US1116566A - Electric switch. - Google Patents

Description

R. H. CONRAD.

ELECTRIC SWITCH.

APPLICATION FILED FEB.2,1914.

Patented Nov. 10, 191%v WITNESSES: I a yfl zvz RANDOLPH H CONRAD, F OAKLAND, CALIFORNIA.

ELECTRIC SWITCH.

Specification of Letters Patent.

Patented Nov. 10, 1914.

Application filediebruary 2, 1914:. Serial No. 815,889.

To aZZ whom it may concern:

Be it known that I, RANDOLPH H. CON- min, a citizen of the United States, residing at Oakland, in the county of Alameda and State of California, have invented certain new and useful Improvements in Electric Switches,-of which the following is a specification.

This invention relates to improvements in electric switches and in particular to an automatic starting, overload and no-voltage release switch, for use in connection with current consuming device.

vl hile the description and illustration show the application to a three phase alternating current circuit it will be understood the. it may be used in two phase alternating, or three wire direct current.

The principal object of my invention is to provide means for opening the switch in all leads when one or more fuses blow, and thus prevent the motor taking current on one or two phase only, affording protection against overloads and line surges.

Another-object is by the same mechanism to open the switch when the voltage in one or more phase fails and so prevent the iniproper operation of the device.

Another object of my invention is to provide means for starting the motor or other device with the running fuses out of circuit, and automatically throwing them into circuit alter a predetermined interval of time. I

Other objects are: to throw out of circuit the coils governing the last mentioned switching device when the motor has been properly placed in circuit, to provide a visual signal to indicate the stopping of the motor, and in general to simplify switches oi the character named.

With these and other objects in view my invention consists in the new and novel C0111 struction and combination of parts as hercin described and point-ed out in the appended claims, and for a full comprehension of my. invention reference should be had to the accon'ipany ng drawings fornr ingr a part of this specification wherein,

Figure 1 is a diagrammatic or" my improved switch and the connection used therewith. Fig. 2 is a view in elevation showing the manner of connecting to the centcrpoint of the fuses.

Denoting corresponding parts by the same numerals of reference, 1 is a three phase -alternating current generator connected to the triple pole service switch 2 by conductors 3, 4c and 5 in which are the service fuses 6.

The protective fuses for the motor 7 denotedby 8, 9 and 10 are smaller in capacity than the service fuses and have one terminal of each connected by conductors 11, 12, and 13 with the three blades of switch 2. From the other terminal of each fuse, conductors l l, l5 and 16 are connected to the elcctroniagnet coils 17, 1S and 19 respectively. These coils are permanently mounted upon the three pointed yoke and each is provided with a. movable core 21, which cores are rigidly attached to a magnetically conducting member :22. Depending from the latter preferably in alinement with cores 21 are three blocks insulated therefrom and carrying adjacent their lower ends conducting strips 24, 255 and so. in alincment with these conducting strips are two pairs of contacts for each, denoted respectively by 27 and 28, and 30, 3.1, and These contacts are so arra i that the strips 21, 25 and :26 are below the lowest pair and as the cores 21 are drawn into the clcctromagnct coils, contact is made, first between the lower pair of contacts and then between the upper pair.

Connected to the center strip 23 is a rod which extends through a dash pot 434: having an annular contracted ring intermcdiate the ends thereof. Attached to rod within the dash pot is a piston 38 ha ving therein small openings 38. A valve disk 3. normally closes these openings and allow the upward passage of liquid but not the downward flow. The piston is of such diameter that it fits within the contracted portion 35 and allows the slow leakage thcrcbctwaen. Rod extends through the dash/pot and on the lower end has two projecting lugs 39 and lOof which the latter is thclonger. V

lilounted adjacent the dash pot in fixed relation thereto is'a retaining and tripping mechanism consisting of a bell cranl leve pivotally mounted as at 42 having arms l1 and Pivotally attached to arm 42 is a rod 13 at right angles to rod 33 and which slides freely through a slotted guide plate 44-, and which is provided with a beveled end 15 solenoid. coils l6 and A? having movable cores 4?) and 4L9 respectively, which are Above the arm 41 are two 119 fidepr'ess the arm to i the same pin 42 13 a second hell cranlr lever? having an arm 51, WillChIlOlXIlll-llff hes at right angle-s torod '33 and a curved. arm

. tached to the 52 projecting under, and- 'contactingwith arm 11. Dependingfrom arm 51 intermediate. the end and the pivotal point is a weighted arm 53, which actsas acounter weight to overbalancc arms 41 and 52. "At

lower end of 53 but eiectrically insulated therefrom is a contact strip 5% which makes contact. with conductor wires 55, 56 and 57, which are in: turn connected to the other terminals of coils 17, 18 and 19 respectiyely/ These coils are thus connected in star or "i relation across the three phases.

,One contact sprlng 28 is connected by conductor 58 to conductor 1% leading to the fuse 8 and theother by conductor 59 to one of the, motor terminals. Likewise one contact 30 is connected by conductor 60 to conductor 15 and fuse. 9, the other contact 30 by conductor 61 to the second terminal," and the first contact 32-is'connect'ed by a conductor 6 2', through conductor 16 to fuse 10, and the second contact by conductor 63 to the third motor terminal. lhe first' contact of pair 27, 29 and 31 are connected by conductor 64, 65 and 66 with the same terminai of fuses 8, 9 :1nd 10, respectively, to which the leads 11, 12, and 13 are attached and in each of these conductors is placed a resistance 67, The second contact spring of these pairs 27, 29 and '31 are connected by short conductors 68, 69 and 70 with conductors 59, 61 and 63 respectively, and'thus to the motor termil'lil S;

The fuses 8, 9,.and 10 are provided with spring contact clips 71, 72 and 73 respectively, uhich contact with the center point of the fuse. The manner in which this is preferably accomplished is illustrated in Fig. 2, wherein 74 is a fuse of the ordinary.

cartridge type having therein the main fuse wire 7 5. and the fine auxiliary or indicating wire 76, to indicate when the fuse is blown, andwhich is brought to the outside of the cartridge. This exposed' spot I use to contact with the spring clips. Clip 71 is con- .nected through conductor 78 with one terminal of coil 16, the other terminal of which is connected through conductor 82 to conductor 61 and thus through contacts 29 to fuse 9. Clips 72 and 73 are connected through conductors 79 and 80 with the two terminals of coil 47. In the conductors 7 8, 7 9 and 80 are lamps 81, Which'act as resist.- ances and as indicators. shows the parts positioned just after the main switch has been closed which establishes a circuit through cei lsr; d6 and d7,

with conductors 55, 56 and 57 causin'ihur piece 22 The drawing causing them to pull up their cores germ 1-1 to. he raised by the counterweight arm 53. This allows strip 5& to contac 1 rent to-flow from the service wires and 13 through fuses 8, 9'and'10 and 'c ductors 14,15 and 16, to coils 17, is and 19,

pulls up their respective cores and yoke. with the insulating strips; 23 at tached. Gonducting strips 2%, 25' and 26 bridge the spring contact pairs 27, 29 and 31 respectively. At the same time contact is madehetween these three pair of. contact springs, the dash pot piston 38 engages the annular rmg'35 and further upward motion takes place only as fast'as the liquid in the upper part' oi the dash pot can escape around the pistortznntil the lower part. The closing of these thjeepair of contacts completes the electrical conducting path from the switch 2 over conductor i1, -12 and- 13 to one terminal of the fuses 8, 9 ans :10

over conductors 1e, 15 and 16 to contacts 24, 25 and 26 and from thence over conductors 68, 69' and 70' to conductors 59, 61 and 63 respectively, to the three motor terminals. This gives -currentto the three phases of the motor without" the same passing through the protective fuses 8, 9 and 10 and the amount of current is kept down by the resistance in leads'6e,65 and. 66. It will be understood thatin place of resistance these leads may be carried through an'autostarter for the same purpose. Now after a predetermined respectively. The energizing of these coilsrespectively and from these same terminals V time whichis regulated by the passage of the liquid between the two sides of piston 38, the latter passes the annular ring 35 and the enlarged passage time createdv allows the cores 21 to move the attached parts quickly upward and blocks 24:, 25 and 26 to make connection between the pairs of contact springs 28, 30 and 32, at the same time opening the contact with the lower pairs. This upward movement is limited by the cores 21 coming incontact with the armature 20 at which time catch 39 has passed arm 45 by pushing it to the right and catch 40 has made contact with the under side of arm 51 lifting it upward and pulling contact plate 54; from the terminals of conductor 55, 5 6

and 57 thus opening the circuit through the.

operating coils 17; -18 and 19. Arm 45 slips under lug 39 and retains the rod 33 and: associated parts in their uppermost position.

The bridging of contacts 28, 30 and 32,;

completes the circuit from the service wires 1'1, '12, and 13 through fuses 8, 9 and 10 respectivcly; overwires 14, 15' and 16.; 58, 60 and 62, to contacts 28, 30 and 32;- over conductors 59, 61 and 63 to the motor'terminals. This places the motor inxcir'cuitifover the regular protective fuses and is-the normal running condition. The cells 46 and, e? as previously explained receive current from the center of the fuses so that the blowing of any fuse due to overload or the opening of any line will stop the flow of current in either of one or the other of these coils and allow the corresponding core to fall on the arm 41, pulling latch 43 from under lug 39, which allows yoke piece 29. and associated parts to fall by gravity and open all connection to the motor. The reason for connecting the fuse to the center point of the fuses is that if they were attached on the motor side of the, fuses they would receive current back through the motorin case a single fuse went out. The fact that the switch has opened is indicated by the extinguishing of one or more of. the lamps 8 1, which may be located at any convenient point, if desirable at a distance from the motor.

What I claim and wish to cover by Letters Patent is 1. An electric switch of the character described comprising a plurality of pairs of contacts, conductin blocks slidable between said pairs and a apted to make contact therebetween, electrically controlled means for moving said blocks successively into contact with said pairs of contacts, means for retarding said movement during contact with the first pair and permitting a quick movement to the second pair, means for holding said blocks in contact with said second pair and electrically controlled means for releasing said holding means upon failure of current, substantially as. described.

2. An electric switch of the character de scribed comprising a plurality of alining pairs of contacts, conducting blocks slidable between said pairs and adapted to make con tact therebetween, said blocksheing attached to but electrically insulated from a ma gnetically conducting yoke, solenoid coils adapted to operate said yoke to move said contact blocks successively between said pairs of contacts, a dashpot connected to said yoke to retard the movement thereof during the period when the said blocks are in contact with the first pairs of said contacts, a latch adapted to hold said yoke. in its uppermost position, means for opening the circuit to said operating solenoids when the yoke is latched, and electrically controlled means for unlocking said yoke upon failure of current, substantially as described.

3. An electric switch of the character described comprising the combination with- .1 three phase motor, a source of power therefor, conductors connecting said source to said motor, and fuses in said conductors, of,

blocks being attached to said yoke, a dashpot having its piston connected to said yoke to retard the motion thereof during the ieriod when the said blocks are in contact with the said first mentioned pairs of contacts, a latch adapted to hold said yoke in its uppermost position, two solenoids having free y moving cores, electrical connections' between said last mentioned solenoids and the center points of said fuses, means for causing the weight of said last mentioned cores to withdraw said latching means upon failure of current substantially as described 4. An electrical switch of the'character described comprising the combination with a three phase motor, a source of power therefor, conductors connecting said source to said motor and fusesin said conductors, of solenoids electr cally connected in star relation to said conductors, each solenoid having a freely moving core, said cores being connected to a common yoke, contact blocks.

carried by said yoke, electrically insulated therefrom, three sets of two pairs of electrical contacts adapted to be connected by said contact blocks, electrical connections from the first of said pairs to said conductors, said connections being made on opposite sides of said fuses, so as to short circu t said fuses when the said first pair is connected by said contact block, the second pairs being connected directly in said conductors, means for retarding the movement of said conductor blocks while'in contact with said first pairs of contacts, a latch for holding said contact blocks in engagement with said second pairs of contacts, solenoids having freely moving cores electrically connected with the center of said fuses, means connecting said freely moving cores with said latch whereby the weight of said cores may with draw saidlatch and means for opening the circuit to said first mentioned solenoid coils when theseicores have reached their uppermost position, substantially as and for the purpose described.

In testimony whereof I affix my signature in presence of two witnesses.

RANDOLPH H. CONRAD. Witn tsses a W. A. STOCK, R. M. OYARZO.

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