US1569374A - Control apparatus - Google Patents

Description

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Falls/.fion

INVENTOR ,Howard #Jo/Ins fon.

AT'TORNEY Patented Jan. 12, 1926.

UNITED STATES PATENT OFFICE,

HOVAED EOHNSION, O17 EGETOOD PARK. ENNSYLVA'NA, ASSIGNOR TO WEST- lliGr-IGSE ELECTRIC @t SYLVANIA.

To all liti/wm 'it may concern.'

Be it lrnown that l, HOWARD H. sloriNs'roN., a citizen of the United Stat-es, and a resident oi. Edgewood Park, in the county ot .tillegheny and State ot Pennsylvania, have invented a new and useful Improvement in Control Apparatus, ot which the :tollowing is a speciiication, this application being a ldivision ot my copendingl application Serial No. 299,183, tiled May 23, 1919, and assignedV to an overload, current.

Another object ot my invention is to provide a combined relay device ot the aboveindicated character having a plurality ia actuating coils so connected to the loadcircuit to be controlled as to eltect similar actuat-ions of the device during the occurrence olE a predetermined load-circuit current or oi a substantial doubling thereot; or, in other words, l provide a single relay device tor a'liiording the same limit-switch operation during the series-parallel connections oiC a plurality ot electric motors, tor example, and also the same degree ot overload protection dining both series and parallel operation ot the motors.

@ther speci'lic objects oi? mv invention will evident trom the toll-ownV detailed description, taken in conjunction with the accompanying drawing, wherein Figure 1 is a view in elevation' ot a combined relay device constructed in accordance with the present invention; Fig. 2 is a diagrammatic view ot a series-parallel system oi control Aembodying the relay d vice that is sh wn in Fi l; and Fig. 23 is a chart resenting various thisr values during dirieient ope"- ating conditions ot the relay device.

Referring te rig'. 1, the re sin vn comprises a series or current coil 1; a shunt i918 Serial No. .299,l33.

CONTPJOL AEARATUS.

Divided and this application filed September Serial No. 585,872.

or voltage coil 2 alined therewith; concentric-ally related stationary and movable core members 3 and 4, respectively; a plurality oi" movable contact members or discs 5 and (i, respectively corresponding to the limitswitch and to the overload-trip functions ot the device, both ot the contact discs being loosely mounted upon a centrally-located rod or core member 'i' that extends through both the movable and the stationary core members 8 and l, respectively; and a movable armature device 8 for a purpose to be set forth.

The series coil 1 comprises a plurality ot eonvolutions of strap conductor ot suitable current-carrying capacity, while the shunt coil Q may he formed ot' relatively small cross-section wire, since only a relatively low current passes therethrough.

'lhe stationary core member 3 is located substantially within the series coil 1, while the movable` core member or plunger et is substantially surrounded by the shunt coil 2 a suitable length of air-gap being leit between the two core members, in accordance with a familiar practice. Also, a suitable spring ta, located in the air-gap, serves to bias the plunger l to the illustrated upper position.

The contact disc 5 is resiliently associated with the concentrically-related rod 7 and movable core by means of a coil or compression spring 12, one end ot which engages the upper tace ot the core, the spring acting to torce the disc 5 upwardly towards the illustrated position, and also towards a position ot electrical contact with a set o't stationary terminals 14e and 15, which are connected in the customary circuit that is controlled by a limit switch or current relay in automatic control systems for railway motors, and the like. A centering member 12a moves with the plunger' to limit the upward travel thereof. y

The contact disc 6, corresponding to the overload-trip function of the relay de vice, is likewise resiliently associated with the rod 7 through the agency of a helical spring 16, the upper end ot' which bears against a pin 17 in the rod 7 to bias the contact disk downwardly towards a position ot engagement with another pin 18 and also towi 1s a position of electrical contact with a plurality ot stationary Contact terminals 19 and 20, which are connected in circuit in accordance with the familiar practice relative to overload-trip devices.

As previously stated, the rod 7 extends through both the stationary and the movable core in .nb-ers 3 and 4 respectively, being jour-nailed at its upper end in a suitable strap or bracket 21, the lower end of the rod projecting slightly below the stationary core member 3 and resting upon an oscillatable arn'iature or magnetizable member 22, one end of which is pivotally mounted upon a "r-.ole pin 23. The entire armature device t3, including the arn'iature proper 22 and a latch or detent- 24, is preferably of the well-lmov-:n form that is customarily associated with overload-trip relay devices. See, for example, Patent No. 1,312,757, `granted August 12, 1919. lVithout complete illustration, it will be understood that the latch 24 normally holds the armature 22 in the illustrated position and is itself biased downwardly to prevent the return of the armature 22 to the illustrated position after it has been attracted upwardly by the core members to its overload position. Preferably, the familiar electrically-controlled resetting device is also associated with the latch `24 to return the latch and the armature to the illustrated position whenever the motorman throws a controlling switch. Since the resetting feature is well-known in the art, and, moreover, is not essential to the operation of my present invention, I have not deemed it necessary to completely illustrate this device.

rlhe mechanical operation of my combined relay device may be set forth as follows: Assuming first that the series coil 1 alone energized, the movable core member 4 is attracted downwardly, to allow the contact disc to drop from its position of engagement with the stationary contact terminals 14 and 15, whenever a predetermined value of current, corresponding to the desired normal il'iaximum operating value in the load circuit, traverses the series coil 1. As soon as the current oecreases to a certain value, the movable core or plunger 4 is returned by the spring 4a to its illustrated upper position to resiliently actuate the contact disc 5 to the position of engagement with the contact terminals 14 and 15. In this way, the familiar intermittent energization of the desired au i .ity governing circuits in an automatc system of control, correspondingr to the well-known limit-switch or currentrelaU action, is provided by the illustrated relay fico.

If the current in the series coil 1 attains an undesirably high or overload value, the armature 22 is attracted upwardly to a position of direct engagement with the lowerl f:-.ce of tno stationary core member 3 to carry the rod 7 upwardly to a sufficient extent to lift the contact disc 6 out of engagement with the terminals 19 and 20. In this way, the customary governing circuit corresponding to overload-trip protection is opened at any desired main-circuit current value, dependent upon the adjustment of the armature device 8, as will be understood by those skilled in the art. During the overload operation just described, the limitswitch disc 5 is retained spaced from the contact terminals 14 and 15 by reason of the previously described action of the core 4.

Consequently, the limit-switch and overload-trip functions of the relay device are accomplished entirely independently of cach other, and, moreover, employ different magnetiza-ble members, viz, the movable core 4 and the armature 22, for effecting the desired results.

Referring to Fig. 2, the system shown is of a familiar type for controlling a plurality railway motors and comprises, essentially, l,able supply-circuit conductors such as li alley and Ground; a plurality of dynamoelectric machines, respectively having commutator-type-armatures A1 and A2 and series iieid windings F1 and F2; an accelerating resistor B0; and a plurality of switches: LS for governing the connection of the motors to the supply circuit, R1, R2 and R3 for iort-circuitinel different sections of thc acc;.erating res 30, S corresponding` to series connection of the motors and P and G corresponding to parallel relation of the motors.

My combined relay device is illustrated diagrammatieally in Fig. 2, the series actuating coil 1 being continuously connected in series relation with the motor circuit to receive the full current thereof, while the shunt coil 2 is connected in a circuit that established from the Trolley through conouctor n s-, interlock P-in of the parallel-connecting switch l?, conductor 32, actuating coil 2, adjustable resistor' 353, and thence to Ground. in other words the series coil l registers the current flowing through the motor circuit, whereas the shunt coil 2 measures the voltage across the motor circuit.

lA asinuch as an auxiliary governing system for the v switches shown in Fig. 2 may be readily devised by those skilled in the art, in accordance with well-known operating principles, I have not deemed it necessary to ill ustrute or describe such an auxil' svstem. hiloreover. since the ordinary Vch and overload-trip functions are i and the connections of the sepdeviccs that. are normally er "here two purposes are also fac itl-ered it necessary to il such coiu'icctions of the lnoviously to the cusilly,

stated, correspond in every way tomary limit-switch and overload-trip operations, respectively.

Assuming that it is desired to effect series operation ot the illustrated motors, the switches LS and S are closed to establish a circuit 'trom the Trolley through the seriesactuating coil l of my relay device, line switch LS, the entire accelerating resistor 8l), armature Al, held winding Fl, switch S, ai'-im\tr1re A2, and field winding F2 to Ground. rllhus, the series actuating coil l receives the full current traversing the mo tors, whereas the shunt actuating coil 2 is dcenergized by reason ot' the open condition ot the switch P and, therefore, ot the circuit for the actuating coil.

lt will be understood that the resistor short-circuiting switches Rl, R2 and R?) may be successively closed, in accordance with the operation of the actuating coil l and the contact disc of my relay device, as previously set forth, to gradually short-circuit the accelerating resistor 30 and accelerate the motors to full series relation.

rihe familiar shunting transition ot' the motors, involving the closure or" switch l), the openingot switch S and the closure ot switch Gr, may then be eltected to thereby connect the motors in parallel relation, as will be evidentwithout a detailed tracing of the circuits. Consequently, the combined current that traverses the two motors, equalling substantiallyv twice the amount flowing through the motor circuit during series operation, also traverses the series actuating coil l oi my relay device. For this reason, the limit-switch set-ting ot the relay device would be substantially doubled over that employed during series acceleration and desir-ed duringh parallel operation also, were ilv not Yfor the additional provision that I make. However, by utilizing the shunt coil during such paraliel operation and connecting it ditlerentially with respect to the series-actuating coil l, the same limit setting,

nd lilrewise the saine degree ot overload protection, is obtained during` both series and `parallel connection of the motors, irrespective of the substantially doubling of current in the series-actuating coil l.

The energization of the shunt coil 2 is automatically e'tfected upon the closure ot' the parallel-connecting switch P by reason ot the formation of the previously traced circuit through the coil 2 and the interlock P-in. By mechanically adjusting the armature 22 of the relay device in the usual manner, before the car is put into service, to provide the desired degree of overload protection, and by then manipulating the resistor 33 to a corresponding condition, the actuating coils l and 2 ot the relay device, by reason ot their differential. action, will provide the same degree ot. magnetic attraction or the same amount of effective flux during both the series and the parallel operation otthe motors.

This tact is graphically shown in Fig. 3, wherein the vector QS, corresponds to the average 'flux emitted by the series-actuating coil l during series operation ot the motors, or; in other words, the vector o, is a measure oit the average magnetic attraction upon the movable core 4 or" the relay device. A substantially equal value of hun' is created by the series coil l during the transitional period, while an equal and opposite amount ot. tiux, represented by the vector o, is pro duced by the shunt coil 2 during the transition ot the motors trom series to parallel relation, betore the parallel connection is actually complet-ed.

ylChe normal or average flux conditions in the relay device during such parallel operation are represented by the correspondingly designated vectors in Fig. 3, o, representing the substantially doubled flux created .in the series coil l by reason of the parallel connection ot the motors, while o2 indicates the opposing or ditierential lluX that is set up by the shunt coil 2. Consequently, the etiective flux that acts upon the movable core member a is substantially equal to the tluX l, which represents the total tiux created by the relay deviceI during series operation ot the motors.

The next succeeding set of vectors in Fig. 3 shows a vector o4, greater than the sum of the vectors o, and o3, to represent the increased total flux that is produced in t-he relay device whenever the limit-switch portion thereof functions to elifect the Operation ot a resistor' short-circuiting switch such as Rl, which, ot course, causes a temporary increase ot current in the. motor circuit. rlhe vector 525 therefore, corresponds to the value of current necessary to effect the prcviouslydescribed linut-switch action ot my relay device.

The next set oi vectors in Fig. il includes a vector 56 longer than the vector and corresponding to the amount oi current that is required to traverse the series actuating coil l to cause the armature 22 to assume its upper position and thus liilit the contact disc 6, whereby the desired overload protection ot the motors is provided.

The last vector e, corresponds to the etective flux produced by the relay device under overload conditions. As ,indicated by the accompanying legends, the vector o6 is equal to the sum or the vectors, o, and o5, or to the difference ot the vectors o, and o3, plus the vector ep Since the vectorial sum ot e, and o, represents the eiective magnetic attraction exerted by the relay device during` parallel operation of the motors, while the vectorial diti'erence of and om plus the vector y represents that attraction during series connection of the motors, it tollit) lows that substantially the same degree of overload protection is automatically furnished by my relay device during both series and parallel operation. By analogy, it also follows that the same average current is maintained by the limit-switch action of my relay device under both conditions ot motor operation.

I do not wish to be restricted to the speciiic structural details or arrangement of parts herein set forth, as various modiiication thereof may be effected without departing trom the spirit and scope of my inveni tion. l desire, therefore, that only such limitations shall be imposed as are indicated in 'the appended claims.

l claim as my invention:

l. ln a switch, in combination, a plurality of contact members for controlling electric circuits, a movable contact carrier, said Contact members being movably mounted on the carrier, electromagnetic means adapted to effect the movement of a contact member independently of the carrier, and means operated by said electromagnetic means disposed to actuate the carrier.

L. ln a switch, in combination, a plurality of contact members for controlling electric circuits, a movable contact carrier, said contact members being movably mounted on the carrier, electromagnetic means adapted to ei'i'ect the movement of a contact member independently of the carrier, means operated by said electromagnetic means disposed to actuate the carrier, and resilient means cooperative to urge the contact members to predetermined positions relative to the carrier. u

3. In a switching device, the combination with a movable core member, oip4 an actuating coil therefor,l a rod extending through said core member, and a plurality of contact members mounted upon said rod and resinectively1 actuable by the core member and the rod.

d. In a switching device, the combination with a movable core member, of an actuating coil therefor, a rod extending through said core member, a plurality of sets of stationary contact terminals, and a plurality orp contact members mounted upon said rod and respectively actuable upwardly by the core and downwardly by the rod to engage 'the respective sets of contact terminals.

5. ln a switching device, the combination with movable core member, of an actuating coil therefor, a rod extending through said core member, a plurality of sets ol' stationary contact terminals, and a plurality of contact members resiliently mounted upon said rod and yieldingly actuable upwardly by the core to engage one set of contact terminals and yieldingly actuable dow" wardly by the rod to engage another set, respectively.

(i. in a switching device, the combination with cia-operating stationary and n'iovable core members, ot a plurality of actuating coils substantially enclosing` the respective core mei'iibers, a red extending through the core members, a plurality oit' sets ot stationary contact terminals a plurality olf contact discs resiliently nted upon said rod one oi whicli is yieldinnly actuable upwardly by the core to engage ono set of contact terminals, and an armature attraclable by said core cn'ibers to actuatc said rod and eti-ect disengagement of a second. contact disc trom a second ot contact terminals.

i'. in a switch, in combination, a movable contact-carrying member, a plurality ol conrs mo Yably disposed on said tact membri.. member, a coie mcn'il'ae operable to eli'ect a ovement of a contact member independently of the contact-carying men'ibcr, an actuating coil for the core member, and means actuated by the coil disposed to operate the contact-carrying member.

8. ln a switch, in con'ibination, a movable contact-carrying member, a plurality et contact members movably disposed on said member, a core member operable to effect a movement of a contact member independently oi the contact-carrying member, an actuating coilfor the core member, and means actuated by the coil disposed to operate the contact-carrying member, said core and contact-carrying member being disposed to move the contact members in opposite directions.

9. ln a switching` device, the combination with a movable core member, of an actuating coil therefor, a rod extending through said core member, a plurality oil stationary Contact terminals, and a plurality o'E contact members, respectively actuable in opposite directions by said core member and said rod to engage the respective stationary Contact, terminals.

lO. ln a switch, in combinal ion, a movable contact-carrving nieinber, a plurality or" contactmembc movably disposed on said member, a core operable to effect the actuation oiC a contact member independently oit the contact-carrying member, resilient means (5o-operative with the core to urge the contact member to a predetermined position relative to the carrying member, an actuating coil for the core, and means energized by the coil to operate said carrying member.

In testimony whereof, l have hereunto subscribed my name this th day of' August, 1922.

HOUR/LRD H. JOHNSTON.

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