US1493968A

US1493968A - System of distribution

Info

Publication number: US1493968A
Application number: US424058A
Authority: US
Inventors: Rae W Davis
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1920-11-15
Filing date: 1920-11-15
Publication date: 1924-05-13
Anticipated expiration: 1941-05-13

Description

R. W. DAVIS SYSTEM OF DISTRIBUTION May .13 1924. 1,493,968

Filed Nov. 1 1920 25 26 v 2 Sheets-Sheet. 1

May 3 1924.

- 1,493,968 R. w. DAVIS.

SYSTEM OF DISTRIBUTQTON 2 Sheets-Sheet 2 Filed Nov. 5, 1920 Patented May 13, 1924.

UNITED STATES PATENT owner. I

m w. DAVIS, 01' AIJLIS, WISCONSIN, ASSIGNOR- TO ALLIS-CHALMERS MANU- FACTURING COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF 1mm.-

WARE.

srs'rnm or ni's'rmurron.

Application filed November 15, 1920. Serial Nb. 424,058.

To all whom it may concern: I

'Be it known that RAE W. DAVIS, a citizen of the United States, residing at West Allis, in the county of Milwaukee and State of \Visconsin, has invented a certain new and useful Improvement in Systems of Distribution, of-which the following is a speci-- fication.

This invention relates to systems of distribution and more particularly to such systems involving the use of motors operating in conjunction with energy storing means such as flywheels. The invention is applicable in cases where the rolls of a' mill, as in a steel mill, are driven by electric motors. In cases where the work driven by electric motors fluctuates widely and the load sometimes rises to excessive values it becomes desirable to provide a store of energy which maybe drawn from to take care of such excessive loads. It is clearly desirable that the stored energy shall be of considerable amount to adequately take care of predetermined excesses. It is a rather difiicult problem however, to economically design a flywheel unit which will take care of the load excesses frequentlyoccurring in a steel mill. It is one of the objects of this invention to provide means whereby this problem 1s solved in an economical and efficient manner.

It is customary in connection with the electric drive of steel mills and the like to utilize two or more motor units.' It is one of the objects of this invention to provide means whereby the flywheel capacity of both units is made available when a load is put upon either unit. Another object of the invention is the provision of a system whereby the size and weight of the flywheels'necessar in such an installation will be reduced.

, nother object is the provision of a system' in which the power demands from an electric supply line for the units will be equalized.

Another object is the provision of a system in which the loads on the motor units will be equalized so that each unit will take some of its energy. Other objects will ap-' pear hereinafter as the description of the mvention proceeds.

The novel features of the invention will appearfrom this specification and the accom anying drawings forming a part thereof sliowing several embodiments of the in-.

vention, and all these novel features are inmainder of the system may, if desired, be

the same as in Fig. 1.

Referring more particularly to Fig. 1,.the invention is here shown as it may be ap lied in connection with two-work motor unlts 1, 2 each of which may be connected in a suit.- able manner to driverolls of a steelmill igs. 2, 3 and 4 are modified forms or the like. The system further comprises two flywheel motor-generator sets 3, 4. The motor unit 1 includes two motors 5, 6 connected in series by a conductor 25. This motor unit is connected in series with the

generators

7, 8 of the motor enerator sets 3, 4 respectively by means of the

conductors

26, 27 and 28. The motor unit 2 com rises motors 9, 10 connected in series by con uctor 29. .This motor unit is connected in series with generators 11', 12 of the motor generator sets 3, 4 respectively by means of

conductors

30, 31, 32.

The generators 7, 11 of set 3, along with a flywheel 13, are driven by a motor 14, here shown as of the wound rotor induction type. Power is supplied to motor 14 through leads 15 connected to the three hase supply line 16. The motor 14 is provided with slip rings 17 here shown as connected to the electrodes .18 of a liquid rheostat provided with a weir 19 of shutter type. The-operation of rheostats of this type is well known and need not be herein described. It may be further stated that the rheostat in question is shown merely by way of example, it bein under-. stood that the resistance across the s ip rin 17 may be varied through any other suitab e means. The shutters ofthe weir have associated therewith a counter-weight 20 which is so ositioned as to normally tend to close the s utters thereby permitting the electrode-containing receptacle to be filled with electrolyte for the purpose of reducing the resistance across the slip rings of the motor. The weir is operatively connected to the torque motor 21 and the relation is such that when the torque of said motor increases the counter-weight 20 will be lifted so that the shutters of the weir are opened to a predetermined extent, thereby 1ncreasing thether description of this controlis therefore necessary.

The

field windings

33, 34 of the motors 5, 6 are preferably connected in series with each other and with a rheostat 35, the circuit thus formed being connected to and fed from the

exciter buses

36, 37, in turn connected to the exciter 38. The field windings 39, of the motors 9, 10 are in like manner connected in series with each other and with a rheostat 41 and also fed from the

buses

36, 37.

The field windings 42, 43 of the generators 11, 12 respectively, are preferably connected in series with each other and with a -rheostat 44 through a reversing switch 45 to the

buses

36, 37. The field windings .46, 47 of the

generators

7, 8 respectively are in like manner connected in series with each other and with the rheostat 48 through a reversing switch 49 to the

buses

36, 37. It

must be understood, however, that the control means for the field windings of the motors and generators may be elaborated and varied to satisfy the particular conditions confronted and the results desired to be obtained.

The operation of the system disclosed in Fig. 1 is as follows: Inasmuch. as the motor unit 1 is supplied b a generator on each of the sets 3, 4, any oad which is put upon said motor unit will necessarily be supplied by power from both sets. The same is true of motor unit 2. In case there should be a particularly heavy draft on motor unit 1, for example, the flywheel capacity of both sets will be available. By reason of the fact that one generator on each set supplies each given motor unit there will be an inherent tendency to equalization of the loads on the flywheel motor generator sets because if for any reason the speed of one set should become materially lower than that of the other the generator operating at the higher speed will take a greater part of the load than the one at the lower speed. This inherent regulation is augmented by the control system for the driving motors of the motor generator sets for when an additional current is supplied to either one of the driving motors the rheostat-control tial features and connections of the

motor units

1, 2 and

generators

7, 8, 11, 12 as shown 1X1 Fig. 1 will be substantially the same when the

driving motors

14, 24 are controlled as shown in Fig. 2. Parts in Fig. 2 similar to those in Fig. ,1 have been given the same reference numerals as far as advisable, for the sake ofclearness. The weirs 19 of the rheostats controlling the

motors

14 and 24 respectively are controlled by

torque motors

21, 58 and fed by

series transformers

22, 60 respectively. Each weir has a counter-weight 68 associated therewith and positioned so that the weight will normally tend to open the weir. The torque motors are so related to the weirs that upon an increase in torque the counterweight will be lifted resultin in closure of the weirs to a predetermined extent. The torque motor 21, connected to transformers 22 by conductors 51, 52, 53, is provided with slip rings 54, said motor being here assumed to be of the wound-rotor induction type. These slip rings are connected to

resistances

55, 56, 57. What has been stated in connection with torque motor 21 also applies .to torque motor 58 the slip rings of which are in like manner connected to a set of three resistances. A difi'erential relay 61 is provided and comprises opposed coils 62,

The coil 62 is here shown as connected cally connected. Associated with the core 64 1s a member66 provided with electrically connected contacts co-oporable with the resistances55, 56, 57. The core 65 is in like manner provided with a member 67 having contacts co-operable with the similar resistances associated with the torque motor 58.

The operation of the control system disof the torque motor 58. The loss of torque in the torque motor 21 will permit the counter-weight 68 to open the associated weir 19 to a predetermined extent thereby increasing the resistance across the slip rings'17 and reducing the speed of motor 14 so that the flywheel associated therewith will be permitted to ive up a predetermined amount of energy. The reduction of resistance in the rotor circuit of torque motor 58, on the other hand, will cause an increase of torque which acting against the counter-weight 68 will cause a predetermined closure of the associated weir 19, thereby decreasing the resistance across the slip rings of motor 24 and increasing the speed of the latter so that it will take the increased load put upon it.

In the modification shown in Fig. 3 the motor 14 has its rheostat-weir means of torque motor 69 supplied through leads 72 connected to the serles transformer 60 associated with the main leads ofmotor 24. The motor 24 on the other hand has the weir of its rheostat 73 controlled by means of a torque motor connected through leads 71 to the series transformers 22.

The operation of the system discloesd in Fig. 3 is as follows: Assumin that the motor 24 is taking a heavy load t e current in series transformer 60 will cause an increase of torque in tor ue motor 69 thereby causing the latter to 1i t the counter-weight 20 to open the weir to a predetermined extent thereby acting to slow down the speed of motor 14. The resulting reduction in current in the leads 15 will cause reduction in the torque of motor 70 permitting the counter-weight 20 of rheostat 73 to close the weir .a predetermined extent whereby the torque and speed of motor 24 are increased to enable it to carry its load.

In the modification shown in Fig. 4 the motor 14 has its rheostat controlled by means of a torque motor 21 connected to the series transformers 22. The rheostat of motor 24 is controlled by means of torque motor 74 connected to series transformers 60. In each instance the counter-weight 20 of the rheo-- stat is so positioned as to normally tend to close the weir. Each torque motor isso related to its associated weir than an in crease of torque will tend to lift the counterweight thereby opening the weir in question to a predetermined extent. in this modification the torque motors are mechanically connected by any suitable means as by a rod controlled by 76. As a result of this construction the weirs of both rheostats must always be opened or closed the same amount. It is c ear that if either

motor

14, or 24 is loaded to a greater extent than'the other the associated torque motor will increase its torque, but as the torque motors are mechanically connected a load on one of the main motors will result in an o ening of the weir associated with the un oaded main motor to an extent equal to that of the weir of the loaded main motor, whereby each flywheel is caused to assist in the carrying of the load.

It should be understood that it is not desired that the invention claimed be limited to the exact details of construction shown and described herein, for obvious modifica tions will occur to a art.

It is claimed and desired to secure by Letters Patent:

1. In combination, a work motor, two induction motor-driven flywheel generator sets, said generators being connected in series to sup ly said motor, and a slip regulator for eac of said induction motors.

2. In combination, a work motor, two generators connected in series for supplying said motor, each of said generators having a flywheel associated therewith, and means whereby the flywheel operating at the higher speed is caused to give up energy.

3. In combination, a work motor, a plurality of flywheel generator sets for supplying said motor, and means whereby t e flywheel capacity of all sets is made available when said motor takes a load.

4. In combination, two flywheel generator sets, each set comprising two generators, a work motor sup lied by a generator on each set, another wor lr motor supplied by the remaining generators on sai sets, and means whereby the flywheel capacity of both sets is made available when either when either of said motors takes a load. 5. In combination, a work motor, two motor-driven flywheel generator sets connected in series for supplying said work motor, and means for regu ating the speed of one of said drivin motors in accordance with the load on sai work motor.

6. In. combination, a work motor, two motor-driven flywheel enerator sets connected in series for supp ying said work motor, and means for causing the s eed of the driving motor running at the higher speed to drop a predetermined amount.

7. In combination, a work motor, two motor-driven flywheel enerator sets connected in series for supp ying said work motor, and means efl'ective to maintain said driving motors at substantially the same relative speed.

8. In combination, a work motor, two motor-driven flywheel generator sets conperson skilled in the nected in series for supplying said work motor, and means efiective to cause said driving motors to each take a share of: the load substantially in proportion to their capacities.

9. In combination, two motor-driven fiywheel generator sets, each set comprising two generators, at work motor supplied by a generator on each set, another work motor supplied by the remaining generators on said sets, and means for regulating the speed of one of said driving motors in accordance with the load on said work motor.

10. In combination, two motor-driven flywheel generator sets, each set comprising two generators, a work motor supplied by a generator on each set, another work motor supplied by the remaining generators on said sets, and means for causing the speed of the driving motor running at the higher speed to drop a predetermined amount.

11. In combination, two motor-driven flywheel generator sets, each set comprising two generators, awork motor supplied by a generator on each set, another work motor supplied by the remaining generators on said sets, and means eiiective to maintain said driving motors at substantially the same relative speed. I

12. in combination, two motor-driven flywheel generator sets, each' set comprising twogenerators, a work motor supplied by a generator on each set, another work motor su plied by the remaining generators on said sets,-and means efiective to cause said driving motorsto each take a share of the load substantially in proportion to their capacities.

means for equalizing the speed of said motors comprising means for. reducing the speed of the motor running at the higher speed in response to the load on the other motor.

15. "in combination, a pair of motors, fed from the same source of electricity, means for equalizing the speed of said motors comprising means for reducing the speed of the motor running at the higher speed in response to the load on the other motor.

16. in combination, a work motor, two

induction motor-driven flywheel generator sets, said generators being connected in seriesto supply said motor, and means including a. slip regulator for each of said induction motors for reducing the speed or the induction motor running at the higher speed. v

17. In combinatioma plurality of work motors, a plurality of fly-wheel generator sets for supplying said work motors, and meanswhereby the fiy-wheel capacity of all oi said fly-wheel generator sets is made available when any one or all of said work motors takes or take a load.

in testimony whereof, the signature or the inventor is afixed hereto. 7

" RAE W. DAVIS.