US2318116A - Regulating system - Google Patents

Description

' May 4," 1943. L. G. 'rusas 2,318,116

REGULATING SYSTEM Filed June 13, 1942 17 WITNESSES:

WW I aw m? INVENTOR I Lester G. Ebbst sible value of voltage Patented May 4, 19 43 2,318,116 REGULATING SYSTEM Lester G. Tubbs, Wilkinsburg, Pa.,

assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa.,

Pennsylvania a corporation of Application June 13, 1942, Serial No. 446,855

Claims.

This invention relates to regulator control, circuits and in particular to improvements in time delay control circuits for electrical regulators.

In voltage regulators, the control apparatus is usually arranged to start movement of the regulator in a very short time after the voltage which is to be controlled has exceeded a prede termined variation from normal voltage. In most cases this method of operation is desirable in order to have the voltage brought back to normal as quickly as possible. There are certain cases, however, in which the voltage which is to be controlled varies quite rapidly, stay at an abnormal value for-only a short time, and then return to normal or even go beyond the permisin the other direction. In such cases, by the time the movement of the regulator has taken place, the voltage may have changed to'some other value, causing the operation of the regulator just completed to be of no value or even detrimental.

Heretofore attempts'have been made to provide a time delay responsive action in the operation of the regulator, but the apparatus employed usually included parts which operated mechanically and were subject to wear, thereby requiring maintenance, or the apparatus necessitated an operation of the time delay device to interrupt the operation of the regulator.

It is an object of this invention to provide a new and improved regulator control system.

' rent employed is an exclter generator which Another object of this invention is to provide a regulating system having time delay characteristics but which operates independently of such time delay for interrupting the operation of the regulator.

A more specific object of this invention is to provide a regulating system having a thermal time delay which is unaflected by changes in ambient temperature and to so control the regulator as to interrupt its operation independently of the operation of such time delay.

Other objects of this invention will become apparent from the following description when taken in conjunction with the accompanying drawing in which:

Figure 1 is a diagrammatic illustration of the apparatus and system provided in accordance with this invention.

Fig. 2 is a view in elevation with a part broken away of apreferred time delay apparatus employed in the circuit of Fig. 1;

Fig. 3 is an elevation view, partly in section, taken along the line III-III of Fig. 2;

Fig. 4 is an enlarged fragmentary view of a part of the apparatus of Figs. 2 along th line IVIV of Fig. 3, and

Fig. 5 is an enlarged fragmentary view of another part of the apparatus of Figs. 2 and 3 takenalong the line V-V of Fig. 3.

Referring to the drawing and in particular to Fig. 1 thereof, there is illustrated a regulating system for maintaining the voltage of the generator l0 substantially constant. The generator 10 is provided with an armature winding 12 and a field winding l4. As illustrated, the armature winding 12 is connected across a line comprising conductors l6 and I8 and the field winding 14 is and 3 taken connected to any suitable source of direct current. In this instance the source of direct ourmay be driven in any suitable manner by a motor or other prime mover (not shown). The exciter 20 is connected by conductors 22 and 24 to the 'field winding l4, a motor operated field rheostat 26 also being'connected in the exciter circuit with the field winding.

As illustrated, a pilot motor 28 is provided for operating the rheostat 26 and is connected thereto by means of the worm and gear drive 30. The rheostat 26 is of any well known construction and is provided with an adjustable contact arm 32 which electrically engages the resistor element. The rheostat motor 28 is provided with an armature winding 34 and field windings 36 and 38. An auxiliary control device comprising the relays 40 and 42 are disposed to be connected in circuit relation with the field windings 36 and 38, respectively, to control the operation of the motor 28 from a battery 44, as will be explained more fully hereinafter.

Since it is desired to control the operation of the relays 40 and 42 in accordance with changes in the voltage across the line conductors i6 and I 8, a primary control device 48 is provided having its operating winding 48 connected by conductors 50 and 62 to the line conductors l6 and I8, respectively, whereby it is energized in accordance with the voltage on the generator ill.

The energization of the operating winding 48 of the primary control device 46 changes with the voltage on the generator Ill and operates a contact carrying arm 54 about its pivot 56 against the bias of a spring member 58 to actuate one or the other of contact members 60 and 62 into engagement with fixed contact members 64 and 66, respectively, depending upon whether the change in the voltage is an increase or decrease. Normally, the contact carrying arm 54 is in the neutral position illustrated when a predetermined I and 14 disposed spaced normal voltage is on the generator. The contact carrying'arm 54 is of conductive material and is connected to conductor 50 by conductor 68.

As illustrated, a thermal time delay device is disposed to be connected in circuit between the primary control device 46 and the control relays 40 and 42 of the rheostat motor 28. The thermal time delay device 10, shown diagrammatically in Fig. l, is preferably of the type illustrated in Figs. 2 and 3. As illustrated, the device 10 comprises a pair of stationary contact members 12 apart but facing each other, and a pair of movable contact members 16 and 18 disposed for cooperating therewith for closing a predetermined circuit.

Each of the stationary contact members 12 and 14 is mounted on a resilient leaf member 80 which is secured to a support 82 mounted on the.

panel 84 by means of the conducting screw 86 and the connecting nut 88. As illustrated, the support 82 also carries an insulating member 90 on the side opposite the leaf member 80 for effectively insulating an adjusting member 92 therefrom. The adjuster 92 is an elongated screw member positioned through a suitable opening (not shown) in the housing of the time delay device, and is disposed to be turned to bear against the end of the insulated support member 82 to position the fixed contact member 12 or 14, as the case may be, relative to its cooperating movable contact member.

Each of the movable contact members 16 on 18 is carried on an elongated substantially U-shaped bimetallic element 84, one leg 96 of which is longer than the other leg 98, as more clearly shown in Fig. 3. The bimetallic elements 94 are so mounted that they tend to bend away from one another when heated. Each of the bimetallic elements 94 is mounted on an L-shaped supporting member I00, the ends of the legs of the thermal element being secured thereto by any suitable means.

As illustrated in Fig. 5, the longer leg 96 of the element 94 is secured to the support I00 by means of the rivet I02 which extends through an enlarged opening I04 in the leg, layers of insulation I06 and I08 being provided for effectively insulating the leg from the support member I00 and the rivet I 02. The lower end of the leg 96 terminates in a curved end which forms a terminal clip 91 for a lead.

The mounting for the shorter leg 98 of the element 94 is illustrated in Fig. 4. As illustrated. the leg 98 is in electrical contact with one leg of the L-shaped support I00, the rivets IIO being very close fitting and providing an electrical path therebetween. The base of the support I00 is secured to the panel 84 by means of the screw member I I2 and the connecting nut I I4, terminal clips H6 and H8 being provided for making electrical connections thereto.

As illustrated in Fig. 2, the movable contact members 16 and 18 are held in spaced relation to each other by means of an insulating spacer member I20 which fits over projecting lugs I22 provided on the upper end of each of the elements 94. This spacer member I20 ensures correct operation of the movable contact members and prevents movement of either of the movable contact members in response to a change in ambient temperature.

Again referring to Fig. 3, the thermal delay device 10 is provided with a transformer I24 associated with the movable contact member 16 and a transformer I26 associated with the movable contact member 18. These transformers may be so assembled as illustrated as to operate on the same core member I28, the transformers being built in and carried by the housing of the thermal delay device.

Each of the transformers I24 and I26 is pro I32. Likewise, the primary winding I30 of the transformer I24 is connected by leads I38 and 140m a terminal clip I42 secured on the panel 84 by the screw I39 and connecting nut I4I and the terminal clip I I6 carried by the support member I00, respectively, the terminal clip II6-being in electrical contact with the shorter leg 98 of the element 94. For convenience, the leads of only one of the transformers, namely I24, are illustrated in Figs. 2 and 3, although it will be obvious that similar leads and connections will be provided for the transformer I26 which is associated with the fixed contact member 14 and movable contact member 18.

Referring to Fig. l, transformer I26 of the thermal delay device 10 is illustrated with its primary winding I30 connected to the fixed contact member 64 of the primary control device 46 by conductor I44 and to the conductor 52 by conductor I46. Likewise, one side of the secondary winding I32 of transformer I26 and one le of the bimetal element is connected by lead I40 and conductor I44 to the fixed contact member 64, the other side of the secondary I32 being connected to the other leg of the thermal element carrying the contact member 18.

In a similar manner, the primary winding I30 of transformer I24 is connected by conductor I48 to the fixed contact member 66 of primary control device 46 and to the conductor 52 by conductor I50. Likewise, one side of the secondary winding I32 01 the transformer -I24 and one leg of the bimetal element 94 is connected by lead I40 and conductor I48 to the fixed contact member 66, the other end of the secondary winding I32 being connected directly to the other leg of the bimetal member 94 which carries the movable contact member 16.

The fixed contact member 14 of the thermal delay device 10 is illustrated as being connected by conductor I52 to the operatin winding of the relay 40, and thence by conductor I54 to the conductor 52. Similarly, the fixed contact member 12 is connected by conductor I 56 to the operating winding of relay 42 and thence through conductor I54 to the conductor 52.

In operation, assume that the voltage on 'the generator I2 is at a normal voltage and the apparatus illustrated diagrammatically is substantially as shown. If, for any reason the voltage on the generator I2 increases, then the energization of the operating winding 48 of the primary control device 46 is increased to effect a movement of the contact carrying arm 54 in a clockwise direction about its pivot 56 against the bias of the spring 58 to actuate the movable contact member 60 into a circuit closing position with the fixed contact member 64. Such movement of the movable lower contact member 60 establishes a circuit which extends from line conductor I6 through conductor 68, conductor 68, the contact carrying arm 64,.engaged contact members 68 and 64, conductor I44, the primary winding I88 01 transformer I26, and conductors I46 and 52 to the line conductor I8. The energization of the primary winding I38 of transformer I26 induces a flow of current through the secondary winding I32 and the bimetal element 94 which carries contact member 18.

If the increase in the voltage on the generator I2 is a momentary increase then the energization of the operating winding 48 is of only a momentary value with the resultthat the movable contact member 68 is only momentarily in engagement with the fixed contact 64 and the transformer I26 is energized for so short a period of time that the bimetal element 94 which carries the contact member I8 is insufliciently heated to actuate the contact member I8 into engagement with the fixed contact member I4.

However, if the increase in the voltage on generator I2 is of suilicient duration, then the bimetal element 94 which carries the contact member I8 is so heated as to actuate the lower contact member I8 into engagement with the fixed contact member 14. It is to be noted that because of the insulating connector member I28 which connects the bimetal elements carrying the movable contact members, that the bimetal member 84 associated with the contact member I6 is moved at the same rate and in the same direction as the heated bimetal member 94 which carries the contact member I8.

When the contact member [8 is in engagement with the fixed contact member I4, a circuit is closed which extends from the lead conductor I6 through conductors 58 and 68, contact carrying arm 54, contact members 68 and 64, conductors I44 and I48, bimetal member 94, contact members I8 and I4, conductor I52, the operating winding of lower relay 48, and conductors I54 and 52 to the line conductor I8 to energize the operating winding of relay 48. When this circuit is established, the relay 48 is actuated to close the circuit to energize the winding 36 of motor 28 and eifect the operation of the motor 28 to drive the contact arm 32 in a counterclockwise direction. This operation of the contact arm 32 connects more of the rheostat 26 in the field circuit of the generator I8 to decrease the energization of the field winding and thereby decrease the voltage on the generator.

If at any time during the operation of the rheostat motor 28 the increase in the voltage on the generator I8 is removed from the line conductors I6 and I8, then the operation of the motor 28 is substantially instantaneously interrupted by the operation of the primary control device 46 to separate the contact members 68 and 64, thereby effecting the deenergization of the operating winding of the relay 48. Thus, although the initiation of the operation of the rheostat motor 28 is dependent upon the operation of both the primary control device 46 and the thermal time delay device 18, the operation is instantly interrupted by the operation of the primary control device 46 only, even though the thermal time delay device I8 is in a circuit closing position,

If, on the other hand, the change in the voltage in the generator I8 is a decrease, then the energization of the operating winding 48 of pri=.

mary control device 46is so decreased that the contact carrying arm 54 is actuated by the spring 58 in a counterclockwise direction to a position where the raise contact member 62 engages the fixed contact member 66 to close a circuit through the primary winding I38 of the transformer I24. This circuit extends from the line conductor I6, through conductors 58 and 68, contact carrying arm 54, contact members 62 and 66, conductor I48, a primary winding of transformer I24, and conductors I58 and 52 to the line conductor I8.

The energization of the primary winding I38 I of transformer I24 etiects a flow of current through the secondary winding I32 and the bimetal element 94 which carries the movable contact member I6 to heat the bimetal member and cause it to bend to a position where the raise contact member I6 engages the contact member I2. When the bimetal member 94 which carries the contact member I6 is thus actuated, a circuit is closed which extends from the line conductor I6, through conductors 58 and 68, contact carrying arm 54, contact members 62 and 66, conductors I48 and I48, the bimetallic element 84, contact members I6 and I2, conductor I56, the operating winding of "raise" relay 42 and conductors I54 and 52 to the line conductor I8 to effectively energize the relay 42.

When the relay 42 is energized. it establishes a circuit to effect the energization of the field winding 38 of the rheostat motor 28 whereby the motor 26 is operated to actuate the contact arm 82 in a clockwise direction to cut out a portion of the rheostat 26 from the field circuit of the generator I8. Removal of a portion of the rheostat 26 increases the energization of the field winding I4 and thereby increases the voltage on the generator I 8.

Whether the change in the voltage on the generator be an increase or a decrease, the thermal time delay device I8 operates in a similar manner but in a reverse direction, depending upon the direction of the change. Likewise, regard less of the direction of the change, the operation of the rheostat motor 28 is dependent upon the operation of both the primary device and the thermal time delay device but the primary control device operates independently of the time delay device to interrupt the operation of the motor.

The apparatus and system of this invention provides a simplified regulation of voltage requiring a minimum of mechanical parts which may demand maintenance. Further, because of the time delay provided, operation of the regulator is decreased to a minimum, small rapid changes in the voltage of the generator having no effect on the regulator. In addition, provision is made for instantaneously interrupting the operation of the regulator when required by the voltage of the generator to prevent overregulation of the voltage. 7

Although this invention has been described with reference to a particular embodiment thereof. it is.'of course, not to be limited thereto except in so far as is necessitated by the scope of the appended claims.

I claim as my invention:

1. In a regulating system. in combination. an electric circuit the voltage of which is to be regulated, an automatic voltage regulator for said circuit, a control circuit for the regulator, the control circuit including a primary control device connected to respond to the voltage of said circuit, means under the control of the primary control device for controlling theoperation of the regulator, and a thermal responsive time delay device connected in circuit with the controlling meansfor delaying the response thereof to the primary control device, the time delay device and the primary control device being disposed to be connected in series circuit relation with each other and the controlling means whereby the controlling means is dependent upon the operation of both the primary control device andthe time delay device to eiiect the operation of the regulator but dependent upon the operationof the primary control device only to interrupt the operation of the regulator.

2. In aregulating system, i combination, a dynamoelectric machine having a field winding the voltage of which is to be regulated, a rheostat for controlling the energization of the field winding, a reversible motor for operating the rheostat, a primary control device connected to respond to the voltage of the dynamoelectric machine, means under the control of the primary control device for controlling the operation of the rheostat motor, and a thermal responsive time delay device connected in circuit with the controlling means "for delaying the response thereof to the primary control device, the time delay device and primary control device being disposed to be connected in series'circuit relation with each other and the controlling means whereby the controlling means is dependent upon the operation of both the primary control device and the time delay device to effect the operation of the motor but dependent upon the operation of the primary control device only to interrupt the operation of the motor.

3. In a regulating system, in combination, an electric circuit the voltage of which is to be regulated, an automatic voltage regulator for said ciram, a control circuit for the regulator, the control circuit including a primary control device connected to respond to the voltage of said circuit and having separate raise" and lower contact members, means comprising a pair of auxiliary control devices having contact members for: controlling the operation of the regulator and having windings disposed to be selectively connected to the raise or lower contact members of the primary control device, and a time delay device disposed to delay the response of the auxiliary control devices to the primary control device, the time delay device "having a pair of contact members disposed to selectively connect the windings of the auxiliary control device in series circuit relation with an associated contact member of the primary control device, a thermoresponsive element associated with each of the time delay contact members and disposed to actuate it, and means associated with each of the thermoresponsive elements dependent upon 1 the operation of the primary control device for selectively heating the thermoresponsive elements to actuate the control member associated therewith and selectively energize a winding of the auxiliary control devices to control the operation of the regulator, the energization of the winding being dependent upon the establishment of the series circuit connection betweenthe primary control device and the auxiliary control device by the time delay device, the primary control device operating under predetermined conditions ,to interrupt the series circuit independently of the operation of the time delay device to deenergize the winding and interrupt the operation of the regulator.

4. In a regulating system, in combination, an

electric circuit the voltage of which is to be regulated, an automatic voltage regulator for said circuit, a control circuit for the regulator, the

control circuit including a primary control de-,

vice connected to respond to the voltage of said circuit and having separate raise and lower contact members, means comprising a pair of auxiliary control devices having contact members for controlling the operation of the regulator and having windings disposed to be selectively connected to the raise or lower" contact members of the primary control device, and a time delay device disposed to delay the response of the auxiliary control devices to the primary control device, the time delay device comprising a.

contact member associated with 'each of the windings and the primary control contact memberassociated therewith, a thermoresponsive element disposed to actuate each of the time delay contact members, and means associated with the thermoresponsive element and responsive to the operation of the primary control device for heating theelement to effect the actuation of the contact member associated therewith to connect the winding and the primary control contact member in series circuit relation to energize the winding, the primary control device being operative independently of the time delay device when the time delay contact member is in its circuit establishing position to effect the substantially in- ,stantaneous deenergization of the winding to in terrupt the opertaion of the regulator.

5. In a regulating system, in combination, an electric circuit the voltage of which is to be regulated, an automatic voltage regulator for said circuit, a control circuit for the regulator, the control circuit including a primary control device connected to respond to the voltage of said circuityseparate raise and lower contact members for the primary control device disposed to be actuated to a circuit closing position under predetermined operating conditions of the primary control device, a raise and a lower auxiliary control member having a contact member corresponding to'the raise and lower contact members of the primary control device, a winding for each of the auxiliary control members disposed to be selectively connected to the raise and lower contact members of the primary control device to control the operation of the regulator, and a time delay device disposed to delay the connection oi the windings to the primary control contact members to delay the operation of the regulator, the time delay device comprising a raise and a lower" contact member, a thermoresponsive member associated with and disposed to actuate each of the time delay contact members, a transformer electrically connected to each of the thermoresponsive elements disposed to be selectively energizedwhen the primary control device is actuated to a circuit closing position to heat the element connected thereto and actuate its contact member to selectively connect a winding of the auxiliary control device to one of the primary control contact members and thereby efiect the energization of the winding, the primary control device being operative independently of the time delay device when the time delay contact member is in its circuit closing position to effect the substantially instantaneous deenergization of the windingto interrupt the operation of the regulator.

LESTER G..TUBBS.

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