US2872547A

US2872547A - High-speed electromagnetic switch

Info

Publication number: US2872547A
Application number: US662552A
Authority: US
Inventors: Edward J Diebold
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-05-29
Filing date: 1957-05-29
Publication date: 1959-02-03
Anticipated expiration: 1976-02-03

Description

Feb. 3, 1959 E. J. DlEBoLD 2,872,547

HIGH-SPEED ELECTROMAGNETIC SWITCH Filed May 29. 1957 5 Sheets-Sheet 1 i, li l! 'I' li INVENTOR,

il J1, i f EDWARD J. o/EBOLD.

TTORNEX Feb. 3, 1959 E. DIYEBOLD 2,872,547

HIGH-SPEED ELECTROMAGNETIC SWITCH Filed May 29, 1957 3 Sheets-Sheet 2 IIIIIIIIIIIII LAMINATIONS- INVENToR,

EDWARD D/EBULD.

A TTORNE )f Feb. 3, 1959 E. J. DIEBOLD 2,872,547

HIGH-SPEED ELECTROMAGNETIC SWITCH Filed May 29, 1957 3 Sheets-Sheet 3 INVENTOR,

EDWARD J. D/EBOLD.

A TTORNE Y United v'States Patent 2,872,547 HIGH-SPEED ELECTROMAGNETIC SWITCH Edward J. Diebold, Palos Verdes Estates, Calif., assgnor to the United States of America as represented by the Secretary of the Army Application May 29, 1957, 'Serial No. 662,552

6 Claims. (Cl. 2MP-93) 'I'his invention relates to an electro-magnetic switch and more particularly to such a switch which is compact and more easily assembled and adjusted than previous electromagnetic switches.

Electromagnetic switches can be described generally as comprising a ferro-magnetic and electrically conductive body of small size which is moved by magnetic forces between fixed magnet poles which also serve as electrical conductors. Magneti'zation of the poles attracts the movable body, establishing an electrical circuit between them. Demagnetization of the magnet poles releases the movable body which is carried away by another force, thus interrupting the electrical circuit. The electric current flowing through the circuit established by the movable body and the poles produces the magnetic field which provides the hold-in force; loss of this current releases the body.

Most prior electromagnetic switches having a high current capacity have tended to be bulky, heavy, and unduly complicated. ln many, there are a great number of loose parts, with fastenings or clamping means requiring much space and making the switch unwieldy to work with. The entire switch is usually made as a unit and adjusted once and for all. This makes the switch extremely diflicult to adjust and observe while in operation.

It is therefore an object of this invention to provide an improved electromagnetic switch which, for a given capacity, will be more satisfactory as to size, weight and simplicity than previous electromagnetic switches.

It is another object of the invention to provide an electromagnetic switch which is easy to assemble and can be adjusted more accurately, easily, and quickly both before and during operation.

fabricating the switch in two subassembliesv rather than These objects are achieved in the instant invention by in one assembly as has previously been done. One of the subassemblies is a closing magnet structure consisting of a magnetic core. The clamping means fastened to this core serves also as one current terminal of the switch. On this clamping body the closing point of the contact is provided by a closing buffer clamped to the current conductor by means of a copper clamping plate. The iron core of the closing magnet is surrounded by coils to magnetize it. When this combination of iron core, coils, conductor, closing buler and clamping plate is made as one assembly, it can be made structurally solid and operatively simple. All these units are mounted on a body portion made of a material which is relatively heavy and solid, such as brass.

The other subassembly is also made as solid and as compact as possible and contains an opening permanent magnet, magnetic laminations to energize the armature, and a copper conductor to carry the current to the contact, forming a solid metallic body for this opening magnet structure. On the solid body there are clamped an opening buffer, a buffer clamp plate, two clamper springs,

a guide spring and a main clamp. All these parts are 7 sandwiched and clamped together by four strong screws 2,872,547 Patented Feb. 3, 1959 v distance and angle of the opening assembly to the closing assembly.

For a more detailed understanding of the structure and functioning of the invention, reference is now made to the accompanying drawings wherein:

Figure 1 shows atop view of the improved electromagnetic switch.

Figure 2 is a section taken on line 1-1 of Fig. 1.

Figure 3 is a section taken on line 2 2 of Fig. l.

Figure 4 is an enlarged side View of the contact structure when the switch is open.

Figure 5 is an expanded view of the contact assembly.

Figure 6a is a side view of the opening magnet assembly.

Figure 6b is a bottom view of the opening magnet assembly.

Referring now more specifically to the drawings and especially to Figs. 1, 2 and 3 thereof, Fig. l is a top view of the assembled electromagnetic switch, Fig. 2 is a sectional view of Fig. 1 taken on line 1-1 thereof and Fig. 3 is a sectional view of Fig. l taken on line 2 2 thereof. The closing magnet coils are shown in Figs. l and 2 and are designated by the numerals 1 and 2. The body section of the closing magnet structure, on which the coils and the other elements of the closing structure are mounted, is made of a suitable conducting heavy material such as brass. This body section is composed of two parts called body halves. These two body halves are best seen in the sectional view of Fig. 3 and are designated as 3 and 4. The two body halves are joined by a screw such as shown at 5 and a lock washer 6, suitable holes being tapped in the body halves to accept the screw. Each body half has two brass body upstanding legs, these being shown at 7 and 8 in Fig. 2 and at 8 and 9 in Fig. 3.

Adjacent the upstanding body legs are two insulating spacers 10 and 11 and snugly placed between the two insulating spacers is the opening magnet assembly designated generally by the numeral 12. The contact assembly is shown generally as element 13. The specific features of the contact assembly and the opening magnet assembly will be described below.

A top insulating plate is shown comprising two

sections

14 and 15. The sections of the top insulating plate are shown attached to the brass upstanding legs by means of screws 16-19. The opening magnet assembly is held from the top insulating plate by means of two

screws

20 and 21 which are held constantly under pressure by

springs

22 and 23. The springs put the screw threads constantly under pressure, preventing possible play in the threads and any consequent vibration of the opening magnet assembly. In addition to keeping the permanent magnet assembly in place, the screws serve as an adjustment for the contact spacing. The contact spacing can be observed while the switch is in operation by means of mirrors 24 and 25. These two mirrors are inserted in the closing magnet assembly in suitable slots separating the brass body halves. The slots are milled in the brass body halves when they are fabricated and the mirrors are inserted when the switch is assembled. The purpose and functioning of the mirrors will be more fully explained hereinafter when the opening magnet assembly is described.

Inner pole pieces for closing magnet coils 1 and 2 are shown at 26 and 27. These pole pieces are composed of suitable laminated magnetic material. Outer pole pieces are shown at 28 and 29.

Elements

30 and 31 are sections of laminated ymaterial Vwhich connect Ythe inner and outer pole pieces. A suitable 'air gap 'for the 4inner pole pieces isprovid'ed 'as shown at32. Reference numeral 33 designates a hollow space in 'the body halves for the pole lpieces 26 and 27 and air gap 32. Since Fig. 3 is a sectional view, the

closing core laminations

30 and 31 are not shown in this figure, but it can be seen from Fig. 2 that the laminations are .placed in front of and behind the space 33 as seen in Fig. 3. ln Fig. 3` are also shown the closing magnet buler 34and the closing magnet buffer clamp 35. Buffere34 is preferably a straight piece of nickel-silver spring material whileclamp 35 may be any good conductor such as copper. As seen from the figure, buffer 34 and clamp 35 are joined tobr'ass body half 4 by means of screws 54.

The buife'r 34 and the copper buffer clamp 35 arethe only two yparts which are assembled to the closing magnet structure consisting of coils, cores, and brass body halves. The remainder of the necessary parts are located on the opening magnet assembly 'which is designated generally as numeral 12 in the drawings. A more detailed` view of the contact structure 13 is shown lin Figs. 4 and `Sfthe former showing a schematic side View of the structure with the switch in its open position and the latter showing an expanded view of the contact assembly. Fig. 4 shows clearly the relation of armature 12 to the laminations y26 and 27. Fig. 4 also shows the vvarmature 42 connected by means of the spring guide 37 to the upper conductor 36 of the opening magnet assembly. As seen in Fig. 4 and also Fig. 5, spring guide 37 is clamped between two damper guides 40 and these elements together with opening buffer clamp 38 and opening buffer 39 are held firmly in place by the armature spring clamp 41 which is screwed into the upper conductor 36. YIt is seen from Fig. 4 that the movement of armature '42 is limited to a very small travel which is approximately equal to the thickness of the spring guide up and down between the upper and lower magnets. This small amount of travel causes only low stresses in spring guide 37 and therefore reduces or eliminates fatigue breaks. Opening and closing huers 39 and 34, while they could be hat, are Ashown as slightly bent in Fig. 5. The slight bend in the buier plate permits clamping with the clamp in such a way that it adheres tightly to the magnet and does not vibrate loosely in the air. it is important to note, however, that the bend as shown in Fig. is exaggerated and is actually not as great as therein shown. This is also true of the damper guides 40.

A side sectional View of the opening magnet assembly is shown in Fig. 3 and it is designated generally as element l2. In this figure can be seen the opening permanent magnet 43 and opening core laminations 44 ofany suitable magnetic material to direct the iiux to the armature 4Z. Core laminations are also shown at 45. Rivets are shown at 46-49. The permanent magnet and the laminations are securely riveted together to form one compact assembly.

Side and bottom views of the opening magnet assembly are also shown in Figs. 6a and 6b. The side view is similar to the sectional View of Fig. 3. Reference numeral 55 designates a top clamp which contains threaded holes to accept screws and 21. From the bottom View it is seen that four screws S053 are used to clamp the Contact assembly to the upper conductor 36. From the bottom View it can also be seen that the spring guide 37 is of a triangular shape. The armature 42 is subjected to strong magnetic fields attracting it from side to side bending it across its thin dimension. It is seen that the spring guide itself is used as the contact element. In order to have a conductor and contact of minimum mass, the vcontactsurface-itselfris made large and iiat' to prevent damage due to the impact forces.

As lstated above, the armature moves with a very small travel equal to the thickness of the spring guide. The amount of travel can be observed by the mirrors 24 and which are built into the closing magnet structure as `described above. When looking into mirrors 24 and 25 from above for adjustment of the contact spacing, the picture observed appears similar to Fig. 4 and by comparing the amount'of travel of the armature to the thickness of the spring guide, the travel can be easily adjusted to `have the same magnitude. The contact spacing can be changed by adjusting the screws Ztl and 2l. Itis also important in operation that the armature travel parallel to itself, "i. Vejthat the closing buffer and the guide spring hit upon the whole surface at once and not more on one corner than another. The adjustment provided by the screws 2li and 21 permits this to be done accurately during operation.

The operation of the switch is as follows: When coils 1 and 2 are energized, armature 42 is attracted to the closing

coil pole pieces

26 and 27 and contact is made between buler 34 and spring guide 37, thus completing the switch circuit. When coils l and 2 are'deenergized,

armature 42'is attracted by the flux of the permanent magnet 43, thus opening the circuit.

The switch described is a high-speed type, adapted to operate primarily in rectifier and inverter circuits, which contact of the switch is made and broken at a high rate. A most serious problem heretofore encountered in high-speed electromagnetic switches used in these circuits is that of bounce, i. e., the tendency of the switch contacts, when operating at a high rate of speed, to vibrate in the open or closed position, thus causing faulty operation of the circuit in which the switch is used and also serious damage Vto the contacts. The electromagnetic switch of the instant invention has eliminated this problem due to the simple arrangement utilized whereby the contact operates between two metallic spring guide buiers which are clamped upon the magnets which attract the armature. `Apparently the shock of the spring guide upon the buffer plate is transmitted to the magnet and the buer plate bounces together with the contact plate. Thus, the bouncing between contact surfaces is completely eliminated.

Any undue stresses on spring guide 37 due to high speed operation are eliminated by the use of the dampers 40. Y A previously described, these are simple, straight spring blades which reduce the stress on the clamping point of the guide spring and also reduce random vibrations of the guide spring and introduce an element of friction which is beneficial to dampen Wild oscillations.

ObviouslyV many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. A structurally solid and compact electromagnetic switch containing a closing magnet subassembly, a rigid body member and an opening magnet subassembly, said closing magnet subassembly comprising closing core and coils and the closing terminal of the switch, said closing core, coils and terminal all mounted on said rigid body member, said opening magnet subassembly comprising an opening permanent magnet and poles therefor and the movable terminal of the switch, an armature of magnetic material carried by said movable terminal and normally held adjacent the poles of said opening permanent magnet, said opening magnet subassembly being adapted to tit in a recess provided in the rigid body member, with the closing terminal and the movable terminal of the switch in operative relation with each other.

2. A high-speed electromagnetic switch consisting of a closing magnet'subassembly and an opening magnet subassembly-,said closing magnet vsubassembly comprising a relatively heavy body portion containing two upstandpermanent magnet and clamping means serving as another current terminal of the switch, a combined movable contact and armature means held by the latter clamping means, said opening magnet subassembly being adapted to slide between the upstanding legs of the body portion of the closing magnet subassembly, with the armature means between said pole pieces and said laminations.

3. A high-speed electromagnetic switch comprising a closing magnet assembly and an opening magnet assembly, said closing magnet assembly comprising a closing coil with its associated magnetic core and pole pieces and a heavy, rigid body portion on which the coil and magnetic core are mounted, said rigid body portion being formed with two upstanding parallel legs, said opening magnet assembly comprising an opening permanent magnet, magnetic pole pieces and a magnetic armature, said magnetic armature being rigidly attached to one end of a iiat guide spring element, the other end of the guide spring element being rigidly attached to the opening magnet assembly, said opening magnet assembly being adapted to slide between the upstanding legs of the body portion, with the iinal operative position of the two assemblies being such that the magnetic armature lies between the respective pole pieces of the closing and opening magnet assemblies.

4. An opening magnet assembly for a high-speed magnetic switch comprising a permanent magnet, magnetic lamnations directing the flux away from said permanent magnet, a solid metal conductor rigidly attached to said permanent magnet and said laminations, a contact assembly including an opening magnet buffer, an opening magnet buffer clamp, a guide spring with upper and lower damper elements adjacent to said guide spring on upper and lower portions at one end thereof, an opening magnet clamp adapted to rigidly fasten said buffer clamp, guide spring and dampers to said solid metal conductor,

and a magnetic armature rigidly attached to the other end 'l of the guide spring and adapted to be attracted by the flux directed by the magnetic laminations.

5'. A structurally solid and compact electromagnetic switch consisting of a closing magnet subassembly and an opening magnet subassembly, said closing magnet subassembly comprising closing core and coils and the closing terminal of the switch all mounted on a rigid body member, said opening magnet subassembly comprising an opening permanent magnet and poles and the opening terminal of the switch, a recess provided in the rigid body member, said opening magnet subassembly slideably tting within said recess and being attached to said body member by screw means, with the closing terminal and the opening terminal of the switch in operative engagement with each other, the operative relationship between the terminals being adjustable by adjustment of said screw means.

6. A contact assembly for a high-speed electromagnetic switch comprising: an upper electrical contact, a lower electrical contact, a rod-like flexible guide spring, said upper electrical contact constituting one end of said guide spring, a magnetic armature mounted on said one end of said guide spring, an upper damper located above said guide spring and adjacent thereto on the other end thereof, a lower damper located below said guide spring and adjacent thereto on said other end, an opening buffer, a metal conducting plate, a clamp, said clamp maintaining in a close fitting relationship said conducting plate, opening buier, upper damper, guide spring and lower damper, a closing buffer adjacent to and above said lower electrical contact, said magnetic armature beingadapted to periodically connect the upper and lower contacts when said armature is periodically energized and deenergized.

References Cited in the file of this patent UNITED STATES PATENTS Re. 24,209 Bernstien Sept. 4, 1956 2,502,811 Willing et al. Apr. 4, 1950 2,504,101 Reifel Apr. 18, 1950 2,633,488 Brion Mar. 31, 1953 2,675,440 Reifel Apr. 13, 1954 2,729,726 Rudd Jan. 3, 1956 2,758,173 Riley Aug. 7, 1956