US1253210A - Contact making and breaking device. - Google Patents

Description

L. W. CHUBB.

CONTACT MAKING AND BREAKING DEVICE.

APPLICATION FILED "M13. 1915.

1,253,210. Patented Jan. 15, 1918'.

35 45/ WITNESSES: INVENTOR a 4M leggy/i ll [0& m0 v I ATTORNE UNITED STATES LEWIS W. CHUBB, OF EDGEWOOD PARK,

HOUSE ELECTRIC AND MANUFACTURING SYLVANIA.

PENNSYLVANIA, ASSIGNOR TO WESTING- COMPANY, A COBIORATION or PENN- CCNTACT MAKING AND BREAKING DEVICE.

Specification of Letters Patent.

Patented Jan. 15, 1918.

Application filed May 3, 1915. Serial No. 25,587.

To all whom it may concern:

Be it known that I, LEWIS W. CI-IUBB, a citizen of the United States, and a resident of Edgewood Park, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Contact Making and Breakin Devices, of which the following is a speci cation.

My invention relates to contact making and breaking devices and particularly to such as are employed in voltage regulators, ignition devices, and similar apparatus.

The object of my invention is to provide means whereby the relatively movable contact terminals of an interrupting device may be relieved of injurious burning or arcing and of the resultant depositing and pitting.

It has heretofore been customary to connect a condenser in shunt to the contact terminals of circuit interrupters for the purpose of receiving the discharge of the energy in the circuit which occurs when the members are separated. However, with such an arrangement, arcing and burning at the contact members is not entirely avoided because the condenser discharges its charge through the contact members when they are again brought into engagement. When a condenser has suflicient capacity to effectively absorb the arc, it is generally also of suflicient capacity to produce a su stantial discharge when the contacts reengage, and this discharge causes a depositing and pitting of' the metal contacts, and, in some cases, causes the members to weld together. In fact, with any value of condenser capacity connected between the contact members, there is a certain amount of arcing and pitting of the members If the condenser capacity is low, the trouble appears as a burning arc, and, if the capacity is high, it appears as a depositing and pitting of the contact members.

According to the present invention, I propose to avoid the bove-mentioned difliculties by providing means whereby the condenser may receive a charge, as usual, when the contact members are separated and whereby the condenser is discharged through a high resistance, rather than through the contact members, when they reengage.

My invention is illustrated in the accompanying drawings, Figure 1 of which is a diagrammatic view of a part of a voltage regulator in connection with which it is employed. Fig. 2 represents a modified form of the device in which the controlled cir cult is entirely interrupted by the'separation of the contact terminals. Fig. 3 represents the invention employed in connection wlth a rotating commutating device. Fig. 4 illustrates another modification of the device employed in connection with an electromagnet, and Fig. 5 represents still another modified form of the invention in which an asymmetric cell is employed instead of an interrupting device.

The invention may be conveniently employed in connection with a voltage or similar regulator of the type in which the regulation is efiected by rapidly opening and closing a circuit in shunt to a resistor 1 (Fig. 1) that is included in circuit with field-magnet winding 2 of an exciter or other dynamoelectric machine, the opening and closing of the shunt circuit being efi'ected by means of stationary and movable contact terminals 3 and 4, the latter being actuated by means of an electromagnet 5 the circuit of which may be controlled in any suitable manner, such as by the main control element (not shown) of a voltage regulator. A circuit is provided in shunt relation to the contact terminals 3 and 4 which includes a condenser or a plurality of condensers 6 of suitable capacity, and a high-resistance device 7 that is connected in parallel therewith and is of the proper value to receive and dissipate the discharge from the condenser 0r condensers 6. The shunt circuit also includes an auxiliary pair of contact terminals 8 and 9 whereby the circuit may be made and broken. The contact member 9 is actuated into and out of engagement with the terminal 8 by means of an electromagnet 10 that is connected between the contact terminals 3 and 4, and also in shunt relation to the resistor 1.

When the contact terminals 3 and 4 are in engagement, as shown, the winding 10 has no potential applied to it because it is shunted by the said terminals. The contact members 8 and 9 are, consequently, also in engagement, and the condensers 6 are connected in shunt to the contact terminals 3 and 4. Upon separation of the members 3 and 4, the energy of the circuit is discharged into the condensers 6 because the contact terminals 8 and 9 cannot separate immediately, although full potential is applied to the electromagnet ior the reason tha he inductance of the clectromagnet introduces a certain delay or retardation. However, the terminals 8 and 9 are separated shortl after the separation of the terminals 3 an 4, with the result that the condenser discharges through the highresistance device 7 Upon reengagement, therefore, of the terminals 3 and 4, the condenser is already discharged and disconnected and there is, consequently, no burning or sticking of the contact members. Upon reengagcment of the members 3 and 4, the clectromagnet 10 again becomes deenergized, and the contact terminals 8 and 9 are agaln brought into engagement. The apparatus continues to operate in this manner.

It will be noted that, in Fig. 1, the clrcult in shunt to the resistor 1 is never completely interrupted because the electromagnet 10 1s permanently connected in shunt tolt. In some cases, a complete interruption of the circuit is desirable, and, in Fig. 2, I have illustrated a device in which this result is produced. The apparatus of Fig. 2 comprises a contact member 12 that is vibrated in any suitable manner, as by means of an electromagnet 13, and a contact member 14 that is adapted to be engaged by the member 12 and to be reciprocated through a shortv distance by the vertical movements of the said member. The terminal '14 is carried by a bracket 15 that is so mounted upon a stationary support 16 that it may reciprocate 'vertically and will remain in any position to which it is adjusted. To this end, the bracket may be provided with slots 15 and may be secured to'the support by means of screws 15 that project through the bracket slots and are adjusted to provide a suitable amount of friction between the parts. The

downward movement of the bracket is effected by engagement of the terminal 12 with the terminal 14, and its upward movement is effected by engagement of an armature 17 that carried the terminal 12 with an extension 18 of the bracket, an insulating block 19 being carried by the armature 17 to insulate it from the bracket. The lower end of the contact terminal 14 is also adapted to' engage a resiliently mounted contact terminal 20 that is connected to corresponding terminals of a resistor 21 and a condenser 22 that are connected in parallel with each other, the other corresponding terminals of said devices being connected to the contact terminal 12. The contact terminal 12 is connected to one side of the circuit to .be controlled or regulated, and the bracket 15 is connected to the other side of the said circuit.

In the operation of this device, the upward movement of the armature 17 causes the bracket 15 to occupy its uppermost position and thereby separates both pairs of contact terminals. The circuit to be controlled or regulated is, therefore, interruptconnecting the resistance 21 and the condenser 22 in shunt to the contact terminals 12 and 14. As the contact terminal 12 moves upwardly, it first disengages the terminal 14, thereby interrupting the regulated or controlled circuit at this point and causing the energy of the circuit to be absorbed in the condenser 22. Upon further upward movement of the terminal 12, the insulating block 19 engages the extension 18, and the contact terminal 14 is caused to disengage the ter minal 20, whereupon the circuit in shunt to the terminals 12 and 14 is interrupted and the condenser is caused to discharge through the resistance 21, thereby relieving the contact terminals 12 and 14 of any arcing thatmight result from the discharge of the condenser.

My invention may also be employed in connection with a commutating device having rotatable segments, as shown in Fig. 3, in which one terminal of the circuit to be interrupted is connected to a brush 25 that bears continuously upon a conducting ring 26, and brushes 27 and 28 that are connected to the other side of the circuit to be interrupted engage alternately with insulating and conducting segments 29 and 30, respectively. The resistance 31 and the condenser 32 are connected between the brushes 27 and 28, and the direction of rotation of the commutating device is such that the brush 28 is the leading brush. The conducting ring 26 is connected with the conducting segments 30. As the commutating device is rotated, the regulated circuit is first interrupted by disengagement of the brush 27 from one of the conducting segments, and the energy of the circuit is then absorbed in the condenser 32. Shortly thereafter, the brush 28 dis ngages the conducting segment, and the condenser discharges through theresistance 31. This arrangement is also such that the regulated circu1t is completely interrupted at the commutating device.

In Fig. 4, I have illustrated the invention as employed in connection with an electromagnet comprising an energizing winding 34, a core member 35 having a bifurcated pole, and two separately movable armatures 36 and 37 that are disposed respectively-opposite the pole projections of the core 35. One of the pole projections of the core is surrounded by a closed circuitedcoil or conductor 38 for the purpose of retarding the changes of flux therein. The armatures 36 and 37 respectively carry contact terminals 39 and 40 that are adapted to engage corresponding stationary contact terminals 41 ,and 42. The contact terminals 39 and 41 are connected to the two sides of the circuit to be interrupted, and a resistor 43 and a condenser 44 are connected between one side of said circuit and the contact terminal 42. The contact terminals 39 and 40 are also connected together.

In the operation of this device, the contact terminals 39 and 41 are first separated'because the flux is not retarded in the righthand pole projection of the core of the electromagnet. The separation -of the terminals 40 and 42 is delayed somewhat by reason of the employment of the closed circuited conductor 38, with the result that the energy of the interrupted circuit is discharged into the condenser 44 and is then dissipated in the resistor 43, as in the other ses.

In Fig. 5, the circuit in shunt to the main contact terminals includes an asymmetric cell or resistor 46, as well as a resistor 47 and 5 a condenser 48. The arrangement is such that when the contact terminals are separated, the energy of the circuit may be discharged into the condenser 48, while the asymmetriccell or resistor 46 prevents a flow 3g of current in the direction required to permit of discharging the condenser through the contact terminals. The condenser is, therefore, caused to discharge through the resistor 47 after the contact terminals have again come into engagement and the potential difi'erence between them has been reduced to zero. I prefer to use an electrolytic cell 46 having one filming electrode or a mercury vapor valve which will allow current to pass in but one direction.

It will be understood that any other device than a condenser may be employed if it possesses capacitance or the ability to receive the charge of the circuit after the separation 5 of the contact members. For this purpose, a storage battery or polarization cell may be employed, or even a body having inductance of the proper value. An impedance device may also be employed in place of a strictly 50 non-inductive resistance device as the device or circuit into which the charge of the capacity device is discharged and dissipated.

I claim as my invention: 1. The combination with cooperating contact members, and means for causing them.

to engage and disengage, of anon-oscillatory circuit including a capacity device and a discharge path connected in parallel with each other and in shunt to the contact members, and means for closing the said circuit after the engagement of the said contact members.

2. The combination with cooperating contact members, and means for causing them to engage and disengage, of a circuit 1n shunt to said contact members including a capacity device and a discharge path connected in parallel, and means for closing the said circuit after the engagement of said contact members.

3. The combination with cooperating contact members, and means for causing them to engage anddisengage, of a circuit in shunt to said contact members including a capacity device and a discharge path connected in parallel, and means for opening said circuit after separation of said contact members and for closing it after their reengagement.

4. The combination with main cooperating contact mem ers, and means for causing them to engage and disengage, of a circuit in shunt to said contact members including a capacity device and a dischargepath connected in parallel, auxiliary contact members adapted to open and close said circuit, and an electromagnet for actuating the auxiliary contact members and'connected between the main contact members.

5. The combination with main cooperating contact members, and means for causing them to engage and disengage, of a circuit in shunt relation to the said contact membersincluding a condenser and a discharge path connected in parallel, auxiliary contact members, and an electromagnet connected between the main contact members and adapted to open the said auxiliary contact members after the separation of the main contact members and to close them after the reengagement of the main contactmembers.

6. The combination with main cooperating contact members, and means for causing them to engage and disengage, of a circuit in shunt to said contact members including a capacity device and an energy-consuming device connected in parallel, auxiliary contact members, and means for closing the auxiliary contact members after the main contact members are closed.

7 The combination with cooperating contact members, of a non-oscillatory circuit connected in shunt to the contact members .and comprising parallel-connected capacity and energy-consuming devices, and means for opening the said non-oscillatory circuit after the separation of the said contact members and for closing it after their reengagement.

8. The. combination with cooperating contact members, of a capacity device connected in shunt to the contact members, and means for opening the circuit of the capacity device after the separation of the contact members and for closing it after their reengagement.

9. The combination with cooperating contact members, of a non-oscillatory circuit in shunt to' said contact members including a capacity device and discharge path connected in parallel, and means forvo said circuit after separation of the sald contact members and for closing it after their renga ement.

10. he. combination with cooperating main contact members, of a circuit 1n shunt to said contact members including a capacity device and an energy-absorbing device conning nected in parallel, auxiliary contact mcm- 10 contact members. In testlmony whereof, I have hereunto 15 igligcribed my name this 30th day of April LEWIS w. OHUBB.

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