US2334339A - Electric switch system - Google Patents

Description

Nov. 1 6, 1943. G. N. LEMMON 2,334,339

ELECTRIC SWITCH SYSTEM Filed Feb. 2, 1942 4 Sheets-Sheet 2 INVENTOR Nov. 16, 1943. G. N. LEMMON 2,334,339

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Filed Feb. 2, 1942 4 Sheets-Shed s INVENTOR Nov. 16, 1943. GJNQ LE MoN ELECTRIC SWITCH SYSTEM Filed Feb. 2; 1942 4 Sheets-Sheet. 4

lNVENTOR Patented Nov. 16, 1943 ELECTRIC SWITCH SYSTEM George N. Lemmon, Homewood, All, assignor to Southern States Equipment,0orporation. Birmingham, Ala.

Application February 2, 1942, Serial No. 429,154 (oi. zoo-s) 8 Claims.

The invention relates to automatic switches, and particularly to switches which automatically open the circuit only when permanent trouble has developed, but which do not open the circuit ii the trouble is merely transient.

One purpose is to provide a switch suitable for feeding one section or a circuit which is all fed through an automatic oil circuit breaker Another purpose is to provide a means whereby one long circuit can readily be subdivided into successive sections. Another purpose is to provide a device for opening a circuit ii and only when overload conditions have been immediately followed by no-load conditions for a predetermined number of times successively.

One form of device embodying the invention is shown in Fig. l; the control coil and mechanism of the device are shown in side view at Fig. 2; Fig. 3 is similar to Fig. 2 but with parts in the no-load positions; Fig. 4 shows in side view the switch-releasemechanism: and Fig. 5 is a front view of the mechanism with the cover 5 removed.

Another form of the invention which is suitable for operating a three phase air break switch is indicated in Fig. 6, which shows one unit 01' a three-phase switch. Fig. '7 is a diagram for one method of wiring the control circuits for the three-phase installation, and Fig. 8 shows the details of the overload notching devices.

As shown in Fig. 1, a base i supports the insulator 2 upon which are mounted the line terminal 3 and the pivotally movable switch arm 5. Upon the insulator 5 are mounted the other line terminal 8, the housing I with its cover 5, and also the latch which engages and holds in contact the switch arm 4. Within the housing I,

the mechanism shown in Fig. 2 is supported by the bolts 8, 9. Through the insulator ID the circuit goes from 5 through the housing I to the solenoid coil II, whose magnetic circuit includes the stationary parts i2, i3, and the movable parts i5, i5 which rock about the V hinge l6 and which are partially counter-balanced by the two springs II. The supporting block i5 is secured to l3, it provides recesses for two bolts 9. 5 and it supports by the screws |5--i5 the two side plates 20, 20' of the notching unit. Between the plates 25, 20' are the inertia wheel 2i on its pivot 22, the ratchet 23 on its pivot 24,

the notch wheel 25 on its pivot 26, the guide-bar 21 on its pivot 28, and the double ratchet-bar 25 which is pivotally connected at 30 with the rocker II, II. Figs. 2 and 3 show these parts, with plate 20 removed.

The arm Ii turns freely about the pivot 22 between the limits of the pins 53, which are set in the wheel 2i; a suitable spring 3i biases the arm 5i and the pin 55 towards one another; and the bar 32 is pivotally connected to II and to 21 so that it can travel approximately longitudinally. Another spring indicated by the arrow 35 biases the bar 32 in the direction indicated. The pin 55 in arm 32 is engageable with ratchet 25, and the roller 51 which is mounted on 52 rolls along one edge oi. the bar 29 or drops into the notch 55, due to the bias of spring 35. The ratchet II is pivoted at between the two sides of the bar 29; the rivet pin 42 spaces the the two sides of the bar 25 and also serves as a stop torthe ratchet I5: and a spring indicated by the arrow "biases 59 in the direction indicated. Theguide 4i spaces the two sides 25, 20', and serves also to direct the vertical travel of bar 25 and itsiratchet 59.

Figure 2 shows the parts at the top of their travel, the movable stop pin 44 acting to prevent l4, l5 from rising any closer to the core i2. Two guides 55, 45 guide the pin 45: the collar 51 is securely attached to the pin 44, and the spring 45 biases the pin 44 downwardly until the collar 51 comes against the stop 55. The bolts and nuts at 59 hold the stops 55, 45 and slots in 45 allow adjustment of 45 up and down, thereby changing at will the tension on the spring 55 without changing the positions of the pin 55.

A suitable spring, indicated by the arrow 25",

biases the notch wheel 25 counter-clockwise as indicated by the arrow, and as the wheel 25 rotates a pin secured to the wheel 25 travels through the slot 5| in the side plate 20. See

Fig. 3. The end of the pin 50 is beyond the plate 20 and is engageable with the tail oi. the latch 52, as shown in Fig. 4. The tail of latch 52 is offset so that the pin 50does not enter the plane occupied by 55, 55, 51, or 59. The pivots 55 and 54 are stationary and are supported inside the housing I. The linkage members 55, 55, and 51 are joined by the movable pivots 58 and 59, and the latch 52 engages with the end 56' of the member 56. The clevis 51 is part of the member 51, and the pivot 60 supports the latch 5| which is biased by a suitable spring in the direction shown by the arrow, the portion 5i acting'as a stop against the hub of the member 51.

The cover 8 carries a drip-groove l2 and two wing-guides 83 between which the upper end of the switch arm 4 is guided as the arm is closed. The upper end of the arm 4 has a projection 04 which is engaged and held by the latch 8|. The arm 4 is pivoted at 05 and the spring contacts 60 and 81 press outwardly against 4 biasing it clockwise around the pivot 85. A spring arm 69 is attached at 08 to the arm 51. The arm 51 has a projection 88 to which is secured the spring arm 09. This is in the same plane as the projection 10 of the arm 1| which is pivoted at 12.

Operation is as follows. Under no-load conditions the armature |4-|I is at its lowest position, shown in Fig. 3, and the ratchet-bar 28 is also down. When normal load comes on the line the solenoid II exerts enough pull to lift the armature I4II up. When I4 comes in contact with the stop pin 44 it encounters the pressure of the spring 48, which is sufllcient to hold the armature against further upward travel. When the ratchet-arm 20 is in this mid-position the notch 88 is at the roller 81 and therefore the spring 95 moves the bar I2 against the ratchet 88, thereby releasing 88 from the notch-wheel 25. At the same time the pin 88 releases the latch 23 from holding the wheel 25, which is therefore free to turn and so it is rotated counter-clockwise until the pin 50 reaches the lower end of the slot II, thereby stopping the wheel 25 at its reset position.

Whenever overload conditions occur, the pull of the solenoid II is enough to lift the armature I4-I5 against gravity and against the tension of the spring 40 until the pin 44 comes against the core I2, as shown in Fig. 2. Now if the overload is suddenly succeeded by no-load conditions, as when the main oil circuit breaker opens, then the armature I4-II is released to drop to the no-load position. In doing this the bar 28 is dropped quickly, and there is not time for the roller 91 to enter the slot 88 before the slot has passed beyond the roller. roller 81 is retarded by the inertia of the wheel 2|, for the roller 81 cannot be moved without partially rotating the heavy wheel 2|.

Since the ratchet 88 is thus not moved by the end of the bar 82, it engages with one of the teeth of the notch-wheel 25 and moves it clockwise one tooth, whereupon the latch 23 engages and holds the wheel. Now if a second overload condition occurs and is followed immediately by the opening of the circuit breaker and no-load conditions, then the ratchet 89 again turns the wheel 25 another tooth. A third overload-tono-load operation will turn the wheel 25 another tooth, making a total of three notches from the reset position. As the third notch motion is made the pin 50 engages with the tail of the latch 52, thereby disengaging 52 from '1 This releases the toggle 55, 58, 58 so that 51 can rotate counter-clockwise about its pivot 54, carrying with it the latch BI and so releasing the projection 04 on switch arm 4. Impelled by the spring contacts 68 and 51, the arm 4 swings outwardly and downwardly thereby opening the main electric circuit between 8 and 5.

As the arm 51 completes its switch-opening motion, the spring 69 engages the extension 10 of the arm 1| and partially rotates the arm 1| around the pivot 12. The member 16 moves the latch 23, and member 11 moves latch 89, thereby releasing both latches from the wheel 25 which immediately turns counter-clockwise to its re- Such motion of the set position, due to the biasing spring 25'. Pins 14 and 15 limit the travel of arm 1I.

With no pressure against the latch 6|, the spring 80 resets the linkage 55, 56, 51 to normal position shown in Fig. 4, and then when the arm 4 is again manually closed it is held by the latch 9| in normal closed circuit position. With the arm 51 in normal position, the spring 18 biases the arm 1| against the stop 15.

After the first or second notching operation, it normal current is established through the main circuit, the armature I4, I5 assumes the midposition, thereby placing the slot 38 adjacent to the roller 31. Therefore, the spring 35 moves the bar 02 against the latch 39 and the pin 36 moves the latch 28. This releases the wheel 25 which immediately resets, impelled by spring 25.

By changing the length of slot 5| the reset position of wheel 25 is readily modified, and so the device may be arranged to open the main circuit after any predetermined number of notching operations, limited by the number of teeth in the wheel 25. And whatever the setting of such adjustment, normal current flowing through the circuit at any time before the completion of the predetermined number of notching operations, will cause the wheel 25 to be reset. After such resetting the notching sequence again begins at zero.

The invention may also be used in operating a three-phase switch. Fig. 6 shows a single unit of such a three-pole switch, in which the base 19 supports the stationary switch insulator 10' the rotative switch insulator 80, and the tubular insulator 8|. The operating rod 80' rotates the insulator 80 thereby moving the switch arm 82 and also the crank 83 and the interconnecting bar 88', by which the two other poles of the switch are operated.

On top of insulator 9| in a housing 84 is a solenoid in series with the line and corresponding to solenoid I2, I3, I4, I5 in Fig. 2. The insulating rod 85 inside the tubular insulator 8| corresponds to bar 29 in Fig. 2.

Attached to the lower end of insulator 9| is a housing 00 within which are members shown in Fig. 8. The rod 85 is pivoted to the arm 01 which moves about the stationary pivot 80; and the spring 09 biases the arm 81 as indicated, thereby partially counterbalancing the weight of rod 85-. The stop pin is similar to stop pin 44 in Fig. 2. The stop 9| limits the downward travel of arm 01, which has the three definite no-load, normalload and overload positions similar to those explained for the Fig. 2 equipment. The arm 92, the roller 98, the spring 94, the latch and the stop 98 correspond to the parts 29, 81, 35, 39, and 4| in Fig. 2. The pivots 91 are stationary and the links 90, 99 movably support the bar I00 with its roller 93 and its biasing spring 94. The link 98 carries a contact block I0| which closes circuit I02 when bar I00 is moved to the right as the roller 98 drops into the slot in bar 92. The contact arm I09 is pivoted at I04, biased clockwise by spring I05 and limited in its travel by stop I06. At normal-load position latch 95 does not engage arm I03; at overload position 95 engages with arm I03, and when dropping suddenly from overload to no-load position, latch 95 pulls arm I03 downward bridging the two spring terminals of circuit I01 and momentaril closing the circuit I01. At the bottom of its full travel, latch 95 encounters stop I08 which moves 95 counterclockwise and so releases arm I03, which then returns against stop I06.

assssse At a suitable location the solenoid I and its armature H0 operate the latch III and so turn the notch wheel H2 one notch against the bias of its spring H3. Stop Ill and pin H limit the counter-clockwise movement of wheel H2 and determine its initial position. After the predetermined number of notching operations, the pin H5 presses downwardly on the spring contact IIB, thereby closing circuit H1, H1 at H8, as shown in Fig. 8. Operating on the same pivotal shaft with wheel H2 is the circular switch H9 which opens its circuit only when the wheel H2 is at its zero position, and keeps its circuit closed at all other positions of wheel H2. Solenoid I20 by means of rod I2I acts to release III from wheel I I2 and also lifts the ratchet I22 about its pivot I23 thereby releasing it from wheel II2.

As shown in Fig. 'I each pole of a three-pole installation includes a unit as shown in Fig. 6, and from each housing 86 two circuits, I02 and I01, extend to the housing 86'. These last may be located at any convenient position, and a suitable battery provides current to operate all the devices. In any one of the switch units, overload followed suddenly by nc-load conditions will momentarily operate the bar I03 to close circuit I01, thereby energizing the coil I05 and notch- 2. An electric switch system comprising an electric switch biased toward open circuit position, holding means to hold the switch closed, a tripping solenoid operable to release the holding means, and electric controls to operate the said solenoid; the said controls comprising solenoid means with an armature movable between. two positions, respectively, under conditions of noload and overload current flow through the switch and operable to assume and to maintain under normal load conditions a definite position intermediate between the said no-load and overload positions, a registering member operable to make a. registration only when the solenoid control means respond to a sudden change from overload to no-load conditions, operable to be ing the wheel I I2 clockwise for one notch. After the predetermined number of such operations successively, the pin H5 acts to close the corresponding circuit III-I II. This in turn energizes solenoid I24, which releases latch I25 so that spring I26 opens all three switch arms 82-42.

However, it normal current occurs in the same line solenoid before the predetermined number of notching actions has occurred, then the parts in housing 88 assume positions shown in Fig. 8

and so close circuit I02 and energize solenoid I20. This lifts rod I2I, thereby releasing wheel H2 as explained, and all membersreset to zero position, with the reset circuit being opened at I I9. If so desired, the motion of the arm I00 may be further delayed by an inertia member, just as the motion of arm 32 is delayed by member One familiar with the art can make manyvariations in difierent features of the device as shown, without departing from thepurposes and principles of this invention. The claims are not to be limited by the particular forms of the invention as shown and described.

I claim:

1. An electric switch system comprising an electric switch biased toward open-circuit position, holding means to hold the switch closed, tripping means operable to release the said holding means, and control means to operate the said tripping means; the said control means comprising solenoid means with an armature movable between two positions, respectively, under conditions of no-load and overload current flow through the switch and operable to assume and to maintain under normal load conditions a definite position intermediate between the said no-load and overload positions, a 1 registering member operable to make a registration only when the solenoid armature moves suddenly from overload to no-load position, operable to be reset to its initial position whenever the solenoid armature stops at its normal-load position, and operable after a predetermined number ofsuccessive registrations to cause operation of the said tripping means.

reset to its initial position by normal-load conditions in the solenoid control means, and operable after a predetermined number of successive registrations to cause the said tripping solenoid to be energized.

3. An electric switch system comprising an electric switch biased toward open circuit position, holding means to hold the switch closed,

tripping means operable to release the holding means, and controls to operate the said tripping means; the said. controls including a notching member and a solenoid that is responsive to current flow in the electric switch and that has an armature movable between no-load and overload positions and operable under conditions of normal load to assume and to maintain a definite position intermediate between the no-load and the overload positions, the armature being operable to notch up the notching member one step for each sudden movement from overload to noload position and to cause operation oi. the said tripping means after a predetermined number of successive notching up operations have occurred and to reset the notching member to its initial position whenever normal load occurs through the said switch.

4. An electric switch system comprising an electric switch biased toward open-circuit position, holding means to hold the switch closed, tripping means operable to release the said holding means, and control means to operate the said tripping means; the said control means comprising a solenoid with an armature operable to take two different positions respectively under overload and no-load conditions of current flow through the switch, and operable under conditions of normal load to assume and to maintain a definite position intermediate between the n'o-load and the overload positions, a registering member operable to make a registration whenever the said armature moves suddenly from overload to no-load position, and operable to be reset to its initial position when the armature remains at the normal-load position.

5. An electric switch system comprising an electric switch biased toward open-circuit position, holding means to hold the switch closed, tripping means operable to release the said holding means, and control means to operate the said tripping means; the said control means comprising a solenoid with an armature operable to take two different positions respectively under overload and no-load conditions of current flow through the switch and operable under conditions of normal load to assume and to maintain a definite position intermediate between the no load and the overload positions, a registering member operable to make a registration whenever the said armature moves suddenly from overload to no-load position, and operable to be reset to its initial position when the armature remains at the normal-load position, together with retarding means to delay the initiation oi the reset operation.

6. An electric switch system comprising an electric switch biased toward open-circuit position, holding means to hold the switch closed, tripping means operable to release the said holding means, and control means to operate the said tripping means; the said control means comprising a solenoid with an armature operable to take two diiferent positions respectively under overload and no-load conditions of current flow through the switch, and operable under condiload to assume and to maintaintions of normal 9. definite position intermediate between the noload and the overload positions, a registering member operable to make a registration whenever the said armature moves suddenly from overload to no-load position, and operable to be reset to its initial position when the armature remains at the normal-load position, together with means operable by the opening 0! the said switch to cause the registering member to be reset.

7. In combination, an electric switch and a control system that includes a solenoid with an armature responsive to the flow of current through the said switch and movable from a noload to an overload position and operable under conditions of normal load to assume and to maintain a definite position intermediate between the no-load and the overload positions, together with means to bias the armature from the overload to the normal-load position'more strongly than from the normal-load to the noload position.

8. In combination, an electric switch and a control system that includes a solenoid with an armature responsive to the flow of current through the said switch and movable from a noload to an overload position and operable under conditions of normal load to assume and to maintain a deflniate position intermediate between the no-load and the overload positions, together with adjustable means to bias the armature from the overload to the normal-load position more strongly than from the normal-load to the noload position. v

GEORGE N. LEMMON.

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