US921989A - Automatic motor-starter. - Google Patents

Description

W. I. HEHDRY. AUTOMATIG mo'ron STARTER. APPLICATION FILED DEC. 21. 1905.

9%1 ,989. Patented May 18, 1909. c 2 SHEETS-RESET 1.

jkzz en (07" W. I. HENDRY. AUTOMATIG MOTOR STARTER.

APPLICATION FILED DBO. 21,1905.

2 SHEETS-SHEET 2.

Patented May 18, 1909.

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"aw j UNITED STATES PATEN T OFFICE.

WILLIAM F. HENDRY, OF NEW YORK. N. Y., ASSIGNOH TU WESTERN El.l'j("lltl( COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION )l ILLINOIS.

AUTOMATIC MOTOR-STARTER.

Specific tion of Letters Patent.

Patented May 18, 1909.

Application filed December 21, 1905. Serial No. 292,817.

To all whom it may concern:

Be it known that I, WILLIAM F. HENDRY, a citizen of the United States, residing at New York, inthe, county of New York and State of New York, have invented a certain new and useful Improvement in Automatic Motor-Starters, of which the following is a; full, clear, concise, and exact description.

My invention relates to motor starting devices, and its. object is to provide auto msticmeens i or greduelly cutting out the starting resistance of electric motors.

Prior to my invention all motor starters of the automatic type, commonly called selfstsrte'rs, were operated by one or more solenoids, which may close the line circuit nndjwhich short circuit the starting resistance. These solenoidskrequire a certain amount of currentto hold their switches tightly closed, and herein lies one of the great objections to automatic starters.

M invention broadly comprises an automatic starter which uses no current after it has performed its function of starting the motor. In my invention the devices for cutting out the starting resistance, and preferably also the device or devices for closing the circuit, lock themselves in their runnin position, but open automatical y in (use oi fuilure of the current supply or an excess of current. Said devices preferablv consist of solenoid switches provided with mechanical self-locking means for retaining said switches in closed position. and additional means, underthecontrol of the operator, for opening said switches said means being also nutomatieiilly operated in case of overload or underloed. v 4

An additional feature of my invention is the provision o f mcenswhereby an external source of energ ;rel $itl,ie:-e| 1tire apparatus in ciiseof feiugei tl e cnrrent supply. lci mstem sw et en gy m y ,used prefershlypinpioc thei energy? developed lh ythe, m me, qf t 1e ,revolving motor sometime i, ema phinerygwhich it may be driving to, oirrpl sh this purpose. w

hesejoiid vent onwill liekpore reed; y ,understood by referencetb ti liwsempsi ri s i-s i in which 4,]

Figure} s1 sfjdi 'fi, rscus' ands-nests, gnployed, in ,my invention; Figs; 25nd 3Ergfront endsidejcl'ova he sw ll. new o m the oippa tions, res ectively, of the self-locking solenoid switc employed in my invention.

Similar letters of reference refer to similar parts wherever they are used.

The apparatus comprises two solenoids A and G for operating switches a and a, respectively, which close the circuit of the main line; solenoids M, N, P and B controlling switches m, n, p and b, respectively, for radually cutting out the starting resistance ll of the motor armature; three trippin magnets T, T, T, adopted when energized to actuate means for unlocking switches a, b, 0, respectively; a. master rheostat solenoid S actuating a lever L for controlling the admission of current to the coils of the solenoids M, N, P and B; a solenoid or broke coil L, controlling brake mechanism of the lever L; a relay D controlling a short circult about the brake coil L; and on overload lLDt'l underloud relay 0.

The plungers of the solenoids A, B and (J are extended below the switches a b 0, respectively, and are su )ported whensaid solenoids ore deenergizeil, upon the base of the brackets t, the lugs 15 of which as shown in Fig. 2, act as guides for said plungers. The lower end of each of these plungers has a groove G cut in it. A trigger or latch E is supported above the magnet 'l and carries on one end a roller 1:. when the solenoid plunger is raised to close the switch, a spring 12, as shown in Fig. 3, or c as shown in h ig. 1, causes the roller 0 of the latch E to en age the groove G and thus hold the switch in closed position, regurdless of whether or not the solenoid is energized.

For the purpose of unlocking the hitches E and releasing the plungers oi the solenoids A, B, C, the tripping magnets T, 'l", T, rc spcctively, are provided. The encrgiz'stion of these magnets, as will be hcrcnlter described, is under the control of a stop button V, as well as the overload and under-load coil 0. When meg-nets 'l, T, 'l are enerized, their core pieces or plun crs F are drawn up and the pin f is actuated to deliver a blow upon the lever E sulliciently to overcome the tension of the spring e or 6 The roller 2 is thus withdrawn from the groove G, per ittin the corresponding switch to be 0 nod. hile I have shown the latch E a pted to be locked by the aprin e or 'e a to be unloclrcd hy the-colour 's 'l, T.

T, I do not wish to limit myself to this particular arran ement, as obviously changes mi ht be made to meet specialcases.

y operating the starting switch \V, a circuit is closed from the mains throu h the solenoids A and U. The windings 0 these solenoids are connected across the line in series with each other parallel circuit, one branch of which passes rom the point 5 through the lamp resistance H to the point 4. The other branch extends from the point 5 through a switch 6', closed when the solenoid B is denergized, and from thence through switches m, n, 1), closed when solenoids M, N and I, respectively, are denergized, to the point 4. W hen the last described branch is open, the current flowing through the other branch, owing to the high resistance of the lamp H, is insufficient to energize the solenoids A and C sufficiently to close the corresponding switches a and c. The solenoids A and G are. further rovided with switches a, 0, respectively. baid switches break the main circuit and are located in the strong magnetic field of powerful blowout coils a 0 which disrupt the arcs. When the parts are in normal condition, however, the closing of the switch W causes the solenoids A and C to close the main line switches a and c res ectively. When the switches a and c are c osed the latches E serve to retain them in the closed position, as above described, and hence the necessity for a con-tinned ilow of current throu h the solenoids A and O is eliminated. There ore when the operator removes his finger from the push button W, the current through said so enoids is cut off, but the switches a and 0 remain closed.

When the switches a and c are closed a circuit is completed from positive terminal of the mains, through switch a, .the motor armature Y, the resistance R to the oint l, and from thence through the relay to the point 2, and from thence through the switch 0 to the ne ative terminal of the mains. The shunt field ofthe motor armature extends from thepoint 3 through the shunt field resistance to the point 2 and is other ized as soon as switches A and C are close The resistance R is arranged in a lurality of steps or blocks R, R", R, l t plungers of the solenoids M, N, P and B operate switches m, n, p and b, respectively, for successively cutting out these steps of blocks of resistance It. While for the purpose of description I have shown the armature resistance arranged in four blocks and adapted to be cut out by four switches, it is obvious that any desired number of blocks and switches may be used.

As shown in Fig. l, the circuits through the windings of solenoids M, N, P and B are normally open at the contact buttons m, n, p and respectively. .Said contacts are and in series with a.

The

tivo terminal of the mains.

solenoid S, said plunger having a slot in its lower end throu which it is nected by a pin to the lever L.

When the switches a and c are closed in the act of starting the motor, a circuit is also completed through the switch a-, the point 7, the switch I) at the top of solenoid B, the solenoid S, the point 8, the solenoid or brake coil I1, point 6, point I, and from thence through the relay and switch 0 to the nega- A short circuit pivotally con of the windings of the solenoid L extends from the point-8 to the point 6, throu h the contact point d and lever L said s ort circuit being closed at one of the huttons x, m, n or p, and bein controlled by the armature d of the relay ]5 at the contact d.

The relay D is in series with the armature circuit, its windings being included in a parallel branch circuit extending from the point 10 to the point 1.

The

plunger of the solenoid L is normal] held u ward by a spring I. A lever L is pivote at one end to said plunger, and its other end is pivoted to the framework at l. A band Z passes around the enlarged circular end or drum L of the lever L, the ends of the bands being secured at difierent points on the lever L. As a result of this construction, when the solenoid or brake coil L is energized and draws in its lungcr, the lever L is rocked on its fulcrum If, and the band I is tightly drawn over the drum I acting-as a brake upon the movement of thelever J- The starting resistance R may be of such value as will allow a current to pass of any predetermined amount, say about fifty per cent. above the normal running current of the motor. The relay D is adjustedto operate at this current and opens contact thus opening the short'circuit around the brake coil L, allowing said coil to be energized and thereby preventing the master solenoid S from moving the lever L over the contacts 7R8: 7113, P motor armature speeds u the flow of current in the circuit, including relay D, is reduced thereby and the relay D releases its armature d, thus closing contact d. The short circuit about the windin s of solenoid l3 bein closed at contacts and 2, said solenoid is denergized and its plunger is retracted by the spring I, carrying with it the end of the lever L, and thus loosening the band 1, thew removing the brakefrom the lever L. 1e solenoid S is than free to move the lever L over the double row of contacts,'and when said lever rests on-the contact button m", a branch circuilizz com leted through the windings of the sol oid ll contact m, lever L to point 6. The energizeas before described. As the tion o'lsolenoid M closes the switch m and f of starting; 7

above no'rnuil, and the relay l) attracts its armature and opens the short circuit about the brake coil L. which thereupon becoming energized prevents further movement of the i is the motor speeds up, the current decreases, the relay l) releases its armature 5 lever L.

and the. brake coil l; is shortcircuited through contact 5/, switch. m contact button In and lover 1/.

draw the lever I1, over th row of contacts to the contact, button a, whereupon the solenoid N is energized and cu ts out an additional block R of resistance. This operation of gradually cutting out ste s of resistance continues as the motor speed; 11

It will be observed that unless the solenoid M has previously operated to cut out a block of resistance and at the same time to close the switch m, the short circuit about the brake coil. L, even though closed at contacts (1 and M will still be open at said switch m and hence the brake upon lever L will be maintained. It is apparent therefore-that the lever L cannot'advance beyond contacts m, n, or 79 until the corresponding magnet M, N, or P has operated and thereby closed the corresponding switch m n, or p.

When the level L reaches the last contact button b, the solenoid B is energized and closes the switch I), which switch is held in closed position by the latch E. The closing of switch'b cuts out the last step R of the resistance and at the same time short-cirsuits the relay I which is in shunt with the said block R* of resistance.

As the solenoid B raises its plunger, the switch 6 is o erat'ed, to open the circuit through the solenoids S and L. Thereupon the lever L is returned by the force of gravity to its initial position against the sto 'y and rests upon the button a: and the dearrbutton z. In case the lever should stick at any of the intermediate contacts m, n, p or b, thereby energizing the corresponding resist-- ance solenoid and cutting out' armature resistance, the corres )onding switch m, n, p or b at the top 0 said resistance solenoid would be 0 ened an it would be impossible to start t e motor until said resistance solenoid had been de'nergized b moving the lever to the initial position. his is due to the fact that with their circuits open at an y of the switches m,n, por bthe solenoids A and 9 would not receive enou h current thro'u h the branch including the amp H'to close the switches a and c. In the initial position of the lever the resistance solenoids Th allows the master solenoid S to further raise its plunger and to further can receivc no current, as the lever then rests on the dead button 2.

. From the foregoing description ol the operation oi my automatic motor starter it is the parts in normal posiapparent that will armature circuit im tiou, as shown in Fig. 1, a momentary closing ton is sullicicljt to close switches a and c, which are mechanically Q locked in closed position. The release of the starting button opens the circuit of solenoids A nd t which receive current only as long as is necessary to close their switches. It is of the starting but is energized to close switch I), which is also mechanically locked in closed position, thereby cutting out all of the starting resistancclt, or in other words, as soon as the motor has i gotten up to full speed, the flow of current through the main switch operating solenoids A and C, 'as well as throu h the resistance controlling solenoids M, P and B, the master rheostat solenoid S, the brake coil L and the relay D is entirely eliminated. This not only protects said magnets and prolongs their utility but results in a saving of the current.

As before stated, the latches E,which hold the switches a b 0 closed are under the control of tripping magnets T, T, T, respectively. Said magnets are in turn under the control of a stop button V and an overload and underload coil 0.

W'hen it is desired to cut off the current fromthe motor to stop the same, this is accomplished by pressing the sto button V. A circuit across the line throng 1 the rela s T, T, T is thus closed, which circuit may e traced as follows: from the plus terminal throu h the windin of relavs T, T, T, contact c osed by stop i utton V, switch b, point 1, relay 0, point 2, switch 0 to minus terminal of the mains. As before described gization of relays T, T, T causes their plun gers to o crate to release the rollers 41 of the atches from the grooves G in the plungers of solenoids A, B, C, permitting said plunger-s to fall by gravity and open switches a-, b, 0 thereby cutting off the current from the motor and restoring the parts to their initial position shown in Fig. 1.

The starter is also provided with a specially designed overload and underload device which consists of the ordinary overload coil 0 with two armatures 0 and 0', one at each end of the relay.- The armature o is calibrated to be drawn up in case of overload. The armature o is arranged to be drawn up at, say, about five per cent. of full load cur rent in opposition to a sprin 0 which tends to 1111 the armatures o and 0 away.

he oveiload armature1 0 provides for automation; 1 o erat' t e tri 1' ma nets T, 'I",.l, in case fian exces sli v flow f current through the armature circuit, thus also apparent that as soon as the solenoid H' the enerprotecting the motor from possible" injury 13o Switches 6 and c are stil of solenoid B is 0 en,

therefrom. In case of such excessive flow of current, the armature o is drawn up closing contact 0 A circuit is thus closed through the tripping magnets, which circuit may )e traced as follows: from the positive terminal through switch a, windings of magnets 'l, T, T, contact 0, switch b, point I, and 'rom thence through the coils of relay 0 to the negative terminal. The energization of said trip in magnets operates in the manner revious y escribed to open the switches a 1 and c and cut oil the flow of current from the motor.

The underload armature 0 is arranged to be drawn up at say, about five per cent. of full load current. When the current dies down below this point or entirely fails the spring 0 retracts the armature 0, thereby ermitting the spring 0 to close contact 0 11 case the current does not entirely fail, the line itself, upon the closing of contact 0, furnishes current for energizing the coil of tripping ma net T. The circuit through relay 1, in t is event, may be traced from the positive terminal through switch a, relav T, point 11, contact 0, point 12, switch 5, point 1, and from thence through the coil of relay 0 to the negative terminal. In case the supply of current entirely fails, an arrangement of circuits is provided for utilizing electromotive force generated "by the revolving armature of the motor, which will run long enough to furnish the slight amount of current required to energize the magnet T to tri the latch E. This circuit may be trace as follows: from one side of the armature Y, through point 3, soil of magnet T, point 11, contact 0, points 12 and 9, to the opposite side of armature Y. The counter eectromotive force furnishes a current of suflicient strength to energize the tri ping magnet E and cause it to'accomplis its function, thereby openin the main switch a. I closed, and hence the switch b at the to thereby preventing tlib coils of solenoi s A and C from receiving the allotted current required to close the main switches. It will be necessary, therefore, to push the stop button V, as soon as the source of supply is again restored, and energize the tripping magnets T, T, before the motor can again be started. By this provision of an underload armature o, if the current supply should fail, or die down below a predetermined amount, the motor is full protected from anyIsubsequent sudden rus of current.

aving thus described my invention, I claim:

1. Ina motor starting device, the combination with a motor having a resistance included in the circuit of its: armature, of an electromagnet, a switch operated thereby for cutting out said resistance, means independent of the energization of said electromagnet during for locking said switch in its closed position, means for opening the circuit of said solenoid and thereby eliminating the consumption of current by said starting device, when said resistance is entirely out out, a restoring elec-- tromagnet haviflg a circuit normally open the closure of said switch, and means for closing the circuit of said restoring electromagnet, said electromagnet being adapted upon its energization to release said switch from its locked condition.

2. A motor starting device coin )rising an electromagnet, a switch operate thereby, mechanical means for holding said switch in closed osition, means for opening the circuit of said magnet upon the closure of said switch, a tripping electromagnet for controlling said mechanical means to opensaid switch, and a circuit for said tri ping magnet having a manually controlled swltch and also a switching mechanism automaticallyclosed upon an abnormal increase or decrease, or upon a complete failure of the supply of current to the motor! 3. In a motor starting device, the combi nation with an electromagnet, of a switch operated thereby for connecting the motor to the mains, mechanical means for locking said switch in closed position, means for o ening the circuit of said magnet upon the clbsure of said switch, and electromagnetic means for automatically releasing said switch u' on the failure of the supply of current to t e motor.

' 4. In a motor starting device, the combi nation with electromagnetic switchin mech anism for starting the motor, of. mec anical means for holding said switching mechanism in the running position of the motor, an electromagnet adapted by its energization to release sa1d lockin means, and means for automatically closm the circuit of said electromagnet upon t e failure of the supply of current to the motor.

5. In an automatic motor starter, the combination with electromagnetically o erated switching mechanism for controlling t e flow of current to the motor, of a restoring electromagnet adapted upon its energization to restore said switchin mechanism to its initial position,.and a circuit for said restoring electromagnet, automatically closed upon the failure of the supply of current to the motor.

6. In a motor starting device, the combi nation with electromagnetic switching mechanism for controlling the flow of current to the'motqr, of a restoring electromagnet, and a switch automatically 0 crating to close a local circuitthrough said restoring magnet and the motor armature upon the failure of the supply of current to the motor,'whereby said magnet is energized by the inertia of the revolving armature and restores the switching mechanism to its initial position.

7. Ina motor starting device, the combination with an electromagnet and a switch operated thereby to control the fiow of current to the motor, of mechanical means for locking said switch in the running position of the motor, a restoring electromagnet adapted upon its ener 'zation to release said swltch, and a circuit or said restoring electroma net automatically closed upon the failure 0 the supplynof current to the motor.

8. a motor starting device, the combination with an electromagnet and a switch operated thereby to control the flow of current to the motor armature, of mechanical means for locking said switch in the running position of the motor, and a magnet energized by the inertia of the revolving motor armature upon the failureof the su ply current to the motor, whereby sai locking means is released and the apparatus restored to its initial position.

9. The combination with a motor having a starting resistance included in the circuit of its armature, of a starting device compris mg a manually operated starting switch, electromagnetic switching means operated by the closing of said starting switch to connect the motor to the main line, electromagnetic switching means for cutting out said starting resistance, mechanical means for locking said electromagnetic switches in the running position of the motor, and restoring electroma nets ada ted u on their energization to re ease sai switc es, said restoring electromagnets. having normally open circuits.

10. "The combination with a motor having a starting resistance in its armature circuit, of a motor starting device comprisin a plurahty of solenoids, switches controlled by said solenoids for successively cutting out steps of said resistance, a relay inseries with the armature circuit and controlled by the fluctuations in the motor current for controlling the admission of current to said solenoids and a switch opened by the last acting so enoid for eliminating the consumption of current by said starting device after the operation thereof.

1-1. The combination with a motor having a starting resistance in its armature circuit, of a plurality of solenoids, switches controlled b said solenoids for closing the circuit of t e motor armature and for successively cutting out steps of said resistance, means for opening the circuits of said solenoid upon their operation to close said switches, mechanical means for locking said solenoid switches in closed position, and electromagnetic means both automatically controlled and under the control of the operator for releasing said locking means.

12. In a motor starting device, the combination with a motor having a starting resistance in its armature circuit, of a plurality of resistance solenoids, switches controlled by said solenoids for cutting out steps of said resistance, a master rheostat solenoid, a lever actuated thereby for successively closing) the circuit of said resistance solenoids, a rake coil, brake mechanism operated by said coil for controllin the response of said lever to said master so enoid, a relay in series with the armature circuit and controlled by the fluctuations in the motor current, said relay in turn controlling the energizatlon of said brake coil, mechanical means for hoflding the last operating solenoid switch in closed position, whereby the entire starting resistance is cut out and a switch adapts to be opened by the last acting solenoid and thereby prevent the consumption of current by the starting device after said starti re sistance is cut out, substantially as descri ed.

13. In a motor starting-device, the combination with electromagnetic switches for contiolling the flow of current to the motor, of mechamcal means for locking said switches in the running position of the motor, restoring magnets adapted when energized to release sald switches, a relay in'the motor circuit having an underload and an overload armature operating upon an abnormally weak and abnormally strong current, respectively, to close the circuit of one or more of said restoring magnets.

In'witness whereof, I hereunto subscribe my name this 23 day of September A. D., 1905. i

WILLIAM F. HENDRY.

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