US2026600A

US2026600A - Well drilling system

Info

Publication number: US2026600A
Application number: US678235A
Authority: US
Inventors: Wilkinson Nathan
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1933-06-29
Filing date: 1933-06-29
Publication date: 1936-01-07
Anticipated expiration: 1953-01-07

Description

Jan. 7, 1936.

N. WILKINSON WELL DRILLING SYSTEM 3 Sheets-Sheet 1 Original Filed June 29, 1933 Jan. 7, 1936. I w soN 2,026,600

WELL DRILLING SYSTEM Original Filed June 29, 1933 3 Sheets-Sheet 2 Jan. 7, 1936. w 5 N 2,026,600

WELL DRILLING SYSTEM Original Fild June 29, 1933 s sheets-sheet 5 Patented Jan. 7, 1936 UNITED STATES PATENT OFFICE 2,026,600 WELL DRILLING SYSTEM Application June 29, 1933, Serial No. 678,235 Renewed February 13, 1935 22 Claims.

This invention is in part a continuation of the application of Nathan Wilkinson, Serial No. 512,899, filed February'Z, 1931, for a Power transmission system. No claim is made herein to the system of motor and generator control of general application herein disclosed inasmuch as claims of such character .appear in the above identified application and in application Serial No. 10,155, flied March 9, 1935, which is a division of the present application.

This invention relates to power transmission systems and control therefor. It may be used in connection with the operation of a power driven tool and more particularly in connection with apparatus for drilling holes. It is especially adapted for use with rotary oil well drilling rigs.

- A large number of different operating conditions are encountered in the drilling of oil wells.

Itis accordingly an object of the invention to' provide a power transmission system which is flexible, enabling it to meet the varied operating conditions. A more specific object is the attainment of such flexibility with'a minimum of cost; and also with a maximum of reliability.

A further object is the provision of an electric power transmission system in which internal combustion engines are used as prime movers,

and further, in which close regulation. of engine speed is not required. A more specific object is the provision of such a system in which two engines are used each one automatically carrying its proportion of the total load.

In connection with oil well drilling apparatus of the type in which water is pumped into the drill hole, it is an object to provide a system of power transmission in'which either the pump motor or the drill motor may be started, stopped and otherwise controlled, without afiecting the other motor.

Still another object isthe provision of a power transmission system in which all of the drilling and pumping operations and all of the ordinary and usual hoisting operations may be performed with either one prime mover in operation, or more than one.

Still another object is the provisio'n of a well drilling system in which one or more of a plurality of electric motors are used to selectively drive the hoisting, pumping, and drilling mechanism, the

energy for the motors being selectively furnished by one or more of a plurality of engine driven generators which are preferably of diflerent capacities.

A further object of the invention is the provision of awell drilling system in which one or more of a plurality of electric motors are used to selectively drive the hoisting, pumping, and drilling mechanism, the energy for the motors being supplied during certain operations from all of a system of the above character with a-plurality I of engine driven generators each having a rheostat for controlling the excitation of the field winding thereof, and more specifically the provision of clutch devices forrendering all of said rheostats simultaneously operable during certain operations and for rendering said rheostats operable in pairs during other operations.

Other objects will appear hereinafter as the description of the invention proceeds.

The novel features of the invention will appear from this specification and the accompanying drawings showing one embodiment of the invention and all these novel features are intended to be pointed out in the claims.

. In the drawings:

Fig. 1 is a diagrammatic showing of one embodiment of the invention with particular rela-. tion to the electrical control features thereof.

Fig. 2 is a more or less diagrammatic elevation of mechanical features of one type of oil well drilling rig in connection with which the invention may be used.

Figs. 3 to '7 inclusive are diagrams of various electrical power connections which may be obtained with the system shown in Fig. '1.

Fig. 8 is a diagrammatic showing of an improved embodiment of the invention with particular relation to the electrical control features thereof.

Figs. 9 to 13 are schematic diagrams showing various electrical power connections which may be obtained with the system shown in Fig. 8.

Referring to Fig. 1' of the drawings a prime mover I is here shown as connected to a pair of

i generators

2, 3. The generator 2 is diagramits terminals connected respectively to conductors 9 and Ill. The embodiment of the system here shown includes a pair of intermediate conductors II, II. The conductor II is connectable to the conductor 1 by means of a contactor l3, and is also connectable to the conductor 3 by means of a contactor I4. The conductor I2 is connectable to the conductor 3 by means of a contactor I5, and is also connectable to the conductor I. by means of a contactor it.

Where two sets of engines and generators are 'utilized as in the illustrative embodiment, the

generator 5 may have one of its terminals connected to conductor 3 and the other terminal maybe connected to a conductor H. The generator 8 may have one of its terminals connected to conductor I3 and the other to the conductor l1.

It will be evident as the description proceeds that more than two sets of engines and generators may be utilized. Where two or more sets of generators are used, the generators of like capacity may be used in series.

A pair of conductors I 3, I3 is provided which are connected respectively to the blades of

switches

23, 2| which are both of the single pole double throw type. The switch 23 is adapted to connect the conductor l8 to either he conductor 1 or the conductor 3. The switch 21 is adapted to connect the conductor It to either the conductor 3 or the conductor l1.

The conductor I3 is connected, through a time element overload relay coil 22, to a bus 23. whereas the conductor I3 is connectable through a contactor 24 to a bus 28. One or more motors may be connected to the

buses

23, 23, two

motors

26, 23 being here shown. The motor 23 is connectable to

buses

23, 25 by a switch 21, operating in unison with which is an auxiliary contact 53 for a purpose which will appear hereinafter. The motor 28 is connectable to the

buses

23, 25 by a .switch 23 which-also includes an auxiliary switch Another motor 33 is here shown as having its terminals connected to the blades of a pair of single pole double throw switches 3|, 32 respectively. The switch 3| is adapted to connect one terminal 01' motor 33 to either the conductor H or the conductor l2. The switch 32 is adapted to connect the other terminal of motor to either conductor 12 or to conductor 11. Interposed in one of the conductors leading from one of the terminals of motor 30 is the coil of a time element overload relay 33 which is in a circuit to be described hereinafter.

An exciter 33 is here shown as connectable to the

buses

34, 35 which serve to feed the operating coils oi the various contactors and the field windings of the generators and motors'as will be described in detail.

The field windings 4|, 44 of the generators 2 and I respectively are here shown as controllable by a pair of reversible potentiometer rheostats 31, 33 respectively. One set of terminals of the potentiometer rheostats 31, 33 are connected by means of a conductor 33 through the contacts of the overload relay 22, to the bus 34. The other set of terminals oi the rheostats 31, 33 are connected to the bus 35.- The movable contacts of rheostat 31 are connected by means of

conductors

33, 43 to the terminals of field winding 4|, which latter is here shown as shunted by a resistance or rheostat of any desired form. The

movable terminals of rheostat 33 are connected by means of conductors .42, 43 to the terminals of field winding 44, which is also here shown as shunted by a resistance or rheostat. For many of the conditions of operation the movable members of rheostats 31 and 33 may be operated in acaaeoo unison but it it is desired to operate these rheostats separately a coupling Ill may be disengaged. Operable in unison with rheostat 38, and of course with rheostat 31, is shown a contact 45 cooperable with a ring contact 48. The contact 5 45 is connected to the bus 35. The ring contact 46 has a gap 41 therein in such position that when the rheostats 31, 33 are in thefofl position the contact 45 does not engage the ring 46. For the sake of simplicity only one ring 46 and contact 45 0 have been shown butii desired there may be one such ring and contact not only for rheostat 33 but also for rheostat 31, this being a mere duplication oi parts.

The ring 46 is connectable through conductors 15 43, 43 and the auxiliary switch 53 to one terminal of a field winding SI for the motor 28. The other terminal of the field winding ii is connected to bus 34. The ring 43 is also connectable through a conductor 52 and the aux- 20 iliary switch 53 to a field winding 54 of the motor 26, the other terminal of said field winding being connected to bus 34. The conductor 43 is connected by a conductor It! to a contact 33 with which latter blade 3| of switch C is cooperable.

The

field windings

64 and 64 of

generators

3 and 6 respectively are also here shown as controllable by reversible potentiometer rheostats 51 and 58 respectively. One set of terminals of the resistances of the rheostats 51, 53 are connectable 0 by means of a conductor to the bus 34. The other set of terminals of said resistances is connected to bus 35. Interpcsed in the conductor 55 are the contacts of the overload relay 63 and the contacts oi. a relay 53. The movable contacts 0t 35 rheostat 51 are connected by conductors 53, 60 to the terminals of field winding ii, and the movable contacts of rheostat 53 are connected by

conductors

62, 63 to the terminals of field winding 64. Said field windings may be shunted by resistances m as shown. Similarly as described in connection with rheostats 31 and 33, there is here shown one contact ring 66 with which a contact 35 operable in unison with rheostat 53 cooperates. The ring 66 also has a gap 61 so that when the rheostat 53 L5 (or the rheostat 51) is in the ofi." position, the contact will be out of engagement with the contact 33. A coupling 2 may also be provided between the rheostats 31 and 58 for reasons as stated in connection with rheostats 31 and 33. 30 The ring 36 is connected through a conductor HI to a contact 34 of a master control switch C. The contact 35 is connected to the bus 35.

Cooperable with contact 34 is a switch blade ll of master switch C, which blade is connected by 56 means of a conductor 63 to one terminal of a field winding 10 for the motor 30. The other terminal of said field winding is connected to the bus 34, and said field winding may also be shunted by a resistance as shown. 60

The operating coil ior contactor 53 has one terminal connected to conductor 55 and the other terminal connected through a contact 1| to the bus 35. The contact 1| is controlled by means of a lever 33 which will be further described here- 55 inaiter in connection with Fig. 2.

The operating coils of contactor-s l3 and II are here shown as in parallel and interposed in a conductor 12 one end of which is connected to bus 34 and the other end of which is connected to a contact 13 of the master control switch C.

A blade 14 of the switch C is connected to bus 35, and is cooperable with contact 13.

The operating coils of contactors l4 and ii are here shown as in parallel and interposed in a conductor 15 one terminal of which is connected to bus 34 and the other terminal of which is connected to acontact 16 of the switch C. The blade 14 of the switch C is also cooperable with the contact 16.

The operating coil of contactor 24 is interposed in a conductor 19 one terminal of which is connected to bus 34 and the other of which is connected to a contact 18 of the. switch C. Cooperable with contact 18 is a blade 11 of the master switch C. The blade 11 is also electrically connected by conductor 60 with the blade 14, and therefore also to bus 35.

For a purpose which will appear in connection with the description of the operation of the system, a switch 85 is provided for bypassing the contactor 24. The switch is, under the usual operating conditions, open.

Referring now to Fig. 2, this shows in more or less diagrammatic form an oil well drilling rig of the rotary type with which the invention may be utilized. It is to be understood that the particular form of mechanical drilling rig is shown only by way of illustration so that one way in which applicant's invention may be utilized may be better understood. The drilling rig here shown comprises a hollow drill 86 around which'is disposed a casing 81 which is sunk around the drill as the drilling proceeds. The drill 86 may be rotated in any suitable manner by means of a gear 88 driven by a bevel pinion 89 from a shaft 90. The

shaft 90 may be connected to a driving chain 92 by means of a clutch 9| operable by a lever 95.

The driving chain 92 is in operative relation to a shaft 93 which is in turn driven by a driving chain 94 from the motor 30 which corresponds to the motor 30 in Fig. 1. A shaft 96 is provided which carries fast thereon a winding drum 91. The shaft 96 may be connected to a driving chain I by means of a clutch 98 operable by a clutch lever 99. The clutch lever 99 is operatively related to the switch H which corresponds to the switch of same number in Fig. i, and it will be apparent that when the clutch 98 is disengaged the switch H is closed. A brake IOI is provided for the drum 91, which brake is operable by means of a brake lever I02.

The winding drum 91 is adapted to receive a cabie I03 which runs to the top of a derrick I04 and is )flSSCd over suitable-pulley blocks or sheaves at th: top of the derrick and also over a sheave operatively related to the drill rod 86, so that the winding drum 91 may be used to hoist and lower the drill rod 86, or other desired parts. The drill rod is here shown as connected by means of a flexible hose I to a pipe I06, in turn connected to a pair of pumps I01, I08 of any suitable form. The pumps are here shown as driven respectively by the

motors

26, 28 which correspond to those of the same number in Fig. 1.

The operation of the system will be best understood by a consideration of various power set- I ups that may be secured therewith.

If it is desired to hoist the drill rod 86, or any other part attached to the hoisting cable I03, at full speed, the motor 30 is connected to the large generators 2, 5 in series, as indicated in Fig. 3, as follows: It is assumed that the exciter 33 is connected to the

buses

34, 35, and that the hoisting drum 91 is connected to the shaft 93 by means of the clutch 98. The switch 3I is thrown to its upper contact and the switch 32 to its lower contact. The master switch C' is thrown to the left, as viewed in the drawings, thereby connecting I the blades 14 and 8| to the contacts 13 and 83 respectively. It will be noted, incidentally, that the contact with which the blade 11 contacts, in this position, is, in the illustrative embodiment, a dead contact. With the master switch C in the position stated the contactors I3 and I5 have their operating coils energized and are closed. It may be noted that in the illustrative embodiment and in the particular set-up now under consideration the contactor I5 will not be in any circuit. It will be also noted that while the blade 8| is in engagement with the contact 83 the field winding circuit for the motor 30 is not as yet completed since the contact 45 is, in the starting position, not in contact with the ring 46. The generator field winding rheostats 31, 38 may now be operated to increase the electromotive force generated by generators 2 and 5. also thereby closing the field winding circuit for motor 30. It

is of course clear that the motor 30 will operate in a directiondependent upon which direction the rheostats 31 and 38 have been moved. The provision of differential series field windings H3, H4 for generators 2, 5 respectively, gives these machines .drooping characteristics, which coacts with the method of speed control of

motors

30, 26 26 and 28 by generator field excitation to give good starting torque and acceleration control.

With the set-up of Fig. 3 described above the motor which may be say a 400 H. P. motor operating at'1000 R. P. M. at 350 volts with a 30 peak load of say 600 H. P., is fed from the two large generators which are say of 200 k. w. capacity each operating at 1200 R. P. M. and gencrating 175 volts each. The engines I, 4 are rated at 385 H. P. each at 1200 R. P. M. The foregoing figures are given merely by way ofex ample as are also the ratings of other machines ""to be hereinafter noted. It will be obviousthat the invention is in no way limited to the selection or use of machines of the ratings, voltages and speeds herein given and that those skilled in the art may easily make a choice of ratings etc. suitable to meet any particular conditions. The ratings given in this specification are cited merely to further bring out the possibilities and- 5 flexibility of the disclosed system.

The engines I and 4 are provided with the usual governors (not shown) so that if desired the speeds of these engines may be kept at substantially 12 00 R. P. M., as in the above cited example, or at any other selected speed, as will be understood by those skilled in the art.

If it is desired to hoist at half speed the electrical set-up of Fig. 4 may be secured, by throwing both the switches 3I and 32 to their upper positions. The mechanical set-up of the parts of Fig. 2 are the same as described in connection with the set-up of Fig. '3, and the master switch is also in the same position. It will be noted, however, that since in the set-up of Fig. 4 the motor 304s operating from generator 2 only, that the contactor I5 is now in the circuit feeding motor 30. With this set-up the engine I is the only one in operation-and may operate as before with 385 H. P. at 1200 R. P. M. The 200 k. w. generator 2 now feeds the motor 30 at 175 volts and therefore the motor runs at half speed. that is, 500 R. P. M.

If for any reason it is desired to hoist at half speed with the,motor 30 fed from generator 5, 71) the electrical set-up will be the same as in Fig.

4, but to secure the same the switches 3I and 32 are both thrown onto their lower contacts. The contactor I5 is here again in circuit with the motor 30, and of course the master switch C remains in the same position as for the set-up in Figs. 3 and 4.

It will be noted that with the hoisting set-ups as hereinbefore described in which the lever 88 has been thrown to cause engagement of the clutch 88, the switch 1| is opened, thereby deenergizing the contactor 58. The opening of this contactor opens the circuit of rheostats 81 and 88 and prevents current from being fed to the field windings of generators 8 and 8.

If it is desired to rotate the drill 88 and pump water down through the drill at the same time, the clutch 88 is thrown out (thereby closing switch 1|) and the clutch 8| is thrown in so as to connect the driving shaft 88; for rotating the drill, to the shaft 88. The switch 8| is thrown to its upper position and the switch 82 is thrown to its lower position. The

switches

28 and 2| are thrown respectively to their upper and lower positions. The master switch C is thrown to its right hand position, thereby energizing the operating coils of contactors I4 and It, by reason of the engagement of blade 18 with contact 16. It will be incidentally noted that contactor It will not be in any circuit in this particular set-up. The engagement of blade 11 with contact 18 energizes the operating coil of contactor 24. If it is desired to use both pumps I81 and 188, both

switches

21 and 28 are closed thereby connecting the armature circuits of

motors

28 and 28 to the conductors 1 and I1. While the

auxiliary switches

88 and 58 are closed it will be noted that the circuits for the field windings 58 and 8| are incomplete since at the start contact 45 is not in engagement with ring 48. The rheostats 81 and 88 may now be operated in the proper direction thereby causing the generators 2 and 5, in series, to feed the

pump motors

26, 28 as shown in Fig. 5. Inasmuch as the contact 1| is closed, the relay 88 is energized and therefore operation of the rheostats 51, 58 will supply current to the field windings of generators 8 and 8. The engagement of contact 88 with ring 88 causes the field winding 18 of motor 88 to be supplied with current.

It will be evident that with the set-up of Fig. 5 the motor 88 may be used at full speed for the drilling operation since it is fed from the generators 8 and 8 in series. By way of example, the generators 8 and 8 may be of 40 k. w. capacity each at a voltage of 125. For this drilling and pumping operation the engines 1 and 4 mayhave their governors set to operate at say 850 R. P. M., the engines producing at that speed say 280 H. P. The motor 88 may then operate at say 710 R. P. M. at 250 volts and produce say 100 H P. The larger generators 2 and 5 operating at 850 R. P. M. at 125 volts may produce say 142 k. w. Each of the

pump motors

28, 28 may-be rated at say 276 H. P. at 850 R. P. M., noting that adequate pumping capacity may be obtained by using either one of the pumping units; however, from the above data it is apparent that there is adequate generator capacity for the other pumping unit to be operated at the same time with reduced output for mixing mud", if desired. It will be obvious of course that with the machines in the cited example, the power produced and consumed may be widely varied by adjustment of the rheostats 81, 88 and. 81, 58.

If the operator should for any reason, while the system is operating with the set-up of Fig. 5

hereinbefore described, attempt to use the hoist drum 81 by throwing the clutch 88 into enaosaeoo deenergizing contactor 88 and consequently deenergizing the field circuits of the generators 8 and 8, to which the motor 88 is at that time connected.

If it is desired to drill and pump at half speed. 5 the set-up of Fig. 6 may be secured as follows: The mechanical set-up in connection with Fig. 8 may be the same as in connection with Fig. 8. The switches 8| and 82 are both thrown to their upper positions, and the

switches

28 and 2| are 10 likewise both thrown to their upper positions. The master switch C remains in its right hand position as described in connection with the setup of Fig. 5. By operation of the rheostat 88 the motor 88 may now be fed from generator 815 through contactors l4 and I8 while either of the

motors

28, 28 may be fed from generator 2. The voltage of generator 2 may of course be controlled by rheostat 81. For this set-up the engine preferably has its governor set for a lower speed as in case of the half speed hoisting set-up of Fig. 4. The pump motor 28 may now operate with a rating of say 137 H. P. at 425 R. P. M. since it is fed from one generator at 125 volts. The drill operating motor 88 may produce say H. P. at 355 R. P. M. being also fed at say 125 volts from generator 8.

It sometimes occurs that it is desirable to hoist and pump at the same time. For this purpose the fishing set-up, as shown in Fig. 7, may be 0 obtained. with this set-up hoisting operations may be performed as in case a drill rod should break, and at the same time one of the pumps may be used. This fishing setup may be secured with a pump motor fed from generator 2 and the motor 88 fed from generator 8 or vice versa. The operations for securing the set-up shown in Fig. 7 will first be described. The clutch 88 is thrown in and if it is desired to hoist only, the clutch II is thrown out. The switches "40 and 82 are both thrown to their lower positions. The

switches

28 and 2| are both thrown to their upper positions. The master switch C is thrown to its left hand position thereby causing closure of contactors I 8 and I8. The switch 88 is closed-i5 by hand, in the illustrative embodiment, to thereby connect the bus 28 to the blade 2|. -It will be noted that with the master switch in its left handposition the bypassing of contactor 28 is necessary since in that position of the master so switch the coil of contactor24 is not energized. The switch 21 for pump motor 28 is closed and the rheostats 81 and 88 operated either separately or in unison as desired. For this set-up the engines I and 4 may have their governors to set to causeoperation of the engines at substantially 1200 R. P. M., for example. The pump motor 28 may then operate at say 590 R. P. M. with a rating of 192 H. P., being fed from the generator 2 operating with a rating of 200 k. w. at 1200 R. P. M. The motor 88 operates at a rating of say 200 H. P. at 500 R. P. M. from the generator 8 operating at a rating of 200 k. w. at 1200 R. P. M.

If for any reason it is desired to operate the motor 88 from generator 2 and a pump motor from generator 5, the switches 8| and 82 are both thrown to their upper positions and the

switches

28 and 2| are both thrown to. their lower positions. The master switch remains in its left hand position and the remaining operations are similar to those described in connection with Fig.

If for any reason it is desirable to rotate the gagement, the contact 1| will be opened thereby drill as it is being hoisted, or lowered. with for example the fishing set-up of Fig. '1, the clutch 8| may be thrown into engagement.

In general, it will be apparent that current will not be supplied to either of

motors

26, 28 unwhich is true irrespective of the position of the master switch C. When the rheostats 51, 58 only for the

smaller generators

3, 6 are on field current can be obtained for the motor 38 only if the master switch C is in its right hand position, which is the position for the normal drilling operation. When the rheostats 31, 38 only are om-current can be obtained for the field windings of the pump motors provided the switches for these motors are respectively closed, and current can be obtained for. the field winding of motor 38 provided the master switch C is in its left hand position which is the hoisting position.

It will be obvious that if desired, particularly in connection with the set-ups. of Figs. 4, 6 and '1,- the rheostat for generator 2 may be operated separately from the rheostat for generator by simply disengaging the coupling III, and particularly in the case of Fig. 6 the rheostat for generator 3 may be operated separately from that for generator 6 by disengaging the coupling 2.

It will be evident from the description of the various set-ups that if desired only one engine and one set of generators need be used, if desired, for the first few thousand feet of drilling (the set being say as in Fig. 6) and that subsequently, or at any desired time, more than one engine and set of generators may be used for drilling (the set-up being say as in Fig. 5). It is of course obvious that the same applies at any stage of the drilling since if one engine fails, operations may be carried on with the other engine but with the driving motors operating at half speed. Full torque is however available whether the motors are running .at full speed or half speed.

Moreover to secure this full torque under either i condition of operation it is unnecessary to alter the driving or gear ratio as between the driving motors and the mednanical drill rigging.

What has been stated above also applies with regard to the fullspeed and half speed hoisting set-ups of Figs. 3 .and 4 respectively.

The exciter 33 being separately driven by an auxiliary engine (not shown) makes possible the use of said exciter for various purposes, such as for lighting the drill site, without necessity of having the main engines I, 4, running, or even before said main engines are available at all as while the drilling rig .and drive are being erected. Referring now to Figure 8 of the drawings a prime mover I is arranged to drive a pair of

generators

2 and 3 which are diagrammatically indicated as of equal capacity. Another prime mover 4 is arranged to drive .a pair of generators 5 and 6 which are diagrammatically indicated as of equal capacity. Generators 2 and 5 are permanently connected in series noting that the outer terminals of these generators .are connected to conductors I20 and I22 and that the intermediate terminals are connected to commonconductor I2I.

Generators

3 and 6 are permanently connected in series noting that the outer terminals of these generators are connected to conductors I23 and I24 and that the intermediate terminals are connected to common conductor I2I. Generators 2 and 5 are provided with series difKeren-Y tial field windings H3 and H4, self excited field windings I48 and HI and separately excited fiel windings H and 44, respectively. Generator and 6 are provided with differential seriesfiel windings I42 and I43, self excited field winding I44 and I45, and separately

excited field windings

64 and 6|, respectively. The separately excited field windings and the self excited field windings are normally cumulative. ing of each generator is so proportional that its ampere turns are always less than the air-gap ampere turns, that is, the resistance of this winding is such that theplotted curve (current in self excited winding as abscissa and terminal voltage as ordinate) never intersects the voltage characteristic curve of the generator. The polarity and magnitude of generator voltages are therefore determined by the separately excited windings. The main purpose of the self excited and the series differential field windings is to accentua'te the drooping characteristic of the generators so as to prevent the stalling of a prime mover in event one prime mover is temporarily unable to develop as much torque as the other 25 prime mover. That is, stalling of an imperfectly operating prime mover is prevented by the automaticweakening of the self excited field windings of the generators connected thereto upon occurrence of the reduction in speed of the faulty prime mover. Electromagnetic oontactors I and I36 are provided to connect series connected generators 2 and 5 in parallel with series connected

generators

3 and 6.

Pump motors

26 and 28 may be selectively connected to load conductors. 23--25 by means of

switches

21 and 29. An electromagnetic contactor 24 is operable to connect load conductor 25 with the blade of switch 2 I, noting that load conductor 23 is permanently connected to the blade .of switch 28 through the coil of overload relay 22.

By means of hand operated switches 28 and 2| the

load conductors

23 and 25 may be selectively connected either to conductors I8 and I2 I or conductors- I9 and I2I, or to conductors I8 and I8, as hereinbefore described in connection with Figure 1.

The drilling or hoisting motor 38 may be selectively connected to conductors I25 and I, or

I26 and I2], or to conductors I25 and I26 by means of hand operated switches 3| and 32 in substantially the same manner as described in connection with Figure 1.

Separately excited field windings 4|, 44, 64 and 6| are controlled by

rheostats

31, 38, 58 and 51 respectively. These rheostats .are, all energized from bus 3435 through conductors I50 and I5I when overload relays 22 and 69 are in their normally closed positions. An overload on either motor 38 or the pumping

motor

26 or 28 will cause the

respective overload relay

69 or 22 to ope ate to deenergize all of the separately excited generator field windings. Rheostats 31 and 38 are mechanically connected together by clutch III and rheostats 51 and 58 are mechanically connected together by clutch I I2 in the same manner as described in connection with Figure 1. An additional clutch I52 is arranged between rheostats 38 and 51 so that all four rheostats may be simultaneously operated or, if clutches ,I II and I '2 are disconnected, so that rheostats 38 and 51 may be operated simultaneously. An additional clutch I53 is arranged between rheostats 31 and 58, so that with clutches I I I and I I2 disconnected, rheostats 31 and 58 may be simultaneously oper- The self excited windlo ated. The utility of this arrangement will be better understood in connection with the description of the operation of the generators durin certain operations. a

Master controller C is a double pole, double throw switch having blades I6I and I62. When these blades are thrown to their left hand position a circuit is established from bus 65 I66, through conductor I61 to bus 64.

conductor 60, switch blade I62, conductor I64,-

operating coil or contactor I66, and through conductor I61 to bus 64. The closure of contactors I65 and I66 connect the generators in seriesparallel. When the blades of the master controller C are moved to their right hand position a control circuit is established from bus 65 through conductor I60, conductor 66, switch blades I6I, conductors 19, the operating coil of contactor 24 to bus 34 thereby causing contactor 24 to close. Another circuit is also established from bus 35 through conductor I60,'conductor 60, switch blade I62, conductor I34, operating coil of contactor The closure of contactors I66 and 24 connects

generators

2, 5 and 6, 6 to motor 25 (or 26) and motor I0 respectively.

Inasmuch as

motors

26, 26 and 60 are used in close proximity to explosive gases it is necessary that these motors be totally enclosed and for this reason each of these motors is provided with a .iorced draft ventilating system. For example,

motor 26 is provided with a blower motor I55 which is connected across the field winding 54 and field control rheostat I 56. Pump motor 26 is provided with a blower motor I51 which is connected across field winding 5I and field control rheostat I56. Motor 60 is provided with a blower motor I56 which is connected across field winding I0. It is to be noted that by connecting these ventilating motors across the respective field windings of the motors to be cooled that considerable saving is obtained in the number of conductors necessary.

All or the generators of this system of Fig. 8 being 01' ample capacity, as distinguished from the system of Fig. l, where the

generators

6, 6

are of reduced capacity as compared with the generators 2, 5, the same necessity is not present for provisions, such as the switch 'II, actuated with the hoist clutch 66, for preventing operation of the motor 66 for hoist-driving purposes when supplied from any particular generator or generators.

The operation of the system will be best understood by a consideration of the various mechanical set-ups and electrical circuits that may be secured with the system hereinbeiore described.

If it is desired to hoist the drill rod 66 or any other part attached to the hoisting cable I66, at full speed, the field rheostats should be moved to such a position that the clutches I I I, I I2 and I52 may be moved to their engaging positions. With the rheostats all simultaneously operable the voltages of the generators will be substantially equal which is a prerequisite to the operation of these generators in parallel. The switch 6I is moved to its upper position and the switch 62 is moved to its lower position thereby connecting motor 66 to conductors I25 and I26. The master controller C may then be moved to its left hand position thereby connecting

generators

2, 6. 5 and 6 in series-parallel as schematically shown in Figure 9. The field rheostats 61, 66, 51 and 56, are then moved in one direction or the other from their neutral position to simultaneously raise the voltage or all generators and thereby cause motor 5 60 to start and run in one direction or the other.

With the hoisting set-up shown in Figure 9 above described the motor 66 may be of 400 H. P. rating operating at 1,000 B. P. M. at 350 volts with a peak load capacity of 600 H. P. noting that since 10 each generator may, for example, be of k. w. rating that 600 k. w. will be available for hoisting. The ratings 01 the generators and motors are merely cited to more clearly set forth the utility oi the invention and are not intended to be taken 15 in a limiting sense.

It a break down occurs on one of the prime .mover units hoisting at halt speed may be obtained by connecting motor 66 to the parallel connected generators of the remaining unit by 20 means of switches 6| and 62 as schematically shown in Figure 10, noting that with this connection 300 k. w. of generatingcapacity will be available for operating motor 66 at about hall speed. 25 If it is desired to rotate the drill 66 and pump liquid down through the drill at the same time, the clutch 66 of Figure 2 is disengaged and the clutch 9| is engaged so as to connect. the driving shaft 66 to the shaft 66 for rotating the drill. 30 The switch 6| is moved to its upper position and the switch 62 is moved to its low position. I! it is desired to use both pumps I6 and I66, both

switches

21 and 26 are closed thereby connecting

motors

26 and 26 to the

load conductors

26 and 35 25, it is to be noted, however, that adequate pumping capacity may be obtained by using either one 01 the pumping units; however, in some instances it is desirable to operate the other pumping unit at reduced output to mix the liquid which is 40 Pumped into the casing 01 the well.

Switches

26 and 2| are also moved to their upper and lower positions respectively to connect generators 2 and 5 to one or both of the

pumping motors

26 and 26.

The master switch 0 is moved to its right hand 45 position, thereby energizing the operating coils of contactors I66 and 24, noting that, since contactor I65 is not energized in this position, generators 2 and 5 will not be connected in parallel with

generators

6 and 6. The circuit connections for 50 obtaining the above described set-up are schematically shown in Figure 11. Inasmuch as generators 2 and 5 are not electrically connected with

generators

6 and 6 it is desirable that

field rheostats

61 and 66 be connected together by means 55 or clutches III and that rheostats 51 and 56 be connected together by clutches II2, noting that for this set-up the clutches I52 and I56 should be disengaged so that the above, described pairs 01' rheostats may be independently operable to w vary the speed of the pumping motors or the speed of the drilling motor 66 independently.

It will be evident that with the set-up of Figure 11 the motor 66 may be operated at full speed for the drilling operation (which usually requires 55 3 and 6, namely, 300 k. w. may be used to energize motor 30-for drilling operations, yet such is rare- 1y necessary. It will be obvious that the power output of the generators in the above example may be widely varied to meet the requirements of the conditions by adjustment of the

rheostats

31, 38 and 51, 58.

If a breakdown occurs on one of the prime mover units, the drilling and pumping operations may be continued at half speed using the other prime mover unit as shown in Figure 12. The position of the clutches 9| and 98 will be the same as described in connection with Figure 11. Switches 3| and 32 are moved to connect motor 30 across the operative generator, whether it be 3 or 6, by means of switches 3| and 32. Likewise switches 20 and 2| are moved to connect the pump motor or pump motors across the generator which remains operative, whether it be 2 or 5. The master switch remains in its right hand position as described in connection with the set-up of Figure 5. All-of the rheostat clutches (III, II2, I52 and I53) are moved to disengaged position so that only the rheostats associated with the operative generators may be moved from their neutral positions to separately control the voltage of the respective generators. It will thus be seen that 150 k. w. will be available for pumping and that 150 k. w. will be also available for drilling at slightly less than full speed by weakening. the field of motor 30 by means of normally shunted resistor I60.

It sometimes occurs that it is desirable to hoist and pump at the same time, noting that this condition is generally known as the fishing set-up. Referring now to Figure 13, with this set-up hoisting operations may be performed as in case a drill rod should break, and at the 'same time one of the pumps may be used. This fishing set-up may be secured with a pump motor fed from

generators

2 and 3 in parallel and the motor 30 fed from generators 5 and 6 in parallel or vice versa. Obviously, the fishing operation may be conducted with the set-up shown in Fig. 11 if desired. The operations for securing the set-ups shown in Fig. 13 will first be described. The clutch 98 is engaged, and if it is desired to hoist only, the clutch 9| is disengaged. The switches 3| and 32 are both moved to their lower position and.v switches 20 and 2| are both moved to their upper positions. The master switch is moved to its left hand position thereby causing closure of contactors I and I36. If it is desired to operate either one or both-of

pump motors

26 and 28 it is necessary to manually close switch 85 and one or both of

switches

21 or 29. If for any reason it is desirable to rotate the drill as it is being hoisted or lowered with, for example, the fishing set-up of Figure 13, the clutch 9| may be moved into engagement.

It is thus seen that Figure 8 is in general similar to Figure 1, however, in order to simplify Figure 8 a. number of the interlocking features described in connection with Figure 1 have been omitted for the sake of clearness, however, it is to be understood that these features may also be used in connection with the system disclosed in connection with Figure 8 if desired.

It should be understood that it is not desired .to limit the invention to the exact details of construction shown and described for obvious modifications mayoccur to persons skilled in the art.

It is claimed and desiredto secure by Letters H Patent:

1. In an oil well drilling rig of the type having means for hoisting selected parts of the rig and means for operating the drill, two pairs of electric generators, the units of the respective pairs being of different capacity, a pair of prime movers for driving said pairs of generators respectively, 5 an electric motor, means for connecting said generators of larger capacity in series to said motor and for causing the latter to effect the hoisting operation at a speed independent of the speed of operation of said prime movers, and means for 1 connecting said generators of smaller capacity in series to said motor and for causing the latter to effect the drilling operation at a speed independent of the speed of operation of said prime movers. l6

2. In an oil well drilling rig of the type having means for operating the drill, including a hollow drill rod and a pump for supplying water to said drill rod, a pair of electric generators of different capacities, a prime mover for driving said go generators, an electric motor for driving said pump, an electric motor for driving said drill, a second pair of electric generators of substantially the same capacities as the generators of said first pair, respectively, a prime mover for 25 driving said second pair of generators, a source of separate field excitation for said generators, means for connecting said pump motor to either or both of the generators of larger capacity and for causing operation of said pump motor at a.80 speed independent of the speed of operation of said prime movers, and means for connecting the drill driving motor to either or both of the generators of smaller capacity and for causing operation of said drill driving motor at a speed in- 35 dependent of the speed of operation of said prime movers.

3. In an oil well drilling rig of the type having means for operating the drill including a hollow drill rod and a pump for supplying water to said drill rod, two pairs of electric generators, the units of the respective pairs being of difierent capacity, a pair 'ofv prime movers for driving said pairs of generators respectively, an electric motor for driving said pump, an electric motor for driving said drill, means for connecting said generators of larger capacity in series to said pump motor, means for connecting said generators of smaller capacity in series to said drill driving motor, and means for causing said pump and drill 5 driving motors to operate at a variable speed independent of the speedof operation of said prime movers.

4. A well drilling rig comprising means for hoisting selected parts of the rig, means for drill- Q ing, an electric motor, mechanism operable to selectively connect said electric motor either with said hoisting means or with said drilling means.

a pair of electric generators. of different capacities, prime mover means arranged to drive said generators, and means for connecting said motor to the generator of larger capacity when said hoisting means is operable and to the generator of smaller capacity when said drilling means is operable, and for permitting variation of the speed of said motor in its hoist and drill driving operations independently of the speed of operation of said prime mover means.-

5. A well drilling rig comprising means for hoisting selected parts of the rig, drilling means, an electric motor, mechanism operable to opera tively connect said motor selectively to said hoisting means or to said drilling means, a pair of D. C. generators of predetermined capacity, a

pair of D. C. generators of smaller capacity, a

pair of independent prime movers, each oi said prime movers arr nged to drive a generator 01' predetermined capacity and a generator of smaller capacity, and switching means for connecting said generators of predetermined capacity in series to said motor when said motor is operatively connected to said hoisting means and for connecting said generators of smaller capacity in series to said motor and insuring eflective operation of said latter motor supplied by the generators of smaller capacity only when said latter motor is out of driving relation to said hoisting means.

6. A well drilling rig comprising means for hoisting selected parts of the rig, drill rod rotating means, an electric motor, mechanism operable to selectively connect said motor in driving relation either with said hoisting means or said drill rotating means or with both of said means, a pair of electric generators of predetermined capacity, a pair of electric generators of smaller capacity,

prime movers arranged to drive said generators,

switching means selectively operable to connect said motor across one or both of said generators of predetermined capacity or across one or both of said generators of smaller capacity. and means for rendering said motor effective for driving purposes when supplied by one or both of said generators of smaller capacity only in case said hoisting means is disconnected from said motor.

7. A well drilling rig comprising a drill, means for hoisting selected parts of the rig, means for rotating the drill, an electric motor, means for drivingly connecting said motor to said hoisting means or said drill rotating means, a pump arranged to circulate liquid, a second electric motor for driving said pump, a plurality of electric generators, a plurality of prime movers, an independently driven source of separate excitation for said generators, means operable to connect one of said generators to supply energy to said first mentioned motor and to connect another of said generators to supply energy to said second mentioned motor, and operating connections for insuring selectively that one prime mover may drive one of said generators to supply energy to one or said motors and another of said prime movers may drive another of said generators to supply energy to another of said motors, or that one engine may simultaneously drive one generator to supply said hoisting and drilling motor and another generator to supply said pump motor, and means operative to control the energy supplied by said generators to said motors to insure operation of said motors at speeds independent 01 the speed of operation of said prime movers.

8. A well drilling rig comprising a drill, means for rotating and hoisting the drill, an electric motor, means for drivingly connecting said motor to said drill actuating means, a pump arranged to circulate liquid, a second electric motor for driving said pump, a plurality of electric generators, a plurality of prime movers, means operable to connect one oi. said generators in energysupplying relation tosaid drill-actuating motor and to connect another of said generators in energy-supplying relation to said pump motor, and operating connections for insuring selectively that one prime mover may drive one of said generators to supply energy to said drill-actuating motor and another 0! said prime movers may drive another of said generators to supply energy to said pump motor, or that either engine may simultaneously drive one generator to supply. said drill-actuating motor and another generator to supply said pump motor, and means operative to control the energy supplied by said generators to said motors to insure operation of said motors at speeds independent oi the speed of operation oi said prime movers. 5

9. A well drilling rig comprising means for hoisting selected parts of said rig, drilling means, a pump arranged to circulate liquid in the casing of said well, an electric motor arranged to drive said pump, a second electric motor, mechanism 10 operable to selectively connect said second motor in driving relation with said hoisting means or said drilling means or with both of said means, a pair of series connected electric generators, another pair of series connected electric general5 tors, two engines each serving as a common driving means for a generator of each of said pairs and means selectively operable to either connect both pairs of said generators in series-parallel to said second motor, for hoisting, or to connect 20 said first mentioned generators in series to said pump driving motor and to connect said another pair of generators in series to said second motor for drilling and to provide for the operation 01' either motor at diflerent speeds independent oi as the speed of operation of said engines.

10. A well drilling rig comprising means for hoisting selected parts of said rig, drilling means, a pump arranged to circulate liquid in the casing of said well, an electric motor arranged to drive 80 said pump, a second electric motor, mechanism operable to selectively connect said second motor in driving relation with said hoisting means or said drilling means or with both of said means, a pair of electric generators connectabie in series, 86 a second pair of electric generators connectable in series, a pair of internal combustion engines each arranged to drive one of said generators of each of said pairs, and means selectively operable either to connect said two pairs of genera 40 tors in series-parallel and to connect said second motor to the aforesaid series-parallel connected generators for hoisting or to connect said generators of one of said pairs in series to said pump I driving motor to circulate liquid in said casing and as I to connect said generators of the other of said pairs in series to said second motor for drilling and to render said motors operative at different speeds independent of the speed of operation of said engines.

11. A well drilling rig comprising means for hoisting selected parts of the rig, an electric motor arranged to drive said hoisting means, a pair oi. electric generators connectable in series, another pair of electric generators connectabie in series a pair'oi prime movers each arranged to drive one of said tirst mentioned generators and one 01' said last mentioned generators, and means selectively operable to-conneot both pairs of said generators in series parallel to said motor for 00 hoisting at full speed or to connect the generators driven by either one 01 said prime movers in parallel to said motor for hoisting at halt speed and to render said motor operative at diiierent speeds independent of the speed oi operation or as said prime movers.

12. A well drilling rig comprising a drill, means for hoisting and rotating said drill, an electric motor arranged to drive said hoisting and rotating means, a pair of electric generators connectable in first mentioned generators and one of said second mentioned generators, and means comprising selectively operable switches for connecting the generators driven by said engines in seriesparallel and to connect said motor to the aforesaid series-parallel connected generators for hoisting or for connecting either one or both of the generators of one of said pairs to said motor, and for rendering said motor operative at speeds independent of the speed of operation of said engines. I

13. A well drilling rig comprising means for hoisting selected parts of the rig, an electric motor arranged to drive .said hoisting means, a pump arranged to circulate liquid in the well, an electric motor arranged to drive said pump, each of said motors having a separately excited field winding, motor driven ventilating blowers arranged to circulate air through said hoisting and pumping motors, the motors of said blowers being connected across said separately excited field windings respectively, a pair of engine driven electric generators, and means operable to selectively connect said hoisting and pumping motors to said generators respectively and to render said motors operative at speeds independent of the speed of. operation of said engine driven generators.

14. A well drilling rig comprising means for hoisting selected parts of the rig, an electric motor arranged to drive said hoisting means, a pump arranged to circulate liquid in the well, an electric motor arranged to drive said pump, a pair of electric generators connectable in series, a second pair of electric generators connectable in series, each of said generators having a separately excited field winding and individual rheostats arranged to control the excitation of said windings, prime movers arranged to drive said generators, switching means operable to selectively connect said pairs of generators in seriesparallel to said first mentioned motor for hoisting or to connect two of said generators in parallel to said hoisting motor and the other two of said generators in parallel to said pumping motor for circulating liquid in said well, and means for either connecting all of said rheostats together so as to be operable simultaneously while said switching means connect all said generators in series-parallel for hoisting or connecting said rheostats in pairs so that each pair is operable simultaneously and independently while said switching means connect two of said generators in parallel to said hoisting motor and connect the other two of said generators in parallel to said pumping motor sa d motors being operative at speeds independent of the speed of operation of said prime movers through suitable adjustment of said individual rheostats.

15. A well drilling rig comprising means for hoisting selected parts of the rig, means for drilling, an electric motor, mechanism operable to selectively connect said motor either with said hoisting means or said drilling means, a pair of electric generators of different capacities, prime mover means arranged to drive said generators, and means for connecting said motor to the generator of larger capacity when said hoisting means is operable and to the generator of smaller capacity when said drilling means is operable, said generator of smaller capacity being operative to cause said motor to effectively drive said drilling means only when said motor is disconnected fromsaid hoisting means.

16. In a well drilling rig oi the type having means for imparting linear movement to selected parts of the rig and means for imparting rotative movement to one of saidparts, two pairs of. electric generators, a pair of prime movers for driving said pairs of generators respectively, an 5 electric motor, means for connecting a generator of each of said pairs in series to said motor and rendering said motor operative to efiect said linear movement, means for connecting the other generator of each of said pairs in series to said 10 motor and rendering said motor operative to effect said rotative movement, and means for providing that said motor when operative to eiiect said linear and rotative movements may operate at diiferent speeds independent of the speed of 1:; operation of said prime movers.

1'7. In a well drilling rig, an operating element capable of. both rotative and linear movements,

a pair of electric generators of different capacities, a prime mover for driving said generators, a 20 second pair of electric generators of different capacities, a prime mover for driving said second pair of generators, an electric motor operable selectively to impart rotative or linear movement to said element, means for connecting said motor to one or both of said generators of larger capacity and renderinglsaid motor operative at a speed independent of the speed of the prime mover or prime movers driving the generator or generators supplying said motor to effect linear movement of said element, means for connecting said motor to one or both of said generators offsmaller capacity and rendering said motor operative at a speed independent of. the prime mover or prime movers driving said generator or generators supplying-'35 said motor to effect rotative movement of said element, and means for preventing efi'ective operation of said motor supplied from said generators of smaller capacity when said motor is connected to impart reciprocating movement to 4 said element.

18. A well drilling rig comprising a drill, means for operating said drill to impart linear and rotative movements thereto, a pump for supplying liquid to said drill, a plurality of prime movers, means for converting the power of said prime movers and utilizing the converted power for driving said drill-actuating, means and said pump, said converting means comprising a plurality or separately excited electrical generators arranged to be driven by said prime movers, an independently driven source of separate excitation for said generators, an electrical motor arranged to drivesaid drill-actuating means, an electrical motor arranged to drive said pump, and means for providing for the operation of said drill-actuating motor through energy supplied by a plurality of said generators driven by one or more of said prime movers or the operation 01 each of said motors through energy supplied by an individual generator while both said generators are driven by either one of said prime movers, and for varying the speed of operation of each said motor independent of the speed of the other said motor and the speed of the prime mover or prime movers driving the generator or generators supplying energy to said motor.

19. A power plant for drill rigs of the type including a drilling element adapted to be rotated and hoisted, comprising a plurality of engines, electro-mechanical means for converting the power of said engines and utilizing the converted power for driving said-drilling means, said. converting means comprising a pair of electrical generators arranged in driven relation to. each generators connected in supply relation to said motor.

20. A well drilling rig comprising a drill, means for hoisting and rotating said drill, an electric motor arranged to drive said hoisting and rotating means, a pump arranged to supply liquid to said drill, an electric motor arranged to drive said pump, a pair of electric generators connectable in series, another pair of electric generators connectable in series, a pair of independent internal combustion engines each arranged to drive one of said first mentioned pair of generators and one of said second mentioned pair of generators, and means comprising selectively operable switches for connecting the generators driven by said engines in series-parallel and to connect said hoist driving motor to the aforesaid seriesparallel connected generators for hoisting or for connecting either generator of one of said pairs of generators to said drill driving motor and either generator of the other pair of generators to said pump motor to thereby insure operation of both of said motors supplied by the generators driven by either engine, and means for render-' ing said motors operative at difl'erent speeds independent of the speed of operation of said engines.

21. In an oil well drilling rig of the type having means for operating the drill including a hollow drill rod and a pump for supplying water to said drill rod, a pair of electric generators of diflerent capacities, means for driving said generators, an independently driven source of separate field excitation for said generators, an electric motor for driving said pump, an electric motor for actuating said drill, means for connecting said pump motor to the generator of larger capacity and for connecting the drill motor to the generator of smaller capacity and for providing for operation of each of said motors at different speeds independent of the speed of operation of the other motor and of the generator driving means.

22. A well drilling rig comprising a drill rod, means for actuating said drill rod to efiect hoisting and rotation thereof, an electric motor for actuating said latter means, a pump arranged to circulate liquid in the well, a second electric motor arranged to drive said pump, a pair of electric generators, a prime mover arranged to drive both of said generators, an independently driven source of separate excitation for said generators, and means for connecting one of said generators to said drill-actuating motor and the other generator to said pump motor and for providing for operation of each of said motors at difierent speeds independent of the speed 01' the other motor and said generator driving means through variation of the field excitation of the generators driving the several motors.

NATHAN WILKINSON.