes through the second magnetic circuit. 12. A device according to claim 1, wherein the pressing means is a spring.