US1498134A - Control system - Google Patents

Description

June 17 -l 924.

W. SYKES CONTROL SYSTEM Filed Jul 'v;

1920 2 Sheeis-Sheet 1 r 1 8 M 1w i M W I ll V U w mwm W MS Q f'ofward b I l I l 6 2 mm 7 m WITNESSES: w

ATTORNEY Patented June 17, 1924.

UNITED- STATES 1,498,134 PATENT OFFICE.

WILFRED SYKES, OF WILKINSBURG, PENNSYLVANIA, AS SIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

common SYSTEM.

Application filed July 7 1820. Serial No. 394,550.

T oall whom it may concern:

Be it known that I, Wrnrnnn Shine, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Control Systems, of which the following is a specification.

My invention relates to systems of control and it has special relation to control equipments for reversing rolling mills and the like.

At the present time. the passes of the metal in a reversing rolling mill are manually controlled in the following manner. The main-rol1motor speed is initially made sufiiciently low to cause the ste'el'to enter the rolls very slowly, in order that the 0 erator may be assured that the billet is properly alined,and located squarely in the groove in the rolls and also for the purpose of avoiding heavy shocks on the mill. The operator then actuates his controller to another position to accelerate the main-roll motor and pass the metal rapidly through the mill. Just before the'end of the piece goes through the rolls, the operator again actuates his controller to .slow down the main-roll motor and cause the steel to leave I the mill slowly. Such procedure requires a skillful operator who must very closely watch the work in order to obtain satisfactory results.

It is the object of my invention, therefore, to render the operation of a reversing rolling mill more nearly automatic than obtains at the present time, :in order to increase the output and decrease the labor cost, while producing more satisfactory operation than is possible under present conditions.

Viewed from another angle, the object of my invention is to render the speed of the main-roll motor dependent upon the.position, or responsive to the weight, of the metal under treatment, whereby the speed of the motor is automaticall increased as the metal reaches the rolls and is automatically decreased just as it leaves the roll.

More specifically stated, one object of my invention is to provide a table-roller device which may. for example, be depresseddur ing the passage of the metal under treatment to close a set of contact members, whereby the main-motor speedis increased.

Other objects of my invention will'become' evident-from the following detailed description, takenni conjunction with the accompanying drawings, wherein- Figure 1 is a view, in side elevation, of

operation of the various switches that are shown in Fig. 4:; and

Fig. 6 is a diagrammatic view of a modification or extension of my invention.

Referring to Figs. 1 to 3 of the drawing, the structure here shown comprises a reversing rolling mill 1 having the usual stands or end-supports 2. for the main rolls 3 and 4.- and which is also provided with the familiar feeding rolls 5 and 6. A plurality of table-rollers 7 are located on each side of the main rolls, in accordance with the usual custom, being driven through the agency of a plurality of bevel gear-wheels 8' which are mounted upon common shafts 9 and 9a for I each side of the mill. These shafts are driven,- through the agency of reducing gean trains 10 and 11, by the table- roller motors 12 and 13, respectively.

The main-roll motor or reversing motor 14 is suitably connected to the main rolls, as by a pinion and gear-whee} 1'5. Uonsequently, the movements or passes of a billet 16, or other metal under treatment, may be controlled, in both direction and speed, by the tabie-roller motors when the billet is at some distance from the main rolls and by the main motor 14 when the billet actually reaches the main rolls 3 and 4.

In addition to the customary table rollers 7, a novel table-roller 2t; is located preferably close to the feeding roll 5 for a special speed-regulating purpose. It will be noted that the roii 20 is normally locat d in a position slightly higher than that of the tablerollers 7, as clearly shown in Fig. 2. The

roller 20 is journaled or supported, at its ends, in a block or bearing member 21 which is adapted. to slide vertically within a stationary bracket or pedestal 22, being biased to the illustrated upper or out-of-alinement position by means of a suitable helicalspring 23, the lower end of which rests upon a bracket or arm 24 forming a art 'of, or

suitably secured to, the main rame-work of the table-roller structure.

A plurality ofspaced contact members 25,

member which is suitably supported by, or

fastened to, the bracket arm 24.

Consequently, depression of the table-. roller 20, in opposition to the action of the biasing spring 23, by the traveling billet, or other metal under treatment, causes the electrical contact of the various illustrated contact members 25 to 30, inclusive, for control pur ses to be set forth later.

A similar depressible roller structure 31 is provided upon thevopposite side of the main I rolls 3 and 4 in a position corresponding to that of the other depressible roller 20. It will be understood that the depressible rollers 20 and 31, which are located on the opposite sides of the main rolls, respectively correspond to forward and to reverse operation of'the mill, only one of them being effective for any given direction of operation.v

Fi 2, in addition to the normal relative location of the various rolls 3', 4, 7, 20 and 31, illustrates a slight modification that is necessary in the customary side-guards that travel across the table-rollers. These guards are indicated by the rectangular figures to which the reference characters 35 and 36 are applied, and it will be noted that a small curved notch or roove 37 is provided in the side-guard 35 ]ust above the depressible roller 20, while a corresponding groove 38 is provided in the other side-guard 36 just above the depressible roller 31. Consequently, the normal operation of the side-guards is not interfered with in any way by reason of the normal out-of-alinement position of the depressible table- rollers 20 and 31.

Referring to the diagram of Fig. 4, the system here shown comprises a main generator which is connected in permanent series relation with the main or reversing mo-.

tor 14, a constant-potential exciter 52 being provided for energizing the single shunt field winding 61 of the generator 50 and also a shunt field winding 63 for the reversing motor 14, while a variable-potential exr citer 53 is employed to energize a variablepotential field winding 62 for the reversing motor 14. i

Aplurality of reversing switches or con tactors 41 and 42 are adapted to be alternately employed for reversing the direction of current in generator field winding 61, and corresponding switches 43 and 44 are utilized for a similar purpose in connection with the motor field winding 62.

A normally open switch or contactor 45 is adapted, when closed, to short-circuit a portion of a resistor 55 that is included in circuit with the armature of the constailt-potential exciter 52, while a pair of normally closed switches 46 and 47 are adapted to shunt or short-circuit a portion of the resistors 56 and 57, respectively, that are con nected in circuit with the main motor field winding 63 and the variable-potential exciter armature 53, respectively.

In actual practice, the sin le contactors 45, 46 and 47 will each pre erably be replaced by a plurality of rogressively operating switches, in accordance with a familiar practice. However, for the sake of simplicity, the single contactors are shown and will be sufiicient to properly set forth the principles of my invention.

Forv efl ecting the initial or primary control of the various machines, a master switch 58 is provided, being adapted to assume a plurality of operative positions a and b in the direction designated as Forward and a and b in the direction designated as Reversed.

It willbe noted that the various contact ,members that are controlled'by the depressible rollers 20 and'31 are connected in circuit with the actuating coils forthe resistorvarying switches 45, 46 and 47, as subsequently described in detail;

Assuming that it is desired to efi'ect forwardoperation of the main or reversing motor 14, the table- roller motors 12 and 13 having also been started into operation, the master switch 58 may be actuated to its initial position b, for example, corresponding to the previously-mentioned automatic adjustable-speed control. If the controller is actuated to its position a only, then a permanently slow-speed operation will be obtained, irrespective of the position of the billet or other metal under treatment, since the contact-closing action of the depressible roller 20 or 31 does not become effective unless the master switch 58 occupies its position b.

Under this condition, one circuit is established from the positive terminal designated by the character of the constantpotential exciter 52, through conductor 65, actuating coil of the switch or contactor 41. conductor 66, and control fingers 67 and 68, which are bridged by contact segment 69 of minal in question, through conductor 71, ac-

tuating coil of the switch or contactor 43, conductor 72 and control finger 73, to the contact segment 69 of the master switch.

The two switches orcontactors 41 and 43 are thus closed, while switches 46' and 47 are normally closed, as indicated in the first forward position of thesequence chart, Fig.

The closure. of the switch 41 establishes a new circuit from the positive terminal of the constant-potential exciter 52, through conductors 74, the entire resistor 55,, since the switch 45 is normally opened, conductors 7 and 76, lower movable contact member 77 of the contactor 41, conductor 78, field winding 61 of the generator 50, conductors 7 9 and 80, upper movable contact member 81 of the contactor 41, and conductor 82 to the negative terminal of the constant-potential exciter 52. In this way, the field winding 61 for the generator is built upto the desired value-and in the proper direction for effecting forward operation of the main motor 14. r

Another circuit is concurrently established from the positive conductor 74, through con:

ductor 83, normally closed switch 46, a portion of the resistor 56, conductor 84, shunt field winding 63 of the main motor 14 and conductor 85, to the negative terminal of the exciter 5 2. The field winding 63 is thus energized at a relatively strong value by reason of the short-circuit of a large portion of the resistor 56 by the switch 46.

The closure of the contactor 43 establishes a circuit, from the positive terminal of the variable-potential exciter 53 through.

conductor 86, contactor 47, a portion of the resistor 57, conductors 87 and 88, upper movable contact member 89 of the contactor 43, conductors 90 and 9,1, field Winding 62 of the main motor 14, conductors 92 and 93, lower movable contact member 94 of the contactor 43 and conductors 95 and 96, to the negative terminal ottthe variable-potential exciter 53. The fieldwinding 62 is thus also energized at a relatively strong value by reason of the short-circuit of a large portion of the resistor 57 by the contactor 47. v

However, in position 5 of the master switch, if either depressible roller .is actuated to its lower position, the contactor 45 is closed, while the contactors 46 and 47 are opened, as indicated. These control operationsoccur follows, be'ag dependent upon the position or i "pensive to the weight of tin biiiet 16 or ;al tier treatment, as

stereo. by rioz'zrnward movement of the one or the other depressible rollers or 31. From the pqsitive conductor 74, one new circuit is establlshedthrough conductor '105, actuating coil of the contactor 45, conductor 106, lower orstationary contact member that is associatedwitli the depressible roller 20, corresponding upper or movable contact member 27, conductors 109 and 110 and control finger 111,.whicl1 is connected to the contact segment 69 of the master switch 58.

' In this way, the contactor is closed as soon as the billet 16 or other metal to be treated reaches the depressible roller 20 and actuates it to its lower or circuit-closing position. By reason of the closure of the switch 45, a portion of the resistor is short-circuited to increase the current in the generator field winding 61 which, in turn, causes the impression of a higher. voltage upon the armature of the main motor 14. Thus, the main motor will accelerate to a new voltage-balancing speed corresponding to the increased voltage upon its armature terminals. However, further. speed increases of the main motor 14 are brought about by the weakening of the shunt field 62 and 63, as about to be described. 1

Another new circuit is established from the positive terminal of the exciter 52 through auxiliary contact member 112 of the switch 45, in its closed position, conductor 112a, actuating coil of the contactor 46, conductor 113, stationary contact member 28 and movable contact member 25, that are associated with, the depressible roller 20, whence circuit is completed through conductor 109 to the negative terminal, as previously traced. The contactor 46 is thus liftedto insert the entire resistor 56 in circuit with the shunt field winding 63 of the main motor. The electrical interlocking of the switches 46 and 47 with the switch 45 prevents loss ofmotor torque by weakening of entire YESlStOF'SZ" in circuit with the va-..

riabie-potentiei field Winding 62 for the main motor 14, thus weakening the exciting strength thereof in approximate proportion to the weakening of the shunt field ing' 63.

Ail

the comic! operatiens gust.

described, namely, the increase in the strength of the generator field winding 61 and the decreases in the exciting values of the motor field windings 62 and 63, tend to ever, the inherent time-element inthe main motor 14, before full-speed conditions are actually attained, is such as to bring about the desired speed* approximately just after the front end of the billet has entered the main rolls 3 and 4. It will be appreciated that the designot. the motor 14, with regard to the distance between the,.depressible roller 20 and the main rolls 3 and 4, may readily be made suchas to provide the desired timeelement in the motor operation.

The roller 20 is,' of course, depressed throughout the passage of the billet 16, thus automatically providing the desired high speed as the billet passes through the mill. As soon as the rear endot the billet passes beyond the depressible roller, the roller springs back to its normal or contactopening position and, consequently, the switch 45 is opened and the switches 46 and 47 are closed, as illustrated in Fig. 4, causing the motor 14 to slow down to the desired speed approximately at the time that the rear end of the billet leaves the main rolls 3 and 4.

In this way, control of the main motor erated in the reverse direction in a similar manner to that hereinbe'fore setforth, to

' cause a reverse pass of the metal through the mill.

For example, a circuit is established from the positive conductor through actuating coil of the switch 42, conductor 121 and control finger 122 to the contact segment 123 of the master switch 58. Furthermore, another circuit is established from the positive conductor 71 through the actuating coil of the contactor 44, conductor 124 and control finger 125 to the contact segment 123.

The field winding 61 for the generator 50 and the field winding 62 for the motor are thus reversed, as will be understood without detailed tracing of the circuits.

Since the control finger 1110: is engaged by the contact segment 123 in position b of the master switch 58, the conductors 1100, 106, 113 and 117 are energized whenever the depressible roller 31 is actuated by the traveling billet. A plurality of lower or stationary contact members 107, 118 and 114, are adapted to engage corresponding movable contact members 108, 119 and 115 which correspond to the previouslydescribed movable contact members 25, 26

and'27. Consequently, the closure of the contactor 45 and the opening of the contactors 46 and 47 occur whenever the roller 31 is'depressed to provide the desired highspeed conditions of the main motor 14 at the proper time, as hereinbefore set forth.

Referring to Fig. 6, the system here shown involves an extension of the automatic idea previously explained, whereby the operation of the main motor may be considered as entirely automatic, since its direction of rotation is automatically governed in accordance with the direction of rotation of the table-rollers.

Fig. 6 shows one method of obtaining this type of control, the master switch 58 for the main motor 14 and 'a-master switch 7 an accelerating resistor 132 therefor, a set of reversing contactors or switches 133 to 136, inclusive, a plurality of resistor contactors or switches 137 and 138, and a line contactor 139.

The motor 12 preferably comprises a commutator-type armature 141,- a series field winding 142, a commutatingfield winding 143 and a shunt field winding 144, which is bridged by the familiar field-discharge resistor 145. p

The direction, as well as the degree of energization of the motor 12, is governed by the master switch or controller 128, which may beof any well-known form. In practice, the master switch 128 usually comprises a pair of mechanically-coupled faceplate controllers, assembled back-to-back, for

governing "the operation of the respective table- roller motors 12 and 13. However, for the sake of simplicity, a drum controller has been illustrated having two sections respectively corresponding to the motors 12 and 13.

The complete control for the motor 12 only is shown. Since the control of the corresponding motor 13 i similar in all respects, it is not deemed necessary to illustrate such circuits. Furthermore, since the particular type of control of the table-roller motors forms no essential part of my present invention. 1 do not deem 1t necessary to describe the operation thereof in detail. It will be suificient to state that the controller 128 comprises a contact segment 147, corre sponding to forward operation of the motor 12, and a contact segment 148,-corresponding to reverse operation thereof, these contact members being adapted to engage a plurality of control fingers 14:9 in a suitable sequence, in accordance with a familiar practice.

Corresponding contact segments 150 and,

151 and control fingers '152 are provided for governing the operation of the other tableroller motor 13, aswill be understood.

' To ensure the proper co-ordinate operation of the master switches 58 and 128 for the main .roller motor and the table-roller motors, respectively, the apparatus is arranged as follows. The switches are equipped with the usual controlling handles 154 and 155. and are further provided with suitable sprockets 157 and 158, for example,

which maybe rigidly attached to the operating shafts'159 and 160 of the respective controllers. around the two sprockets 157 and 158, whereby the desired concurrent operation of both switches, by moving, for example, the one handle 155 for the table-roller controller 128, is ensured."--

The gear ratio between the two,,controller shafts 1s, of course, determined by the relative size of the sprockets and is preferably such that each controller reaches its final position at approximately the same time.

7 In other words, the operation of the tableemployed in lieu thereof, if desired. For

.roll shaft of the plate mill. would be arranged to fall between two of the exam le, in the case of plate mills, it might be we 1 to provide a roller that is supported onjan arm which is;mounted upon the up er Thls ro er table rollers so that metal reachingit would lift it up slightly to make the nepes'sary electrical contacts, in accordance withthe previous description.

Furthermore, it will be understood that, if desired, more than one step of automaticallyvaried control may be obtained by providing more than one depressible roller upon each.

side of the main rollers, whereby different values of field-circuit resistance are cut into or out of circuit, as desired. Consequentl I do not wish to be restricted to the speci c structural details, circuit connections or ar- A chain 161, or the like, passes rangement of parts'herein set forth, as various modifications thereof may be elfected within the spirit and scope of my invention. I desire, therefore, that only such limitations shall-be imposed as are indicated in the appended claims.

I claim as my invention:

'1. In a control system for rolling mills, the combination with a motor for driving the rolls for rolling the metal under treatment, of means dependent upon the position of one end of said metal for varying the speed of said motor.

2. In a control system for rolling mills, the combination with a motor for driving the rolls for rolling the metal under treatment, of means engaged by one end of the traveling metal for increasing the motor speed as the metal enters therolls.

3. In a control system for rolling mills, the combination with a motor for driving the rolls for rolling the metal under treatment, of means responsive to, the weight of said metal for increasing-the motor speed asthe metal enters and decreasin the motor speed as the metal leaves the ro s.

4:. In a control system forrolling mills,

the combination with a motor for driving the rolls for rolling the metal under treatment, of a device. adapted to be actuated in opposite directions asthe respective ends of t e metal approach the mill for varying the motor spee 5. In' a control system for rolling mills, the combination with a motor for driving the rolls for rolling the metal under treatment, of a contact-making device adapted to be depressed and lifted as the respective ends of the metal approach the mill for varying the motor speed.

6. ha control syste'i'nfor rolling mills, the combination with a motor for driving "the rolls for rolling the metal under treatment, of a shiftable table-roller for ing the operation of said motor.

7. In a control system for rolling mills, the combination with a motor for driving the rolls for rolling the metal under treatment, of a depressible table-roller for ingovern- :creasing the motor speed as the metal enters the rolls. a

8. In a, control system for rolling-mills,

the combination with a motor for driving the rolls for rolling the metal under treatment, of a .bodily movable table-roller, and a circuit closed upon actuationthereof for governing the motor operation.

9. In a control system for rolling mills,

"the combination with a motor for driving the rolls for rolling the metal under treat ment, of a depressible tablemoller, and a circuit closed upon actuation thereof for increasin the motor speed.

10. n a control system for rolling mills, the combination with a motor for driving the rolls for rolling the metal under treatment, of a depressible table-roller for controlling the excitation of said motor and spaced from said rolls such a distance that the time element required for the work to proceed from the depressible roller to the rolls'will bes'ufiicient to change the motor speed by a predetermined amount. I

11. In a control system for rolling mills, the combination With a motor for driving the rolls for rolling the metal under treatment, of means ,engaged by the traveling metal for controlling the operation of said motor and spaced from said rolls such a dis- 'tan'ce that the time element required for the work to proceed from said means '[Olllle rolls will be suflicient to increase the motor speed by a predetermined amount.

12. In a control system for rolling mills, the combination with a motor for driving the rolls for rolling the metal under treatment, said motor having a shunt field winding, of a table-roller normally out of alinement with the remaining table-rollers, and switching means closed by movement of said roller to the alined position for reducing the strength of said field Winding.

13. In a control system for rolling mills, the combination with a motor for driving the rolls for rolling the metal under treatment, and a table-roller motor, of means for ensuring "the operation of themain rolls and of the table-rollers in the same direc' tion. and means dependent upon the position of the metal for varying the operation of one of said motors.

14. In a control system for rolling mills,

the combination with a motor for driving ment, and a table-roller motor, of a plurality of controllers for governing the respective motors, a single operating handle for eifecting movement of both controllers to the re spective final positions, corresponding to slow-speed o ration of the main-roll motor, and a de pre'ssible table-roller for increasing the main-roll motor speed as the metal enters the rolls.

In testimony whereof, I have hereunto subscribed my name this 22nd day of June, 1920.

WILFRED sYKEs,

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