US1927026A - Electrical relay construction - Google Patents

Description

Sept. 19, 1933. E. L. FONSECA ELECTRICAL RELAY CONSTRUCTION Filed Feb. 17, 1930 Pat en ted Sept. 19,

PATENT OFFICE 1,927,026 ELECTRICAL RELAY CONSTRUCTION Edward L. Fonseca, Newark, N. J., assignor to I The Wilcolator Company, Newark, N. J., a corporation of Delaware Application February 17, 1930. Serial No. 429,084

' 4 Claims. ((1200-1 17 This invention relates to electrical relays and has particular reference to the arrangement and construction of certain parts of direct current relays. I F

The principal objects of this invention are to provide novel means for eliminating the damaging effects of the arc which forms between the separating contacts of a relay, and also to provide a relay constructed in a novel way whereby ef-= ficient operation, simplicity of manufacture assembly, and low cost are obtained.

These and other objects are obtained in a ierred embodiment of the invention which consists in mounting upon the usual insulating base plate a pair of spaced members of magnetic terial which serve as supports for line resistance units or the like, and as poles for a magnetic arc blow-out, the field coil of which is mounted be tween these members, preferably below the contacts of the relay. Insulating these ma netic pole members from the arc and defining the magn tic air-gap are sheets of insulating material. he i ing these insulating sheets against the faces the pole members and spacing them apart is e of insulating material which is placed across magnetic air-gap in the path of the arc and which serves as an arc-splitter to prevent the from flashing back between the contacts or conducting parts.

accompanying drawing, in which Figure 1 illustrates in elevation one ment of the invention;

Fig. 2 is a front view thereof; and

Fig. 3 is an enlarged fragmentary cross-section thereof as seen along the line 3--3 of Fig. i.

In the drawing, numeral 10 designates the base of the relay, this base being formed of insulating material such as porcelain, composition, or any or the other usual insulating-materials. Mounted "2 a bracket ll secured. to the base 10 is the magt coil 12 of the relay, the core 13 of which projects upwardly for cooperation with the armature 14, which is in the form of a plate pivoted at one end upon pointed screws 15 secured in bracket ill.

The moving contact arm 16 of the relay is secured to so as to be movable by the armature 14 by means of a pin 17 mounted upon armature ltl,

this pin 17 carrying the washers 18 between which is mounted a coil spring 19. This coil spring 19 normally keeps the armature 14 and the contact arm 16 in engagement, although armature 14 and contact arm 16 are relatively movable. The rear end-of contact arm 16 is piloted in position by means of a screw 20 projecting through an oversize hole in the armature, this screw serving as a binding post for one side of the circuit controlled.

by the relay. The front end of contact arm 16 carries the movable relay contact 21 adapted to cooperate with the fixed relay contact 22. When relay magnet coil 12 is de-ener moving relay contact 21 is held separated i om fixed relay contact 22 by the coil spring 23 se=- cured at one end to the rear end of armature l i and at the other cruel to a pin 24. mounted upon the rear surface of bracket ll. The space be tween relay contacts 21 and 22 is less than the space between armature 14- and the core 13 of relay coil 12 when relay coil 12 is deenergized.

' This is done in order that a good, positive contact is made between relay contacts 21 and 22 when relay coil 12 is energy the a nature i l of the relay accordingly being 1 into engagement with core 13 through greater distance of .1, than the movement of contact 21 to "ed contact 22. will accordingly be e t when the relay is energized, armature ted slightly from contact arm 16 against in of spring 19, which has the additional. so effect of producing a sli ht wiping betwee'". contacts 2i and 22, whereby their engaging s faces lrept in good contacting condition all times.

Set in a transverse groove in the top sur 'c of base plate is and secured thereto are pair U-shaped brackets 25 which are forme of steel or some other good magnetic ina l.

brackets 25 serve as the poles for magnetic arc blcw ouathe field winding of wh ch is mounted in yoke 2'1 secured by sore". s or he like 28 to the brackets 25. The yoke 2'? caries the fixed relay contact 22 and the binding post 29, to which one terminal or the circuit con trolled by the relay is connected.

Insulating the relay contacts 21 and 22 the pole brackets 25 and defining the magnetic air-gap are a pair of insulating sheets 30 of mica or other good insulating material, these sheets being placed between the opposite sides or" yoke 2'3 and the corresponding surfaces of pole brack ets 25, as shown particularly in Figs. 2 and. 3h

Spacing and securing in place these mica sheets 30 is a rod 31 of refractory and insulating material, such as Rockbestos or other similar material, this rod 31 having tenon ends set in corresponding apertures through the mica sheets 30 and the pole brackets 25, as shownin Fig. 3. The rod 31 is placed in front of and slightly above the relay contacts 21 and 22 and serves as a mechanical arc-breaking agent or arc-splitter for the are formed between contacts 21 and 22 when they separate, this are being drawn forward by the magnetic field created between pole brackets 25 by the field winding 26. The arc, although drawn forward and blown out by the magnetic fleld flux between pole brackets 25, tends to flash back and maintain itself between relay contact 22 and some portion of the contact arm 16 or other metal part after the contacts 21 and 22 have separated. The flame of the arc tends to flash upwardly and back, but the rod 31 is so positioned that the flame cannot flash in this direction, but only in a forward direction, where it can do no harm and where it is eventually blown out by the magnetic circuit.

Mounted in brackets 25 are auxiliary electrical units 32, which, in the particular embodiment illustrated, are resistance coils insulated in porcelain or the like. These resistance units are of the commercial type, consisting of hollow porcelain tubes which are held in place in brackets 25 by means of rods 33 passing through them and tapped into the lower arms of brackets 25 so that the units 32 may be readily emplaced and removed. These resistance units 32 may be used for any purpose, such as reducing the current through the relay magnet winding 12 or the arc blowout winding 26 when the units are connected in series therewith, or for any other purpose. Although resistance units 32 have been illustrated and described, other electrical units might be used in a similar way, the pole brackets 25 serving as a convenient and efiective support therefor.

The novel relay of this invention operates similarly to relays now in use insofar as electrical action thereof is concerned, the energization of relay coil 12 causing the connection of armature 14 and core 13, with the consequent earlier and perfect, slightly wiping engagement of relay contacts 21 and 22. The relay contacts 21 and 22 remain closed as long as relay coil 12 is energized, but when the latter is de-energized, spring 23 pulls armature 14 away from core 13 about the pivot screws 15 and separates relay contacts 21 and 22. The usual are produced upon the separation of relay contacts 21 and 22 is drawn forward and blown out by the magnetic field flux formed across the air-gap between poles 25 by the magnetic winding 26. Frequently, however, before the arc is blown out, it flashes up and back to maintain itself between fixed relay contact 22 and some metallic part 0! the moving contact the relay contacts 21 and 22, so that the path of 21, such as the contact arm 16. In order to prevent the are from flashing up and back, it is broken or split mechanically by the refractory rod 31 placed slightly in front and slightly above the arc is lengthened to such an extent that before the arc can travel the added distance around rod 31 and back to the contact arm 16 or other metallic part, it is blown out by the magnetic held between poles 25.

It will be seen that the new relay 0! this invention provides many advantages over relays heretofore provided, principal among which is the effective are elimination without expensive or complicated parts, but, on the contrary, by few' and inexpensive parts which form important elements in the construction of the relay as a whole. For example, the arc spliter 31 serves as a spacer and support for the mica sheets 30, and the poles 25 serve as brackets for the electrical units 32, and form a generally compact unit which is inexpensive to manufacture and assemble, and which is not likely to get out of order.

I claim:

1. In an electrical device having separable electrical contacts and magnetic field poles mounted on opposite sides of the contacts for blowing out the are formed between them, the combination of an insulator on the face of each of said poles, and a member extending between said poles for securing said insulators to the faces of said pole and positioned adjacent the contacts in the direction of movement of the are formed between them for breaking the arc.

2. In an electrical device having separable electrical contacts and a pair of magnetic field poles supported adjacent the contacts, the combination of lateral extensions on said poles, and independent electrical units supported by said extensions.

3. In an electrical device having an insulating base, the combination of U-shaped brackets of magnetic material mounted upon said base and independent insulated electrical units mounted between the arms of each of said brackets.

4. In an electrical device having separable contacts and a base, the combination of members mounted on the base at either side of the contacts, an insulating sheet on the inner surface of each member, and a rod extending between the sheets 5 forsecuring them to the corresponding members and positioned in the path of the arc formed be tween the members for breaking the arc.

EDWARD L. FONSECA.

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