US1642227A - bremner - Google Patents

Description

Sept. 13, 1927.

F. D. H. BREMNER BLOW-OUT ARRANGEMENT FOR ELECTRIC SWITCHES Filed Aug. 19, 1925 2 Sheets-Sheetl Jrrmysr Se t. 192

p 7 F. D. H.'BREMNER BLOW-OUT ARRANGEMENT FOR ELECTRIC SWI'ITCHES Filed Aug. 19, 1925 Z'SheetSPSheetZ ATTORNEY Patented Sept. 13, 1927.

UNITED STATES PATENT OFFICE.

FRANCIS DONALD HOLDEN BREMNER, OF LONDON, ENGLAND, ASSIGNOR TO .THE ENG- LISH ELECTRIC COMPANY LIMITED, OF LONDON, ENGLAND, BRITISH COMPANY.

BLOVV-OUT ARRANGEMENT FOR ELECTRIC SWITCHES.

Application filed August 19, 1925, Serial No. 51,202, and in Great Britain September 12, 1924.

There are many cases where an electric switch has to break a current of considerable magnitude in a location where it is difiicult to provide the space necessary for drawing out and extinguishing the arc. These cond1- tions arise more particularly where a number of such switches have to be grouped together as, for example, in the case of multiple unit traction equipment using motor coaches where it is usual to mount the switches controlling the motor circuits of each coach in the space beneath the floor of the coach. In this instance, the total available space is limited and in addition to that it is desirable or convenience of actuation to group the switches as close together as possible.

The present invention deals with the difiiculty above indicated and consists in pro viding that the principal part of the drawing out and extinguishing of the arc is performed by an auxiliary switch which can be located at a reasonable distance away from the main circuit breaking device and is brought into circuit by the small are produced at the contacts of the main circuit breaking device.

The invention will now be described by way of example with reference to the ac companying diagrammatic drawings of which Figure 1 shows in elevation the contacts and are destroying arrangement of a main switch one side of the arc chute being removed and Figure 2 shows on the left side a part sectional plan on the line II-II of Figure l and on the right side a part plan. Figure 3 shows in elevation portions of an auxiliary switch, including the contacts and the arc destroying arrangement, one side of g the arc chute being removed, and Figure 4 shows a section on the line IVIV of Figure 3. Figures 5 and 6 show views similar to those shown in Figures 3 and 4 of a modified construction of an auxiliary switch and Figure 6 is a section on the line VI-VI of Figure 5. Figure 7 shows a diagram of connections for two main switchesand an auxiliary switch. The main switch (Figures 1 and .2) is arranged with are horns 1 and 2 in a chute 3 and provided with blow out coil 1 and pole faces 5, but these members are of materially smaller dimensions than would be required if the whole extinction of the are which occurs upon opening contacts 6 and 7 were to be performed therein, since the energy to be dissipated within chute 3 each time the arc is broken is a comparatively small part of thatpresent in the usual arrangement.

The main switch contacts 6 and 7 are shown in their closed positions into which they have been moved from the open position due to the energizing of coil 27 of solenoid 31 which consequently lifts its armature 32 and communicates this motion to the moving contact 6 by way of connecting rod 47 and member 16 which is pivotally connected at 28 to a fixed conducting member 34. As soon as the coil 27 is'de-energized the armature 32 will fall (assisted by a biasing force such as a spring if required) and will cause the moving contact 6 to move to the left. Current enters the main switch at terminal 35 and passes through the winding of the blow-out coil 4 to the conducting member 34 to which the horn 1 is conductively fixed. The current thenpasses to the moving and fixed switch contacts 6 and 7 and to the fixed conducting member 29, to which the horn 2 is conductively fixed, and out at the terminal 30.

To establish connection with the auxiliary switch additional horns or electrodes 8 and will be quite independent of the main. circuit,

except when an arc exists, but where a single electrode is used one of the horns 1 and 2 of the main switch will be permanently connected with a contact of the auxiliary switch.

Electrodes 8 and 9 are preferably arranged with a barrier 10 of insulating material, for instance soapstone, placed between them, and projecting as at 11 from their inner ends, so as to draw out the arc of the main switch between them. Electrode 8 is elec trically connected through the cable 20 with one contact of the auxiliary switch, and electrode 9 is electrically connected through cable 36 with theother contact of the auxiliary switch, and the contacts 12 and 13 of the auxiliary switch Figures 3 and 4 are normally closed, so that the establishment of the circuit through them by the arc is accompanied by the extinction of that por ,tion of the are which is bridged by the circuit including the contacts of the auxiliary switch.

The auxiliary switch shown in Figures 3 and 4 is so arranged that as soon as current passes through it the contacts 12 and 13 are separated, thus producing an are which strikes onto horns 14 and 15, and travels outwards on them until it is extinguished, this action being assisted by a powerful magnetic blow-out. extinction of the are at the auxiliary switch is accompanied by the extinction of the partial are or arcs at the main switch.

The cables and 36 in Figure 1 are connected respectively to the terminal lugs 37and 38 in Figure 3 so that current passes from the additional electrode 8 in Figure 1 through the coil 17 of the blow-out device in Figure 3 to lever 24, moving and fixed contacts 12 and 13, terminal 38 and back by way or cable 36- to the additional electrode 9 in Figure 1. The arcing horn 14 is conductively connected through the member 33 to the inner end of the coil 17 and the other horn 15 is conductively connected to the fixed contact 13 and the terminal lug 38. In Figures 3 and 4 the current passing through the blow-out coil 17 is utilized not only to energize the core 18 and cheeks 19 of the blow-out magnet for the are between contacts 12 and 13 but. also for attracting an armature to operate the switch. This operation is carried out by providing on the iron circuit of the blow-out magnet aprojection or preferably a pair of projections 21 through whichpasses a small leakage field in which is located an armature 22, coupled by nonmagnetic spindle 23 to lever 24, on which is mounted moving contact 12 of the auxiliary switch. Armature 22 will usually be kept of small dimensions so as to restrict the leakage field. In order to assist in producing the rapid and cer tain opening of the auxiliary switch the connection between contact 12 and armature 22 may include a pin and slot connection or equivalent free motion device. For instance spindle '23 may be formed with slot through which passes lever 24 which is pivoted at 26, so that armature 22 moves an appreciable distance before giving movement to lever 24, and the armature has attained considerable velocity and reached a strong part of the attracting field before spindle 23 contacts with lever 24 and starts rotating it aboutpoint 26 to open contacts 12 and 13.

The auxiliary switch shown in Figures 5 and 6 difiers from that shown in Figures 3 and 4 in being provided with a blow-out coil which is energized from a source distinct from the current which has to be- It is obvious that the interrupted. This coil is denoted by the numeral 39 and its terminals 40 and 41 are connected to some suitable source of current. The current to be interrupted passes from the cable 20 (Figure 1) to the terminal 42, through the coil 43 of a solenoid device for operating the moving contact 12, to the lever 24 connected to that contact and thence to the fixed contact 13 and to terminal 44 which is connected to the cable 36 in Figure 1. The energization of the coil 43 causes the armature 45 of the solenoid device to rise together with the stud 46 to which it is connected. This stud then hits the lever 24 which rises and takes with it the contact 12 and so opens the contacts 12 and 13' of this auxiliary switch. The arcing horn 14 is conductively connected to the contact 12 by way of the lever 24 and the horn 15 is conductively connected to the fixed contact 12. The magnetic cheeks 19 are associated with theblow-out coil in the usual manner.

It will be seen that in many cases where a number of main switches are grouped together, but not intended to be opened simultaneously, a single auxiliary switch can be used in conjunction with them, the additional electrodes being connected in parallel. Fig. 3 shows two main switches '47 and 48 (which may be similar to Figure 1) each of which has its additional elec trode 8 connected through blow-out and operating coil 17 of an auxiliary switch (which may be similar to Figure 3) to its moving contact 12' whilst electrodes 9 are connected to stationary contact 13.

The invention is not limited to the precise arrangements shown in the drawings which are susceptible to many modifications. Obviously. where a single auxiliary switch serves a large number of main switches which are being continually brought into action for opening the circuit, it may be advantageous to have the auxiliary blow out continuously energized as for example in Figure 5. In this case, some independent means of opening the auxiliary switch must be provided, such, for instance as a separate series electrode-magnetic device (as for example in Figure 5) or a device utilizing the electrodynamic action of the field produced by the blow out coil upon a conductor carrying the current which flows to the auxiliary switch.

lVhat I claim as my invention and desire to secure by Letters Patent is 1. A blow out device comprising a main circuit breaking device, an auxiliary switch 7 separate from the said main circuit breaking device, conducting. means tor carrying arc current between the main circuit breaking device and the auxiliary switch, said means being adapted to be brought into circuit by an are at the main circuitbreaking device which is initiated by the normal functioning of said device when commencing to open the circuit, and means associated with the auxiliary switch "for stopping the flow of are cur rent therethrough.

2. A blow out device comprising a main circuit breaking device, an auxiliary switch, means for blowing out an are at said auxiliary switch and means for connecting said auxilia 5* switch in series with the main circut breakng device by way of an are at the main circuit device which is initiated by the normal functioning of said device in com mencing'to open the circuit.

A blow out device comprising a main circuit breaking device adapted to produce an are when commencing to break the circuit, means for breaking an are at said circuit breaking device, an auxiliary switch, means for blowing out an are at said auxiliary switch, means for connecting said auxiliary switch in circuit with the main circuit breaking device by way oi the said are breaking means so as to bridge the break produced in the arc. thereby.

l. A blow out device comprising a main circuit breaking device adapted to produce an are when commencing to break the cir cuit, an electrode lying in the path oi the are produced at said circuit breaking device, an auxiliary switch, means for blowing out an are at said auxiliary switch and means for connecting said auxiliary switch in circuit with said main circuit breaking device by way of said electrode.

A blow out device comprising a main circuit breaking device, arcing horns on the main circuit breaking device between which an arc is established by the normal functioning of said device when commencing to break the circuit, two electrodes arranged between the arcing horns, an insulating barrier placed between the electrodes and projecting beyond theirinner ends, an auxiliary switch, means for conveying arc current between the said electrodes and the auxiliary switch, and means associated with the auxiliary switch for stopping the flow of arc current therethrough.

(3. A blow out device comprising a main circuit breaking device adapted to establish an are when commencing to break the circuit, an auxiliary switch separate from the main circuit breaking device, means for conducting arc current between the main circuit breaking device and the auxiliary switch, and combined means for opening the contacts and blowing out the arc of the auxiliary switch upon the flow of arc current therethrough.

7. A blow out device comprising a main circuit breaking device adapted to establish an are when commencing to break the circuit, an auxiliary switch, means for conveying are current between the main circuit breaking device and the auxiliary switch, a blow out magnet on the auxiliary switch, an armature adapted to be influenced by the blow out magnet and opening means acting on a contact of the auxiliary switch and actuated by the said armature.

8. A'lilow out device comprising. a plurality of main circuit breaking devices, each one of which is adapted to establish an are when commencing to open its circuit, a single nxiliary switch, means for conducting arc current between each main circuit breaking device and the auxiliary switch, and means associated with the auxiliary switch for stopping the flow of arccurrent therethrough.

9. A blow out device comprising a main circuit breaking device adapted to establish an are when commencing to open the cir- 'cuit, an auxiliary switch, means for conduct ing arc current between the main circuit breaking device and the auxiliary switch, means including a coil influenced by arc current for opening the auxiliary switch and a blow out coil on the auxiliary switch, which coil is energized by current from a separate source of supply.

In testimony whereof I afiix my signature.

F. D. H. BREMNER.

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