US851291A - Starting device for hoisting-machines. - Google Patents

Description

PATENTED APR. 23, 1907.

J. D. IHLDER.

STARTING DEVICE FOR HOISTING MACHINES.

APPLICATION FILED JULY 23, 1904.

INVENTOH WITNESSES: Z/

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JOHN D, IHLDER, or YONKERS NEW YORK, ASSIGNOR TO OTIS ELEVATOR COMPANY, Oll EAsTORANGE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

Specification of Letters Patent.

Patented April 23, 1907.

Application filed July 23, 1904. Serial No. 217,758.

short-circuiting that part of theresistance 30 1'0 all whom it may concern ,Be it known that I, JOHN D. IHLDER, a citizen of the United States, residing at Yonkers, in the county of WVestc-hester and State of New York, have invented certain new and useful Improvements inStarting Devices for Hoisting-Machines, of which the following is a specification.

My invention relates to starting devices for motors, especially those applied to hoistmg apparatus, and is more especially applicable to hoisting machinesin which there is more or less slack cable to be wound up be fore the actual load comes on. Its ObJGCt 18 to provide an arrangement which insures an easy starting of the machine and prevents it from unduly accelerating. While such slack cableis being woundup and'which automatically applies fullpower to the hoisting machine-as soon as the load itself comes on.

The accompanying drawing represents dia grammatically the arrangement of circuits electric motor which'is connected to and op, crates the hoisting mechanism. The hoist-' ing mechanism itself forms no part of this invention so it is not shown in the drawing.

23 designates the motor armature, 2-2 and 21 the commutator brushes, and 24 the shunt field which is connected across the line by the wires 25 and 26 while the switch 10 is closed.

30 designates a starting resistance in series with the motor armature which is adapted to be cut out or short-circuited in a number of successive steps automatically by means of the. magnet 40. This magnet 40 controls the movable contacts 31, 32, 33, 34

and 35 and these movable contacts make contact one after the other with the stationary contacts 36, 37, 38, 39 and 41 respectively. It will be seen that when the contact 31 under influence of the magnet 40 is drawn agaiIfSt contact 36, there is established a circuit of very low resistance through the wire 15, contacts 36, 31, and wire 16, thus included between the wires 15 and 16. In a similar manner the remainder of-the resistance is short-circuited step by the current finally flows through the shunt formed by the wire 15, contacts 41, 35, and wire 17. The magnet 40 is connected directly across the brushes of the motor armature so that it depends for its operation upon the potential across the brushes and consequently upon the speed of the motor. Its movable contacts/ are arranged to be pulled inone by one as the motor accelerates, by being placed at different distances from the magnet, or by other means of adjustment.

designates an auxiliary resistance which is controlled by a magnet 70. This "magnet is connected in like manner across the armature of the motor but has a switch 53 included in its circuit. The magnet 70 controls the movable contacts 74, and 76 which are connected together by the wire and which as shown are normally in contact with the stationary contacts 77, 78 and-79 respectively. When, however, the magnet 70 is energized, the contacts 74, 75 and 76 are drawn away one by one from the con tacts 77, 78' and 7 9'respectively, thus breaking all electrical'connections between them. The drawing shows the magnet 70 as having three movable contacts, but more or less can be used as desired. The small governing switch 53 comprises an arm 57 carrying a contact 55 which is held against the contact 54 by a spring 56. This arm is controlled by step, so that a magnet 50 which has two windings. One

of these, designated by 52, is a series windin in series with the motorarmature connected to the contacts 74, 75 and 76 by the wire 80, and to the armature brush 21 by the wire 58. The other winding 51 is in shunt tothat portion of the resistance 60 included between the wires 65 and 66. The coil 52 is so designed that it is not of sufiicient strength to open the governing switch but may hold it in open position after being operated by the coil 51, and even after the coil 51 is partially or wholly unexcitcd. When the magnet 70 is de-energized as shown in the-drawing, there is established through the contacts 74, 77; 75, 78; and 76, 79 a shunt circuit of very low resistance which practically amounts to a short-circuit between the armature brush 21 and the main. If, however, the magnet 70 is slightly energized it will' attract its nearest contact 76, thus breaking the circuit between the contacts 76 and 79. This opera'tion will open the short-circuit across that portionof theauxiliary resistance 60 VVlllCll, is included between the wires 82 and 83 and which is designated by 64. In a sim1lar manner, the contacts 75 and 74 on being separated from the contacts 78 and 77 respectively as the magnet 70 increases in strength, will introduce into the armature circuit that portion of the auxiliaryresistance 60 in cluded between the wires 81, 82 and 81, 58-

respectively. This last step will put the re: sistance 61 into circuit. The Winding 51 of the governing magnet 50 is in shunt to thls portion of the resistance, so that it Will now receive a certain amount of current proportional to that passing through this resistance and the motor armature.

I will now describe the operation of my device. On closing the starting switch 10, the motor field 24 is at once energized to full strength as it is connected directly across the mains. The armature circuit is established at the same time and current flows from the positive '01 main, through the wire 14, resistance 30, armature 23, Wire 58, coil 52, and the wires 80, 83 and 84 to the main. The armature will. now start to revolve, its current being limited by the resistance 30 to an amount just sufficient to overcome the friction of rest. .As the armature accelerates the potential across its brushes will become greater. When this has reached a predetermined strength corresponding to the desired slow speed, the magnet 70 which is connected across the motor armature will pull its movable contacts 76, 75 and 74 away from the contacts 79, 78 and 77 respectively one after the other, thereby introducing into 'the armature circuit the additional resistwinding up the loose cable.

ance so that the armature current is reduced and the motor is kept from rotating faster than the-desired slow speed while it winds up the slack cable. The coil 51 of the magnet 50 being in shunt to a portion 61. of the resistance 60, included between the wires and 66, will receive a small amount of current but not enough to attract its armature I 57. The series coil of the magnet 50, i. e. the .coil 52 is not of suflicient strength to move the arm 57 against the spring 56 upon start ing the motor and as soon as the contacts 76, 75 and 74 are raised its circuit is opened and it does not exert an infiuencep The OlIOllltS'Wlll remain in this condition as long as the motor'is not called upon to do any work above overcoming its own friction and As soon, however, as a strain comes on the hoisting cable and a load is put upon the motor, the current in its armature will increase, conse quently the current passing through the portion .61 of the resistance and through the coil 51 will increase. The current which passes through the coil 51 will now become of sufficient strength to cause the magnet 50 to attract its armature 57, so that the circuit of the coil of magnet is opened at the contacts 54 and 55. Consequently the contacts 74', 7.5 and 76 return to their initial position against the contacts 77, 78 and 79 respectively, and short-circuit the entire resistance 60 The current will now flow through the resistance 30 and the armature from the brush 21 to the wire 58, through the coil 52, wires 80, 83 and 84, and so to the negative main. As soon as the resistance 60 is short-circuited, the coil 51. of the magnet 50 is also short-circuited, so that this coil will not have a tendencv to become heated during the running of the motor. The magnet 50 would at once become deenergized and allow its armature 57 to be .moved by the spring 56 so as to connect the contact 54 with the contact 55, but it will be seen that the instant the resistance 60 is short-circuited, the armature current flows through the coil 52 and this gives the magnet suflicient strength to keep the contacts 54 and 55 separated and prevent the magnet 70 from getting any current. Consequently the resistance 60 is kept short-circuited. While these operations have been taking place, the voltage across the armature brushes has not risen to a value sufficientl v high to cause the contacts 31, 32, 33, 34 and 35 to operate, so that the resistance 30 has all of this time been in circuit. As the resistance 60 has now been short-circuited, the armature will speed up. This produces a rise of voltage across the armature brushes, and the current through the magnet 40 will become of sufficient strength to cause it to operate and-to attract the movable contacts 31, 32, 33, 34 and. 35 These contacts are set to operate in sequence and at predetermined voltages corresponding to predetermined rates of speed of the motor armature.- As soon as the magnet 40 causes the contact 31 to connect with phe contact 36, a part of the resistance 30 wi 1 be short-circuited. As the contacts 32, 33 and 34 are closed upon contacts 37, 38 and 39, more of the resistance 30 is short-circuited and when contact 35 is closed upon contact 41 all of the resistance 30 will he short-circuited and the motor armature will now receive current at the full line potential with no starting resistance in circuit. The motor circuit under the present conditions will be from the 'positive main through. the wires 14, 15, 17, brush 22, brush 21, wire 58, coil52, wires 80, 83, 84, and thus to the or negative main.

This invention may be applied to any arrangement wherein it is desired to have a motor run slowly until its load comes upon it and then to have its full power applied.

--of circuit when a loadcomes upon the motor and for holding the latter resistance out of circuit.

2. "In a controller for electric motors, the combination of two starting resistances each directly connected to the motorarmature,

- andmeans for cutting one of the resistances out of circuit when a load comes upon the 3. In a controller for. electric motors, the combination of two starting resistances one normally in circuit and the, other normally out of circuit'with the motor armature, and

' means for inserting said other resistance upon starting the motor and cutting out said resistance when a load comes upon the motor. fl. In a controller for electric motors, the combinaticfi of two starting resistances, and means for automatically inserting one of said resistancesupon starting the motor and for automatically short-circuitingsaid resistance when a load comes upon the'motor.

5. In a controller for electric motors, the combination of a starting resistance in circuit with the motor, an additional resistance in circuit with the motor, and means for .controlling said additional resistance to revent acceleration of the motor until a loa comes upon the said motor.

v 6. In a controller for electric motors, the combination of two starting resistances, means for. inserting one of said resistances upon starting the motor and for gradually cutting said resistance out of circuit when a load comes upon the motor, and means for cutting out the othei'resistance to accelerate the motor.

7. In a controller for electric motors, the combination of a starting resistance in series with the motor-armature, means for varying said resistance to change the sp'eed of the 7 motor, an additional resistance in series with load is connectedto themotor.

themotor-armature, and means for controlling said additionalresistance to prevent acceleration of the motor until. a predetermined 1- 8. In a controller for electric motors, the combination of a sectional starting resistance in circuit with the motor-armature,.an auxil- .iary sectional starting resistance. in circuit with-the.,motor-armature, means for auto-1 matically' controlling said -yauxiliaryresistance --to V I e motor, i meane fofi shortcircuitingthe said auxiliaryresistanc; and means gradually rnsert the same upon,

starting '0 controlling said sectional which is in circuit upon starting the motor,

automatic means for putting the second resistance into the circuit to prevent the acceleration of the motor and for removing said I second resistance from the circuit when the,

motor armature current increases.

' 11. In a controller for electric motors, the combination of two adjustable resistances, the first of which is in circuit upon starting the motor, automatic means for putting the second resistance into the circuit to prevent the acceleration of the motor-and for removing said second resistance from the circuit' when the motor armature current increases,

4 and automatic means for gradually removing said first resistance from thecircuit as the motor accelerates. I

12. In a controller for electric motors, the combination of a starting resistance, an auxiliary resistance, 'a magnetic switch for putting the auxiliary resistance into circuit, and

.a governing'magnet controlling said mag-- netic switch.

18'. In acontroller for electric motors, the- I combination of a pluralityof resistances, a

magnetic switch for inserting one of'saidresistances 1n the motor circuit, means for controlling saidmagnetic switch, and means for-- operating the other resistances to'vary-the speed of the motor. I 14. In a controller for electric motors, the

combination of a starting resistance, an aux-' iliary resistance, a magnetic switch-for grad- IIO ually inserting said resistance into circuit with the motorarmature,' and a governing magnet for controlling said magnetic switch.

15. In a controller for electric motors, the combination of starting'resistance, an aux-v iliary resistance, amagnetic. switch .for controlling said au'xiliary resistance, and a gov' erning magnet for said magnetic switch,-said governing magnet having two' coils, onecoil being connected to the auxiliary resistance and the other coil being in serieswi'th the mo- 'tor armature.

16.;In a controller for electric inot'ors, the combination of a starting resistance, anamp; iliary resis tance,',a" magnetic switch forcOn-I t'rolling; said auxiliary resistance,' .an. 'addi- ,tional switclrior. controlEng said magnetic switch; and an -electromagnet foroperating sa'id additional switch, said electromagnet having two; windings; oneybeing connected to iliary resistance, a magnetic switch for conother being in circuit with the motor-armature and serving to hold said additional switch in open position.

17. In a controller for electric motors, the combination of a starting resistance, an auxtrolling' said auxiliary resistance, an additional switch for controlling said magnetic switch, and an electroinagnet for operating said additional switch, said olectromagnet having two windings, one winding being connected in shunt to a portion of said auxiliary resistance and the other winding being connected in series with the motor-armature.

' 18. In a controller for electric motors, the

combination of a starting resistance, an auxiliary resistance, a magnetic switch for automatically controlling the auxiliary resistance,

and a magnet controlling the magnetic switch having a winding connected to said auxiliary resistance and a winding in series with the motor armature.

19. In a controller for electric motors, the combination of a starting resistance, means for automatically controlling the starting resistance, an auxiliary resistance, a magnetic switch for automatically controlling the aux iliary resistance, and a magnet controlling the magnetic switch having a winding connected to said auxiliary resistance and a wind ing in series with the motor armature.

In testimony whereof, I have signed my name in the presence of two subscribing wit- HGSSQS.

' I JOHN D. IHLDER. Witnesses WALTER C. STRANG,

ERNEST W. MA-RsnALL.

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