US1466288A - Control system - Google Patents

Description

Aug. 28, 1923. 1,466,288 H. D. JAMES CONTROL SYSTEM Filed May 12 1919 2 Sheets-Sheet 1 ,a H J 3 Hi -/0 5* wnmzsszs: INVENTOR 521M, HenryU. James.

. BY M I A 7 A'TTORbI Y Aug. 28,1 1 923. Y 1,466,288

H. D.IIJAMES CONTROL SYSTEM Filed May 12 1919 2 Sheets-Sheet 2 WITNESSESL ENTOR I Henry D. dames.

. BY M @W Patented Aug. 28, 1923.

(U TED STATES HENRY 1). JAMES, onnnenwoon PARK, PENNSYLVANIAyASSIGNOR 'TO wns'rmc- HOUSE ELECTRIC & MANUFAQTUBING COMPANY, A.CORPORATION OF PENNSYL-z I V ANIA 1 CONTROL SYSTEM.. T

Application filed my 12, 1919. Serial Nb. 296,540;

To all whom it may concern ofEdgewood Park, in the county of Alle- 6 gheny and State of Pennsylvania, have in vented a new and useful Improvement in Control Systems, of which thefollowing is a In ap lication Serial No. 2 19,3414, I have disclose a few reversing systems for a motor that is controlled according to the sys-.

tems of application Serial No. 236,937 In all of these systems, the accelerating resistor is controlled bya relay having a coilthat is responsive to the voltage drop of a port1on 26 or of the whole of the accelerating res stor andby a second coil that becomes energized when the first-mentioned coil becomes deenergized. r I According to'the present invention, the

second-named coil is always energized when.

the motor circuit is closed. Thecontrol system is thereby made mater and the reversing connections are rendered much simpler.

In the accompanying drawings, Figs. 1

vation of a relay of the type constituting the sub'ect-matter of a co-pending application E.;De Camp, Serial No. 241,259, filed June 21, 1918, andassigned to the Westinghouse Electric & Manufacturing 00., which relay is of particular advantage in connection with my invention. Fig. 3 is a schematic view of thee ircuits of Fig. 4:, and Fig. 4 is a diagrammatic View of circuits and apparatiis embodying my invention.

As my invention is of particular valueiin connection with a system employing the De Camp relay above referred to, and illustrated in Figs. 1 and 2, it will conduce to clearness' to describe'thisrelayfirst. I

An insulating panel 29v carries two brackets 30 and 31 supporting the coils 22 and 23 which, when energized by current flowing through them, create magnetic fields Be it known that I,HE1 tnY D. JAMns, a citizen of the United States, and a resident" and2 are, respectively, a side and an end ele-,

for attracting an armature 32 and any ide sired number of additional armatures 33. A compression spring 36 is adjustably mounted upon a non-magnetizable rod 37, slidably mounted in projections 38 and 39, which are rigidly connect'ed'to,or constitute integral parts'of, the bracket 31. A non-magnetizable guide member 72 is provided in the projection 38 for the rod 37. The projection 38 serves also as a pole piece for the armature 32 and the projection 39 as a pole peice for the armatur'es 33. A bar 40 is rigidly connected to the rod 37 and normally engages the armatures 33. The spring 36 thus normally maintains the arinatures 33 in their op'e n p'ositions, with the members 41, which are carried by these armatures, in contact with the .pole plece 39; The members 4:1 are preferably of non-magnetizable materialto pre- The armature 32 is provided with brackets vent freezing.

12, which are Cpi'votally mounted upon the bracket '30, an is normally maintained in contact with one end of the rod 37 by a weak spring 43. A magnetizable member'71 1s mounted upon theprojection 38 for distrib uting the flux that is'adapted to energize the armature 32, thus'renderin'g the armature 32 more sensitive to current changes. The bracket 30 supports a non-magnetizable UTshaped member 44' between the arms of which are pivotally'mounted the armatures 33, which carry, respectively, the movable contact members45, 46 and 47 of relays 25, 26 and" 27 The corresponding'stationar con tact members 48, 19and 50 are the insulating panel 29.

Springs 51 are attached to longitudinally adjustable members 52 and'to the other ends of the members 41. The pole piece 39 is provided with longiudinally adjustable members 53 to regulate air gaps 70 between these members and. the corresponding ar'matures. By means of this adjustment, or by means of the members 52, which control the tension of the springs 51, the action of the magnetic fiux produced by thecoils 22 and 23 may be so regulated that the armatures .33 will be operated inpropersequence. v

The operation may be briefly described as follows: upon current flowing through the coil 22, amagneticfield is createdwhich causes the armature 32 to be attracted tomounte upon ward the pole piece 38. "The force of the spring 36 is thereupon overcome, and the bar 40 is moved out of engagement with the armatures 33, the stop members ll of which are, nevertheless, maintained in engagement with the pole piece 39 until the flux of the magnetic field becomes successively suiticiently low to permit the springs 51 to suecessively actuate the movable contact members 4:5, 46 and 47, thereby to close the relays 25, 26 and 27. In the event that the magnetic field becomes too weak to hold the armature 32 in its elevated position, the spring 36,'becoming released, will separate the movable from the stationary contact members.

Turning now to Fig. i, a motor, having an armature 1, a shunt field-magnet winding 2 and a series lield-magnet winding 84:, is connected between line conductors 3- and 4 by a main kni't'e switch '76. An accelerating resistor 6 is provided in series with the armature l. The direction 01 rotation of the motor is controlled by pairs of reversing eontactors 58 and 61 and 59 and 60 that are respectively controlled by actuating coils 62 and 63 and are provided with mechanically connected switches 66 and 67 that are open when the reversing switches are closed and closed when the reversing switches are open. The circuit of the motor is controlled also by a line contactor 5 having an actuating coil 8.

A plurality of cont-actors l0 and 11 (only two are illustrated) are adapted to effect the short-circniting of successive sections 13 and 14 (but two are shown, for purposes of illustration) upon being actuated to closed position by coils l9 and 20, the circuits of which are respectively controlled by the relays 25 and 26. In order to simplify the drawings, I have shown but two relays in the system ot Fig. l. The coil 22, which controls the relays 25 and 26, is connected in circuit with a resistor 86 across the resistor 6 at the junction points 79 and 80 and the coil 23 is connected to the line conductors 3 and l in circuit with the resistor 24, through a master switch 7 and a knife switch 77, which are adapted to control the control circuits.

A dynamic-braking circuit for the motor is adapted to be established through a dynamic-braking resistor 74 upon the closing or the switches (36 and (37, which switches are adapted to be maintained closed. so long as the counter-electroinotive force of the motor exceeds a predetermined value, by coils 78 and Si. A no-voltage relay 73 and an overload relay 75 are provided, the coil. of the no-voltage relay being adapted to be energized through the master switch 7 which controls also the circuits of the coils S, 23, 62 and 63, as will appear hereinafter.

Assuming that the knife switch 77 is closed and that the master switch 7 has been actuated to its first position at, either to the right or to the left, a circuit is established from the line (,OIltlHCllOI' 3, through the knife switch "4'7, to a stationary contact member 9* of the controller 7 and from there, through the controller 7, tea stationary contact member 9 and thence, through the actuating coil oil? the ire-voltage relay 73, the overload relay T5 and the knife switch 77, to the line conductor l. The no-voltage relay '73 becomes thereupon closed by its actuating coil, and a holding circuit lor the coil is established row the line conductor 3 through the knife switch '77, the no-voltage relay 73 and its actuating coil, the overload relay 75 and the knife switch '77, to the line conductor it. The circuit through the con tact member 9 is broken when the master switch 7 is moved from the position a but the no-voltage relay 73 will be maintained closed by the above-traced holding circuit so long as the ctmductors 3 and at are sup plied with voltage or until the overload relay 75 becomes opened by overload conditions. 2

Assuming that the master switch 7 is actuated to its second posit ion Z), let us say to the lett, a circuit becomes established from the line conductor 3, through the knife switch. 77, the no-voltage relay 73, the stationar contact members 9 and ltl-which are bridged by the master controller T, in the position i), the coils 63 and'S and the knife switch 77 to the line conductor 4. cllCLIlt also established tor the coil .1) in series with the coil (33 and in parallel to the coil the circuit extending From the contact member In, which is connected to the line conductor 3, through the coil (33, the resistor 24:, the coil 2? and the lini'teswitch 77, to the line conductor at. The coil-(5 is thus energized to effect the closing ol the reversing contactors 55) and (30 and the opening of the switch 67. The line contactor 5 closed by its coil 8, and the armature 232 (Fig. I) is actuated into engagement with the mag netizable member Tl by the coil 2?) to cllect the release of the arrnatures 32-3 from their engagement with the bar -10, in opposition to the force of the spring 36. Assuming that the knife switch T6 is also closed. a circuit may now be traced from the line conductor 1% through he l-rnite switch 76, one or the coils ot the overload relay 7:), the reversing contactor 59, the armature l, the reversing contactor (50, the series field-magnet winding 84, the junction point 80, the resistorb. the junction point 79, the line (OllitU-l'Ol 5, the other coil of the overload relay 75 and the knife switch 76'. to the line conductor 4', The circuit or the shunt field-magnet winding 2 becomes immediately established upon the closing oi" the knife switch '76 by a circuit extending from line conductor 3, through the firstnamed coil of the overload relay 75, the

shunt field-magnetvwindingfl, the other coil switch 76, to the line conductor 4.

The motor circuit is thus established for operation of the motor in one direction. The coil 22, which is subjected to the voltage drop across the junction points'79 and '80 of the resistor 6, is energized to aid the coil 23 in maintaining the armature 32 in its of the overload relay and the knife actuated position and to maintain the arma t-ures 33 in such positions that the members 411 are in engagement with the pole piece 39, so that the relays 25 and 26 are. maintained open. As the moior acceleratcs and the current traversing its circuit decreases, in con sequences, the voltage-drop of the resistor 6 becomes decreased so that the spring 51, which is attached to the armature of the relay 25, will effect the closing oi this armature in opposition to the forces of the mag-' netic fields of the coils 22and 23, thereby effecting the closing of the relay Assuming now that the master switch 7 has been actuated to its third position 0, a circuit becomes established from the contact member 9, which is connected to the line conductor 3, by the iio-voltage relay 73, through the master switch 7, the contact member 18, the coil 19, the contact members 18 and 15 of the relay 25, the junction point 79, the line contactor. 5, one of the coils of the overload relay 75 and the knife switch 76, to the line conductor The contactor 10 becomes thereupon closed byits actuat-,

ing coil 19 to effect the short-circuiting of the resistor portion 13.

As the motor continues to accelerate, the voltage drop across the remaining portion of the resistor 6 will become further decreased until, ultimately, the spring 51, which is connected to the armature 33 of the relay 26, will effect the closing of this second relay in opposition to the force of the magnetic .fields of the coils 22 and 23. A circuit then becomes established through the coil 20 and the relay 26, in parallel to the coil 19 and the relay 25, whereupon the contactor 11 becomes closed byits actuating coil to effect the short-circuiting of the remaining portion 14 of the resistor 6. The motor will now operate at itsnormal speed.

Upon the short-circuiting of the entire resistor 6,,the coil 22 becomes, of course, de-

energi-zed, but the coil 23, it properly designed, will 11121111133111'0116 armature 32 in engagement with the magnetizable member 71 to maintain the armatures 33 released from the control of the bar 40 (Fig. 1) but will not effect the reclosing of the armatures' in opposition to the forces of the springs 51. The motor, therefore, will continue to operate at normal speed.

It the master switch 7 be returned to the position b, the circuits of the coils 19'and 20 will become reopened and the resistor 6 -will becomc reinserted intothe armature circuit. If the master switch 7 be. returned to-the position a, or ii the iio voltage relay 73'becomes opened by the low voltage coiiditions,-or if the overload relay 751301011188 N a conductor 82, through theswi'tch 67, the

dynamic-braking resistor 74, the switch 66 and by a conductor 83, to the other brush of the armature 1. During the dynamic-braking operation, the switches 66 and 67 will be maintained closed not only by gravity but also by the coils 78 and 81, respectively, which are maintained energized. in accord ance with the voltage dropacross the dynamic-braking resistor 74. lVheii the volt-' age across the resistor 74: fallsto a sulficiently low value, the coils 78 and Y81 will not be very strongl energized and it will be possible to estabi'shed the motor circuit for operation in the same or in i'liereverse direction upon energization of the coils 63 and 62, respectively, in accordance with the position of the master switch 7.

To operate the motor in the reverse direction, the master switch 7 will be actuated to the right; the operation will be substantially the same, the only difference being that, instead ofthe coil 63 being energized through the contact member 16, the coil 62 will-be energized through the contact member 17. The reversing contactors 58 and 61 will become closed to establish the motor circuits for operation in the "reverse direction. The accelerating and the dynamicbraking operations .are substantially the same as those above described.

The novelty of the present invention, specifically stated, resides, therefore, in so connecting the coil 23 that it will be maintained energized during the accelerating operation, so that the necessity for inserting a coil into circuit to take the place of the coil .22 upon the short-circuiting of the resistor 6, as is done in my above-mentioned co-pefinding ZIPPllCZLtlOllS, is avoided.

'I claim as my invention: I

1. The combination with an electric circuit, of a switch for controlling said cir-' cuit, and a relay for controlling said switch,

said switch comprising actuating means therefor and said "relay. having means comprising a pair of assisting coils for controlling the effectiveness of .said actuating means, one of which is controlled in accordance-with the electrical conditions of a p0rand a source of energy therefor, of means comprising a switch for controlling said motor, and a relay for controlling said switch, said. switch com'prisii'ig actuating means therefor and said rela having pair oi assisting controlling coils one oil which is controlled in accordai'ice with the (l potential across a. portion of saitl circt it and the other of whicn is conneetefl t source and energized in accordance with the voltage thereotwhenever the circuit of said. motor is closed.

3. The combination with an electric motor, a resistor in series therewith, and a source 0:! ei'iergy for said motor, ol' n1 :ans comprising a switch tor controlling said resistor. said switch comprising means "for actuating ii to its closed position and hat ing, also, a pair o'l' assist ng coils one. oi which is controlled in accordance with the drop in potential across said resistor. and the other oi" which is connected to source andis energized in accordance with the voltage thereof.

4;. The combination with an electric inotor having a resistor associated therewith and a source of energy for said motor, of means comprising a switch for controlling nltlli rop in said said resistor, said. switch comprisil'ig means lior hiasing; it to its closed position and liming; a, pair of assisting conirollii'ig coils rich connected across said rea'l-sch, when eno ized below a med degree, 'pern' rts said switch 211(l the other oi which is connected to said source energization thereliy anl must he energized prior o the closing of said switch.

5. The combii'iation with an electric motor and a resistor in ircuit therewith, of means 'lor controlling said resistor comprising a switch, means tending to close said switch, and means l'or i-(mtrollii'ig said closlll ijj means coin 'irising a coil energized in acctndance with line voltage while the motor tircuit is closed and a coil for assisting the first-named coil and that is energized in accordance with the drop in potential across said resistor, which, when energized below a predctermined. degree, permits said switch to close.

In testimony whereof, I have hereunto subscribed my name this 30th day of April 1919.

HIGNB Y D. JAMES.

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