US2785362A - Adjustable voltage drive - Google Patents

Adjustable voltage drive Download PDF

Info

Publication number
US2785362A
US2785362A US245372A US24537251A US2785362A US 2785362 A US2785362 A US 2785362A US 245372 A US245372 A US 245372A US 24537251 A US24537251 A US 24537251A US 2785362 A US2785362 A US 2785362A
Authority
US
United States
Prior art keywords
generator
motor
field winding
series
winding
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US245372A
Other languages
English (en)
Inventor
William R Harding
Schaelchlin Walter
Gerald E Mathias
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Westinghouse Electric Corp
Original Assignee
Westinghouse Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to CA551402A priority Critical patent/CA551402A/fr
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US245372A priority patent/US2785362A/en
Application granted granted Critical
Publication of US2785362A publication Critical patent/US2785362A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P7/00—Arrangements for regulating or controlling the speed or torque of electric DC motors
    • H02P7/06—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual DC dynamo-electric motor by varying field or armature current
    • H02P7/18—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual DC dynamo-electric motor by varying field or armature current by master control with auxiliary power
    • H02P7/34—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual DC dynamo-electric motor by varying field or armature current by master control with auxiliary power using Ward-Leonard arrangements

Definitions

  • Our invention relates to electric systems of control for driving an electric motor in either of two directions, and more specifically, our invention is directed to a variable voltage drive for a direct current motor coupled to drive a hoist, or similar load, and which systems provide highly desirable operating characteristics both for the hoisting of loads and for the lowering of loads.
  • One broad object of our invention is the provision of a drooping speed torque characteristic for both the driving operation of a motor and the overhauling operation of the motor.
  • a more specific object of our invention is the provision of a control, in a Ward-Leonard type of drive, for obtaining greater and greater decrease in speed of the motor with a rise in load on the motor with the selection of greater base speeds of operation of the motor.
  • Another somewhat specific object of our invention is the provision of a control, in a Ward-Leonard type drive, for obtaining, on a slow selected speed of the motor, a substantially constant speed regardless of the magnitude of the load from no-load to somewhat more than full-load.
  • Another somewhat specific object of our invention is the provision of a control, in a Ward-Leonard type of drive, for obtaining automatic operation of the generator as a difierentially compound machine and the motor as a cumulatively compound machine when the voltage of the generator has one polarity and for obtaining non-compounding operation of the generator and motor when the voltage of the generator has opposite polarity, all without the use of elaborate switching means.
  • Figure 1 is a diagrammatic showing of a preferred embodiment of our invention as applied to hoist equipment
  • Fig. 2 shows the speed-load characteristics we obtain with our system of control for both the hoisting operation of a load and lowering operation of an overhauling load
  • Figs. 3 and 4 are so-called straight-line diagrams of our invention illustrating two modifications thereof.
  • variable voltage control system includes a main generator G and an exciter E coupled to be driven by the constant speed induction motor IM disposed to be connected by means of the circuit breaker CB to the alternating current supply buses shown.
  • the main generator G has its armature connected in a loop circuit with the armature of the motor M.
  • the generator G has a main field winding GF, a suicide wind ing 43 and a series field winding GSF.
  • the motor M has a main field winding MF and a motor series field winding MSF.
  • a rectifier 31 is connected in series with the motor series field winding to provide for a unidirectional energization of this field winding.
  • a master switch, or controller, MS is disposed to control the sequence of operation for both the hoisting operation of the hoist H mechanically coupled to the motor M, and the lowering of both non-overhauling and overhauling loads secured to the hoist cable.
  • the exciter E is provided with the exciter field EF and its adjustable rheostat RE and provides, when operated at normal speed, a constant potential source of direct current.
  • the attendant must first close the emergency stop switch ES, whereupon a circuit is established from the positive armature terminal of the exciter through contact 1 of switch ES, conductor 2, controller segment 3, conductor 4, auxiliary switch 5 on the circuit breaker CB, contact 6 of the switch ES, actuating coil 7 of the low voltage relay LV, back contacts 8 of the overload relay OL, conductor 9 and contact 10 of the switch ES and the series field 11 of the exciter E to the negative terminal of the exciter.
  • the emergency stop switch is normally located in the housing of the master switch MS and is provided with a small lever, not shown, projecting from the master switch housing at the side thereof. Such disposition of the actuating lever makes quick operation of the switch ES possible when the need arises.
  • Operation of the low voltage relay LV causes the closing of contacts 12 which are in parallel with the controller segment 3, and thus thereafter make the operation of the low voltage relay independent of the position of the master switch or controller MS.
  • the operation of low voltage relay LV also closes contacts 13 to thus connect the conductor 14 to the positive terminal of the exciter E.
  • Movement of the controller to the first hoist position also establishes a circuit through the actuating coil 21 of the kill-flux relay KF to thus open the circuit for the suicide field 43 at the contacts 22.
  • an energizing circuit is established from the positive terminal of the generator G through the actuating coil 27 of the load relay LR, the actuating coil 23 of the overload relay L, contacts 29 of the control relay 3!), rectifier 31, the motor series field MSF, and the motor armature to the negative terminal of the generator G.
  • the motor field MP Since the motor field MP is fully energized and at the start the starting current is apt to be quite heavy, it is apparent that the motor series field MSF is heavily energized. The motor M thus develops a relatively large starting torque.
  • the generator field G? is energized with all the resistor sections of the generator field rheostat in its circuit, and the generator series field GSF is by-passed by contacts 29 of relay 3% on th first point hoisting, the voltage developed by the generator is relatively low and in consequence, the load is picked up very softly and the starting is elfected with the minimum of shock on the mechanical system.
  • the speed load curve Hi represents the operating characteristic on the first point hoist, and it will be noted that the speed is quite low, particularly if the load is heavy, and that the speed is somewhat higher if the load is nearer the no-load value. From an operating standpoint, this is a very desirable feature since the shocl: on the mechanical system of a rapid start would be much greater if the load were heavy and the starting effected very rapidly.
  • control relay 3% has a second back contact 32 for shunting a portion of the resistor 33 disposed in shunt relation to the motor series field MSF.
  • control of the motor series field may be modified to suit the requirements of the load characteristics that may be encountered in practice.
  • the controller If the controller be moved to the second hoist position, the resistor section 38 in the generator field circuit is shunted by contact segment 37, to thus increase the generator field excitation.
  • a circuit is also established from the positive conductor 14 through the controller segmentlld, conductor 35, actuating coil 36 of the control relay 30 to the negative conductor Operation of the control relay it opens the contacts 29 and 32 to thus increase the efiect of the motor series field and modify the voltage characteristics of the generator G by the insertion of the generator series field GSF in the load circuit including the motor and generator.
  • the winding'arrangement of the generator series fi ld is such that its effect is differential with respect to the main field GP to thus decrease the voltage of the generator with a rise in load. This provides a speed load characteristic as shown by H2. It will be noted that the acceleration of the load, it there is a heavy load, is still relatively low, but that the speed rise becomes greater and greater with a decrease in load on the hoist.
  • the timing arrangement of the brake relay BR is such that for most stopping operations, the dynamic braking circuit through the suicide field 43 is established for a suificient period of time to bring the motor M substantially to rest before the contacts 20 open to set the brake B. This is of considerable advantage because substantially noslippage is encountered in the brake shoes, and thus long and reliable brake life is assured by our control arrangement.
  • controller segment 46 establishes a circuit for the brake relay and for the killfiux relay KF exactly in the same manner that the con troller segment 15 functions for the hoist operation.
  • a circuit is also established from the positive conductor 14- through controller segment 59, conductor 25, generator field GP, and conductor 24, resistor 5i, controller segment 52, and all of the resistor sections of the generator field rheostat GPR to the negative conductor.
  • Another circuit is established from the positive conductor 14 through the controller segment 47, magnetizing coil 48 of the time limit relay TL to the negative conductor 9.
  • the time limit relay TL operates to open the contacts 49 to thus insert the extra resistor section 51 in the circuit of the generator field GP to provide a relatively low excitation for the generator G.
  • Another circuit is established from the positive conductor 2 through the motor field MP, conductor 53, controller segment 54, and conductor to a selected point on the motor field rheostat MFR.
  • the controller segment 54 thus shunts a considerable portion of the motor field rheostat to thus heavily excite the motor field MF and provide for a heavy starting torque and slow motor speed.
  • the heavy motor excitation coupled with the low voltage of the generator G provides a speed load characteristic as evidenced by the curve L1 of Fig. 2. it will be noted that the curve Ll provides for a substantially constant motor speed from no-load to full load for the first controller position. 7
  • the controller segment 47 interrupts the circuit for the magnetizing coil 48 of, the time limit relay TL. If the motor load is sufiiciently low, the load relay LR drops out and in consequence, contacts 58 are opened. This means that the holding coil 57 of the time limit relay TL is deenergized and the result is that contacts 49 close on the fifth position of the controller to materially increase the generator excitation. This has a considerable advantage because if the load is not sufiiciently low, contacts 58 remain closed, and contacts 49 remain open with the result that the generator field GF is not so heavily excited. The speed of the motor thus varies more and more with a change in load on the fifth position of the controller.
  • the load relay LR is of the non-fluttering type and works in conjunction with the time limit relay TL so that it will measure the actual motor load without the accelerating load component and the circuit is so arranged that the generator voltage will stay below a certain value whenever the load to be lowered exceeds a certain per centage, thereby maintaining safe lowering speeds at all times. Further, the arrangement is such that the load relay does not become efiective except on the last lowering position when the higher speeds might be encountered.
  • the stopping operation from the lowering operation will, of course, be substantially the same for the motor as when the controller is moved from the hoist position to the off position.
  • the closing of the suicide field circuit will again be delayed by the counterelectromotive force, and will effect dynamic braking on the motor M to bring it substantially to rest just a moment before the brake B sets.
  • Fig. 3 we have shown a somewhat modified circuit for the generator difierential series field and the motor series field, and by appropriate operation of the switches 64) and 61, the generator differential field may be utilized when the voltage of the generator is reversed, which is not the case when the embodiment shown in Fig. 1 is utilized. It will be noted that in the showing of Fig. 3, the rectifier is only in series with the motor field, and that a reverse excitation of the motor is not possible, and the transition from cumulative compound excitation of the motor for hoisting loads to non-compound excitation for lowering operation proceeds automatically in exactly the same manner as shown in Fig. 1.
  • Fig. 4 we have shown a still further arrangement of the generator series field winding, and the motor series field winding, and by a suitable selection of the constants for the resistor 62 shown and appropriate operation of the switch 63 shunting the series field of the generator, the novel operating characteristics obtained with the showing in Fig. 1 may be obtained. However, it is also possible in this arrangement to utilize the generator series field during the lowering operation.
  • a variable voltage control system for a direct current motor which may be coupled to drive a hoist, or other load, comprising, in combination, a generator and motor each having an armature winding, said motor being connected to the generator to be operated thereby, a series field winding and a separately excited field winding for each of said dynamoelectric machines, an external source of energization for said separately excited field windings,
  • field reversing switch means for the separately excited field winding of the generator, a rectifier in series with the series field winding of the motor, the winding sense of the series field winding of the generator being differential with respect to its separately excited field winding and the winding sense of the series field of the motor and the polarity sense of the rectifier being such that the motor is a cumulative compound motor when the excitation direction or" the separately excited field of the generator is such as to operate the motor in one selected direction.
  • a variable voltage control system for a direct current motor which may be coupled to drive a hoist, or similar other load, comprising, in combination, a generator and motor each having an armature winding, said motor being connected to the generator tobe operated thereby, a series field winding and a separately excited field winding for each of said dynamo-electric machines, said generator also having a third field winding and a dynamic braking resistor connected in series with said third field winding, an external source of energization for said separately excited field windings, field reversing switch means for the separately excited field winding of the generator, a rectifier in series with the series field winding of the motor, the winding sense of the series field winding of the generator being differential with respect to its separately excited field winding and the winding sense of the series field of the motor and the polarity sense of the rectifier being such that the motor is a cumulative compound motor when the excitation direction of the separately excited field of the generator is such as to operate the motor in one selected direction, and control means operable upon
  • a variable voltage control system for a direct current motor which may be coupled to drive a hoist, or similar other load, comprising, in combination, a generator and motor each having an armature winding, said motor being connected to said generator to be operated thereby, a series field winding and a separately excited field winding for each of said dynamo-electric machines, said generator also having a third field winding and a dynamic braking resistor connected in series with said third field winding, an external source of energization for said separately excited field windings, field reversing switch means for the separately excited field winding of the generator, a rectifier in series with the series field winding of the motor, the winding sense of the series field winding of the generator being difierential with respect to its separately excited field winding and the winding sense of the series field of the motor and the polarity sense of the rectifier being such that the motor is a cumulative compound motor when the excitation direction of the separately excited field of the generator is such as to operate the motor in one selected direction, control means oper
  • a variable voltage control system for a direct current motor comprising, in combination, a generator and motor each having an armature Winding, a series field winding, and a separately excited main field winding, 21 source of direct current potential for exciting the main field windings, control switch means operable in one di rection for separately exciting the main motor field winding at a given value and the generator main field winding in a given sense to effect operation of the motor in one direction, a rectifier, said motor and generator armature windings, the motor and generator series field windings and said rectifier being connected in a loop circuit, during operation of said motor in said one direction, the winding sense of the generator series field winding being diiferential to the generator main field winding and the rectifying sense and the winding sense of the motor main field winding being such that the motor is a cumulative compound motor.
  • a variable voltage control system for a direct current motor comprising, in combination, a generator and motor each having an armature winding, a series field winding, and a separately excited main field winding, a third field winding for the generator, a source of direct current 530 tcntial for exciting the main field windings, control switch means operable in one direction for separately exciting the main motor field winding at a given value and the generator main field winding in a given sense to effect operation of the motor in one direction, a rectifier, said motor and generator armature windings, the motor and generator series field windings and said rectifier being connected in a loop circuit, during operation of said motor in said one direction, the winding sense of the generator series field winding being differential to the generator main field winding and the rectifying sense and the winding sense of the motor main field Winding being such that the motor is a cumulative compound motor, and means for connectin the said third field winding to the motor armature terminals to effect dynamic braking of the motor and to kill the generator excitation
  • a variable voltage control system for a direct current motor comprising, in combination, a generator and motor each having an armature winding, a series field winding, and a separately excited main field winding, :1 source of direct current potential for exciting the main field windings, control switch means operable in one direction for separately exciting the main motor field winding at a given value and the generator main field winding in a given sense to effect operation of the motor in one direction and operable in an opposite direction for separately exciting the motor main field winding at a value higher than said given value and the generator main field winding in an opposite sense to efiect reverse operation, a rectifier, said motor and generator armature windings, the motor and generator series field windings and said rectifier being connected in a loop circuit, during operation of the motor in said one direction the winding sense of the generator series field winding being differential to the generator main field winding and the rectifying sense and the winding sense of the motor main field winding being such that the motor is a cumulative compound motor, and operable during reverse operation
  • a variable voltage control system for a direct current motor comprising, in combination, a generator and motor each having an armature winding, :1 series field winding, and a separately excited main field winding, a source of direct current potential for exciting the main field windings, control switch means operable in one direction for separately exciting the main motor field winding at a given value and the generator main field winding in a given sense to effect forward operation, a rec tifier, said motor and generator armature windings, the motor and generator series field windings, and said rec tifier being connected in a loop circuit, during forward operation the winding sense of the generator series field winding being differential to the generator main field winding and the rectifying sense and the winding sense of the motor main field winding being such that the motor is a cumulative compound motor, a shunting circuit for the series field windings of the generator and motor, and means for changing the impedance of the shunting circuit during forward operation.
  • a variable voltage control system for a direct current motor comprising, in combination, a generator and motor each having an armature winding, a series field winding, and a separately excited main field winding, a third field winding for the generator, 2. source of direct current potential for exciting the main field windings, control switch means operable in one direction for separately exciting the main motor field winding at a given value and the generator main field winding in a given sense to effect forward operation and operable in an opposite direction for separately exciting the motor main winding at a value higher than said given value and the generator main field winding in opposite sense to err-act reverse operation, a rectifier, said motor and genwindings and said rectifier being connected in a circuit, during forward operation the winding sense sense and the winding sense or" the motor main field winding being such that the motor is a cumulative compound motor, and operable during reverse o eraticn for disconnecting the series field windings from the loop circuit, and means for connecting the said third field winding to the motor armatureterminals
  • a variable voltage control system for a direct current motor comprising, in combination, a generator and motor each having an armature winding, a series field winding, and a separately excited main field winding, a third field winding for the generator, 2. source of direct current potential for exciting the main field windings, control switch means operable in one direction for separately exciting the main motor field winding at a given value and the generator main field winding in a given sense to effect forward operation, a rectifier, said motor and generator armature windings, the motor and generator series field windings and said ectifier being conected in a loop circuit, during forward operation the winding sense of the generator series field winding being differential to the generator main field winding and the rectifying sense and the winding sense of the motor main field winding being such that the motor is a cumulative compound motor, a shunting circuit for the series field windings of the generator and motor, and means for changing the impedance of the shunting circuit during forward operation, and means for connecting the said third field winding
  • a variable voltage control system for a direct current motor comprising, in combination, a generator and motor each having an armature winding, a series field winding, and a separately excited main field winding, a third field winding for the generator, 8. source of direct current potential for exciting the main field windings, control switch means operable in one direction for separately exciting the main motor field winding at a given value and the generator main field winding in a given sense to effect forward operation and operable in an opposite direction for separately exciting the motor main field winding at a value higher than said given value and the generator main field winding in an opposite sense to effect reverse operation, a rectifier, said motor and generator armature windings, the motor and generator series field windings said rectifier being connected in a loop circuit, during hoisting operation, the winding sense of the gW-erator series winding being differential to the gene ator main field winding and the rectifying sense and the winding sense of the motor nL'u field winding being such that the motor is a cumulative compound motor,
  • a variable voltage control system for a direct current motor which may he coupled to drive a hoist, or similar other load, comprising, in combination, a generator and motor each having an armature winding, said motor being connected to the generator to be driven thereby, a series field winding and a separately excited field winding for each of said dynamo-electric machines, said generator also having a third field winding and a dynamic braking resistor connected in series with said third field winding, an external source of energization for said separately excited field winding, field reversing switch means for the separately excited field of the generator, a rectifier in series with the series field winding of the motor, the winding sense of the series field winding of the generator being differential with respect to its separately excited field winding and the winding sense or" the series field of the motor and the polarity sense of the rectifier being such that the motor is a cumulative compound motor when the excitation direction of the separately excited field of the generator is such as to operate the motor in the hoist direction, control means, operable upon
  • a variable voltage control system for a direct current motor which may be coupled to drive a hoist, or similar other load, comprising, in combination, a genorator and motor each having an armature winding, said motor being connected to the generator to be driven thereby, a series field winding and a separately excited field Winding for each of said dynamo-electric machines, said generator also having a third field winding and a dynamic braking resistor connected in series with said third field winding, an external source of energization for said separately excited field windings, field reversing switch means for the separately excited field of the generator, a rectifier in series with the series field winding of the motor, the winding sense of the series field winding of the generator being difierential with respect to its separately excited field Winding and the windingsense of the series field winding of the motor and the polarity sense of the rectifier being such that the motor is a cumulative compound motor when the excitation direction of the separately excited field of the generator is such as to operate the motor in the hoist
  • a generator and motor having their armature windings connected in a loop circuit, a main field winding for the generator, a main field Winding for the motor, said loop circuit including the armature windings of the generator and motor, a generator series field winding, a shunting circuit including switching means for shunting the generator series field winding, :1 rectifier, a motor series field winding, and an adjustable impedance connectible in shunt relation to the generator series field winding, the rectifier, and the motor series field winding, and rheostatic control means for changing the magnitude of the exciting current of the generator field winding from.
  • a generator and motor having their armature windings connected in a loop circuit, a main field winding for the generator, a main field winding for the motor, a motor load-current responsive relay having an actuating coil, said loop circuit including the armature windings of the generator and motor, the actuating coil of said load-current responsive relay, a generator series field winding, a shunting circuit including switching means for shunting the generator series field winding, a rectifier, a motor series field winding, and an adjustable impedance connectible in shunt relation to the generator series field winding, the rectifier, and the motor series field winding, and rheostatic control means for changing the magnitude of the exciting current of the generator field winding from Zero over selected positive and nega tive ranges, means responsive to the operation of the load-current responsive relay for increasing the excitation of the generator main field winding beyond the ranges of the rheostatic control means.
  • a generator and motor having their armature windings connected in a loop circuit, a main field winding for the generator, 21 main field winding for the motor, said loop circuit including the armature windings of the generator and motor, a generator series field winding, 21 shunting circuit including switching means for shunting the generator series field winding, a rectifier, a motor series field winding, and an adjustable impedance connectible in shunt relation to the generator series field winding, the rectifier, and the motor series field Winding, rheostatic control means for changing the magnitude of the exciting current of the generator field winding from zero over selected positive and negative ranges, a third field winding for the generator, ant means responsive to a selected drop in the counter-electromotivc force of the motor, upon deenergization of the main field winding of the generator for connecting the third generator field winding across the generator armature terminals to thus provide a dynamic braking
  • a generator and motor having their armature windings connected in a loop circuit, a main field winding for the generator, a main field winding for the motor, a motor load-current responsive relay having an actuating coil, said loop circuit including the armature windings of the generator and motor, the actuating coil of said load-current responsive relay, a generator series field winding, 21 shunting circuit including switching means for shunting the generator series field winding, a rectifier, a motor series field winding, and an adjustable impedance connectible in shunt relation to the generator series field Winding, the rectifier, and the motor series field winding, rheostatic control means for changing the magnitude of the exciting current of the generator field winding from zero over selected positive and negative ranges, means responsive to the operation of the load-current responsive relay for increasing the excitation of the generator main field Winding beyond the ranges of the rheostatic control means, a third field winding
  • a system of control comprising in combination, a generator and motor having their armature windings connected in a loop circuit, a main field winding for the generator, a main field wind- 11 ing for the motor, a motor load responsive relay having an actuating coil, said loop circuit including the actuating coil of said load responsive relay, a generator series field winding having a winding sense that is differential to the generator main field winding, a shunting circuit for the generator series field windings including switching means for closing and opening the shunting circuit, a rectifier, a motor series field winding connected in series with the rectifier, and an adjustable resistor disposed to be connected in shunt relation to the generator series field winding, the rectifier, and the motor series field winding, the polarity sense of the rectifier being such that the motor series field winding acts cumulatively to the main motor field winding when the output voltage of the generator has a given polarity, rheostatic control means for changing the excitation
  • a system of control comprising in combination, a generator and motor having their armature windings connected in a loop circuit, a main field winding for the generator, a main field winding for the motor, a motor load responsive relay having an actuating cc-il, said loop circuit including the actuating coil of said load responsive relay, a generator series field winding having a winding sense that is differential to the generator main field winding, a shunting circuit for the generator series field windings including switching means for closing and opening the shunting circuit, a rectifier, a motor series field winding connected in series with the rectifier, and an adjustable resistor disposed to be connected in shunt relation to the generator series field winding, the rectifier, and the motor series field winding, the polarity sense of the rectifier being such that the motor series field winding acts cumulatively to the main motor field winding when the output voltage of the generator has a given polarity, rheostatic control means for changing the ex
  • a generator and motor having their armature windings connected in a loop circuit, main field windings for the generator and motor, said loop circuit further including a series field winding for the generator, a shuntcircuit including switching means for effecting the shunting of the generator series field winding, a motor series field winding, a rectifier connected in series with the motor series field winding, and rheostatic control means operatively associated with the shunting circuit for the generator series field winding and connected in relation to the motor series field winding for changing the excitation current of the motor series field winding, and
  • rheostatic control means for the generator main field winding for controlling the motor speed.
  • a generator and motor having their armature windings conected in a loop circuit, main field windlogs for the generator and motor, said loop circuit further including a generator series field winding, a rectifier and a motor series field winding all three connected in a series circuit, a resistor connected in parallel to said series circult, and generator series field shunting circuit means connected at any selected point on said resistor and including switching means for effecting the shunting of the generator series field winding, and rheostatic control means for the main field winding of the generator for controlling the speed of the motor.
  • a generator and motor having their armature windings connected in a loop circuit, main field windings for the generator and motor, said loop circuit further including a series field winding for the generator, a shunting circuit including switching means for eitecting the shunting of the generator series field winding, a motor series field winding, a rectifier connected in series with the motor series field winding, and rheostatic control means operatively associated with the shunting circuit for the generator series field winding and connected in relation to the motor series field winding for changing the excitation current of the motor series field winding, rheostatic control means for the main field winding of the generator for changing the generator excitation from zero by successive values to a selected high value, rheostatic control means for changing the excitation of the main field winding of the motor, and means operable by said rheostatic control means for causing the operation of said switching means included in the loop circuit to effect
  • a generator and motor having their armature windings connected in a loop circuit, main field windings for the generator, rheostatic means for varying the excitation of the generator main field winding from Zero in successive steps to a selected high value, rheostatic control means for the main field winding of the motor, said loop circuit further including a series field winding, a rectifier, and a series field winding for the motor all three connected in a series circuit, a resistor having a plurality of sections connected in parallel to said series circuit, a shunt circuit for the generator series field winding, a shunt circuit for said resistor connectible across any selected number of resistor sections, switching means for closing the shunt circuits, and means responsive to the operation of said rheostatic means of the main field winding of the generator for effecting the closing of said switching means at Zero excitation of the main field winding of the generator and for the lowest excitation of the main field wind
  • a generator and motor having their armature windings connected in a loop circuit, main field windings for the generator, rheostatic means for varying the excitation of the generator main field winding from zero in successive steps to a selected high value, means responsive to the motor load current for effecting an excitation of the main field winding of the generator greater than said selected high value when the motor load current is below a selected value, rheostatic control means for the main field winding of the motor, said loop circuit further including a series field winding, a rectifier, and a series field winding for the motor all three connected in a series circuit, a resistor having a plurality of sections connected in parallel to said series circuit, a shunt circuit for the generator series field winding, a shunt circuit for said resistor connectible across any selected number of resistor sections, switching means for closing the shunt circuits, and means responsive to the operation of said rheostatic means of the
  • a generator and motor having their armature windings connected in a loop circuit, main field windings for the generator, rheostatic means for varying the excitation of the generator main field winding from zero in successive steps to a selected high value, rheostatic control means for the main field winding of the motor, said loop circuit further including a series field winding, a rectifier, and a series field winding for the motor all three connected in a series circuit, a resistor having a plurality of sections connected in parallel to said series circuit, a shunt circuit for the generator series field Winding, a shunt circuit for said resistor connectible across any selected number of resistor sections, switching means for closing the shunt circuits, and means responsive to the operation of said rheostatic means of the main field winding of the generator for effecting the closing of said switching means at zero excitation of the rain field winding of the generator and for the lowest excitation of the main field wind
  • a generator and motor having their armature windings connected in a loop circuit, main field windings for the generator, rheostatic means for varying the excitation of the generator main field winding from zero in successive steps to a selected high value, means responsive to the motor load current for efi'ecting an excitation of the main field winding of the generator greater than said selected high value when the motor load current is below a selected value, rheostatic control means for the main field winding of the motor, said loop circuit further including a series field winding, a rectifier, and a series field winding for the motor all three connected in a series circuit, a resistor having a plurality of sections connected in parallel to said series circuit, a shunt circuit for the generator series field winding, a shunt circuit for said resistor connectible across any selected number of resistor sections, switching means for closing the shunt circuits, and means responsive to the operation of said r
  • a variable voltage system for hoists for hoists, a generator, a compound motor supplied thereby and having a series field winding, means to effect reverse operations of said motor by reversing the polarity of a field winding of said generator and to vary the excitation of said generator to provide for said motor a plurality of hoist and lowering speed points, and means associated with the former means including a rectifier to eflect inclusion of said motor series field winding on all lowering points under overhauling load conditions and to exclude said motor series field winding from circuit under power lowering conditions.
  • a generator in combination, a generator, 2. compound motor supplied thereby and having an auxiliary series field winding, means to effect reverse operations of said motor by reversing the polarity of field winding of said generator and to vary the excitation of said genera-tor to provide for said motor a plurality of hoist and lowering speed points, and rectifier means connected in series with said motor auxiliary field winding for effecting inclusion of said latter winding on all lowering points under overhauling conditions.
  • a generator in combination, a generator, a compound motor supplied thereby and having an auxiliary series field winding, control means for said generator for effecting reverse operation of said motor and providing a plurality of speed points therefor, and rectifier means connected in series with said auxiliary series field winding for permitting energization thereof under certain conditions of hoist operation and blocking energization thereof under certain other conditions.
  • a generator 21 compound motor connected in a loop circuit therewith and having an auxiliary field winding connected in parallel with a voltage drop resistor in said loop circuit, control means for said generator for varying the loop circuit voltage and for reversing the polarity thereof, and a blocking rectifier connected in series with said motor auxiliary winding to prevent energization thereof during light line lowering conditions.
  • a generator in combination, a generator, a compound motor connected in a loop circuit therewith and having an auxiliary field winding, a voltage drop resistor in said loop circuit with said auxiliary field winding connected in parallel therewith, control means for said generator to effect reversal of the voltage polarity in said loop circuit and consequent reversal of said motor and for varying the excitation of said generator to provide for said motor a plurality of hoist and lowering speed points, and a blocking rectifier, said rectifier being connected in series with said auxiliary field winding to prevent energization thereof when said motor is driven in the lowering direction by said generator.
  • a variable voltage control system for hoists in combination, a generator, a compound motor supplied thereby and having an auxiliary series field winding to be excluded from circuit under certain conditions, means to effect reverse operations of said motor by reversing the polarity of a field winding of said generator and to vary the excitation of said generator to provide for said motor a plurality of hoist and lowering speed points, and means responsive to direction of load current through the armature of said motor to disconnect said auxiliary series field winding from circuit for power lowering, said last mentioned means comprising a rectifier connected in series with said auxiliary field winding.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Eletrric Generators (AREA)
US245372A 1951-09-06 1951-09-06 Adjustable voltage drive Expired - Lifetime US2785362A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CA551402A CA551402A (fr) 1951-09-06 Commande ajustable de voltage
US245372A US2785362A (en) 1951-09-06 1951-09-06 Adjustable voltage drive

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CA551402T
US245372A US2785362A (en) 1951-09-06 1951-09-06 Adjustable voltage drive

Publications (1)

Publication Number Publication Date
US2785362A true US2785362A (en) 1957-03-12

Family

ID=72848754

Family Applications (1)

Application Number Title Priority Date Filing Date
US245372A Expired - Lifetime US2785362A (en) 1951-09-06 1951-09-06 Adjustable voltage drive

Country Status (2)

Country Link
US (1) US2785362A (fr)
CA (1) CA551402A (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3121833A (en) * 1961-06-27 1964-02-18 Westinghouse Electric Corp Ward-leonard adjustable voltage motor hoist drive
US3218536A (en) * 1963-01-25 1965-11-16 Westinghouse Electric Corp System for regulating above-synchronous speed of an a.c. motor
DE1227217B (de) * 1961-06-27 1966-10-20 Westinghouse Electric Corp Hebezeugantrieb mit Gleichstrommotor in Leonard-Schaltung
US3297110A (en) * 1965-02-10 1967-01-10 Serge Elevator Company Inc Generator starter used in an elevator motor drive
US3407904A (en) * 1964-11-24 1968-10-29 Ingersoll Rand Canada Hoist apparatus including current sensitive motor control means to hold a variably loaded cage chaired

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2320841A (en) * 1940-10-26 1943-06-01 Westinghouse Electric & Mfg Co Polarized-field generator
US2420873A (en) * 1943-07-03 1947-05-20 Westinghouse Electric Corp "rectox" motor control system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2320841A (en) * 1940-10-26 1943-06-01 Westinghouse Electric & Mfg Co Polarized-field generator
US2420873A (en) * 1943-07-03 1947-05-20 Westinghouse Electric Corp "rectox" motor control system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3121833A (en) * 1961-06-27 1964-02-18 Westinghouse Electric Corp Ward-leonard adjustable voltage motor hoist drive
DE1227217B (de) * 1961-06-27 1966-10-20 Westinghouse Electric Corp Hebezeugantrieb mit Gleichstrommotor in Leonard-Schaltung
US3218536A (en) * 1963-01-25 1965-11-16 Westinghouse Electric Corp System for regulating above-synchronous speed of an a.c. motor
US3407904A (en) * 1964-11-24 1968-10-29 Ingersoll Rand Canada Hoist apparatus including current sensitive motor control means to hold a variably loaded cage chaired
US3297110A (en) * 1965-02-10 1967-01-10 Serge Elevator Company Inc Generator starter used in an elevator motor drive

Also Published As

Publication number Publication date
CA551402A (fr) 1958-01-07

Similar Documents

Publication Publication Date Title
US2301689A (en) Control system
US2785362A (en) Adjustable voltage drive
US2581292A (en) Control system for induction motors and braking generator combination
US2687505A (en) Control system for induction motors and braking generators using saturable core reactors
US2766415A (en) Magnetic amplifier motor control system
US2774923A (en) Electric control for alternatingcurrent motor
US2494611A (en) Antiplugging control for motors
US2468117A (en) Variable voltage drive, particularly for hoisting equipment
US2534423A (en) Braking system for induction motors
US2420873A (en) "rectox" motor control system
US1503245A (en) Motor controller
US2298188A (en) Motor control system
US2970251A (en) Electric control for alternating-current motor
US2445460A (en) Dynamic braking system
US2255488A (en) Control system
US1497448A (en) Motor-control system
US2367956A (en) Motor control system
US2406426A (en) Control system
US2238622A (en) Hoist control
US2628336A (en) Variable voltage motor control system
US2488210A (en) Control system for an induction motor and braking generator combination
US1884446A (en) Motor-control system
US1669518A (en) Elevator control system
US2515612A (en) Motor control system
US2569317A (en) Control system