US897713A - Motor-starter. - Google Patents

Description

om 0 9 l l, T.. P E S D E T N E T A P 7. 0 9 1 R. 9. www NRA RAD UTM iRA ...om AMM Mw L P D.. A om 1 ./r .l 9 00 o. N.

5 SHEETS-SHEET 1.

MN Q

,hh bm.

i@ MN.

@Nonna 1g Wi b1 @web No. 897,713. PATBNTBD SEPT. l, 1908.

A. J. BURNS.

MOTOR STARTER.

APPLICATION FILED AUG. 9,1907.

5 SHEETS-SHEET 2.

` Q m2: M

Q l' @u HW E l- L A UQ@ x Iig-3% A A vwenoz www. na/y/J. Bar/ 75,

attoznm m 0 9 1I. LA L D.. u D E T N ...L T .A .P

m. S.T MR um BS 51m Aw M APPLICATION FILED AUG. 9; 1907.

k 5 SHEETS-SHEET 3.

l attkoznu No. f,8.971,71 3.

A. J. BURNS. MOTOR STARTER.

APPLICATION FILED AUG.:9 ,1907.

PATENTE-1D SEPT. l, 1908.

.5 SHEETS-SHEET 4.

TT T w .Q f@ I ,w m Qn mf @i a @Nonnu m 0 9. 1 l, T P E s D E T N E T A D.. 7. o 9. 1 Pu..91 Sum NRA mi Bmm R AOM Mw L D.. D.. A om l .l. 7 9 8 0. N

5 SHEETS-SHEET 5.

uNrrEn sTATEs EATENT oEEroE.

ANTHONY); BURNS, or oswEGo, NEW YORK.;

MOTOR-STARTER.

Specification of LettersPatent.

Patented Sept. 1, 1908.

Application led August 9, 1907. Serial No. 387,939.

/To all whom it may concern."

Be it known that I, ANTHONY J. BURNS, a citizen of the United States, residing at Oswego, in the county of Oswego and State of New York, have invented new and useful Improvements in Motor-Starters, of which the following is a s eciiication.

This invention re ates to a motor starter 4of, the automatic or no voltage release Atype operation of apparatus of the character re ferred to so as to be comparatively easy and inexpensive to manufacture, thoroughly relia-ble and efficient in use, of substantial, du-

1 rable and compactform, and designed to enable the circuit to be either automatically or manually opened.

A further object of the invention is the provision of a motor starting ap aratus including an automatically released ocking dey vice for holding the starting switch in normal running position, in combination with an auxiliary means for opening the circuit between the mains and starting switch in case the latter should fail to return to the initial or open circuit position after the locking device has been released.

A still further obj ect of the invention is to provide -a motor starting apparatus comprising in a unitary structure, a starting switch tendingconstantly to return -to normal osiy tion, an electro-magnetically actuated ocking device which normally holds AAthe starting switch in runnin@` position and is adapted to automatically release the switch when the current'drops to a predetermined point, and van oil immersed switch which is electro-magnetically operated to open the circuit between .the mains and starting switch. 50..

With these general objects in view, and

others as lwill appear as the description proceeds, the invention comprises the various novel features of construction and arrangement of parts which will bemore fully described hereinafter and set forth with particulari-ty the claims appended hereto.

In the accompanying drawings, which illustrate certain of the embodiments of the invention, Figure 1 is a front view of the apparatus. Fig. 2 is a view of the left hand end of the same.

view of a hub of the movable element of the starting switch showing the returning spring therefor. Fig.- 5 is avertical section on line 5 5, Fig. 1. Fig. 6. is a vertical sevction on line 6-6, Fig. 5. Fig. 7 is, a vertical transverse section on line 7-7, Fig. 1. Fig. 8 is a diagrammatic view of the circuits of the a Earatus. Fig. 9 is a detailvview of a mo iedform of an electro-magnetically released lock for the starting switch. l. Similar reference characters are employed Fig. 3 is a section on line 3-3,' Fig. 2. Fig. 4 is a detail sectional to designate corresponding parts throughout the several views.

. Referring to -the drawings, 1 designates a slab of marble or the like forming a supporting plate for the various parts of the apparatus, and secured to the rear side thereof by bolts 2 is a cast iron orother casing 3 which is resistance-containing compartment 5 and a 4switch-containing compartment 6, the former compartment being open at its front and closed by the marble slab 1, and thelatter compartment .being open only at .the top to contain a body of oil for preventing arcing between the blades and contacts of the cutout switch designated generally by A, Figs. 5, 6 and 8, and the top of the compartment 6 is yclosed by a cover 7. y

The motor-starting switch, designated generally by B, is mounted on the supporting plate 1 in front of the compartment 5. This switch comprises one or more groups of condivided by a vertical partition 4, Fig. 6, into a tacts or segments C suitably secured to the marble front plate, and a rotatable element D carrying means for engaging the contacts to complete lthe/circuits between the source of supply and motor and vary the voltage impressed on the motor circuit during the starting operation. Each group of contacts C com rises a row of spaced copper blocks 8 or the ike and a copper segment 9 arranged inwardly with respect to the blocks 8, there being dead contacts 10 and 11 at the end of the row and segment for the brushes to bear -on when the switch is open. The rotatable element Q of the switch 1s composed of a hub member 12 having one or more radial arms 13 for carrying the brush holders 14, there being ico interposed between eahbrush holder and ad- V jacent arm, a block of insulating fiber 15 or the like which is secured to the parts by bolts 16. Formed on the hub member is a crank arm 17 which is rovided with'a knob 18 that serves as a han le to permit the switch to be the front side of the bolt that has aworking fit in the hub and which cooperates with a cap 22 fitted on the bolt and in the hub to provide a bearing on which the hub turns. The cap 22, as shown in Fig. 7, is secured in place by the screw bolt 23 and is prevented from turning by pins 24 extending through the cap and into the front end of the pivot 20. ln the hub 12 is a coiled spring 25 which, as shown in Fig. 5, is anchored on a pivot bolt 2O at the inner end and secured to the hub at the outer end and the spring is so arranged that when the starting switch is in running position, there will be sufficient tension to return the rotatable element of the switch to initial po- 25 sition in the event of a failure of current in the supply system.

The brush-holders 14 are metal castings or the like of hollow rectangular form for receiving blocks of carbon 26 constituting brushes gogthat engage the contact blocks 8 and segments 9 so as to convey current from the blocks to the adjacent segment, as the movable element of the switch is actuated for starting the motor, the blocks being conneeted with the mains of the supply system and the segments with the motor circuit. On each holder 14 are apertured lugs 27 which form bearings for a shaft 28 that carries 4a torsional spring 29. The spring 29 is U- a shaped and has its ends coiled around the shaft 20 and securedV thereto, the U-shaped portion of the spring bearing on a plate 26 on the top of the brush. On the shaft 28 is a worm wheel 30 with which engages a worm 31, Fig. 2, so as to turn the'shaftA 28 for bearing the tension of the spring, the worm gearing serving as a lock for preventing the spring from unwinding after once bein set. The worin-carrying shaft has a knur ed head or enlargement 32 serving as a hand-hold whereby the worm can be actuated by hand. `On each brush-holder is a bridging contact 33 composed of a plurality of metal lamina; 34 that are adapted to bear at their ends on the terminals 35 and 36 for the conductors leading from the supply mains and leading to the motor. As shown in Fig. 7, the terminals'35 and 36 have threaded studs 37 that extend through openings in the marble slab 1 and have nuts 38 for receiving the cable or conductor tips The contact blocks and segments 8 and 9 are secured to the marble slab by through bolts 40, Fig. 7. The bolts of the Contact blocks 8 are provided with coupling tips 41 of the inductive resistances of the motor starter, the resistances being of any approved construction, and designated by R in Fig. 8. Behind the plate 1 are connections between the terminals 35 and 36 and adjacent contact block 8 and segment 9, respectively, which connections are indicated at 42 and 43, Fig. 8.

In order to hold the motor starter in running position, as shown in Figs. 1 and 8, a locking device, designated generally by E, is provided. This device consists oi: a slide 43 disposed at the front of the supporting plate 1 and having one end connected by a pin 44 with the crank arm 17, which has a slot 45 for receiving said pin. On the arms 17 are oppositely varranged set screws 46 that cX- tend into the slot 45 and engage the pin 44, so as to adjust the latter. The member 43 operates as a catch that engages a pivoted detent or lever 47 fulcrumed at 48 on one end of the casing 3, as shown in Fig. 2, and the catch 2 has a hooked-shaped extension 49 that engages over an anti-friction roller 5() secured on the front end of the member 47, which member projects through a slot 5l in the plate 1, so as to have vertical movement. On the supporting plate 1 is a horizontal guide 52 on which moves back and forth the outer section 53 of the member' 43. The guide 52 is composed' of s )aeed rails, as shown in Fig. 2, and the member 53 is held in sliding engagement by a headed screw 54 that has its shank disposed between the rail and its head engaging the under side of the latter. Between the inner and outer seetions of the member 43 is a hinge joint 55. The detent 47 is held in locking position by means of an adjustable spring 56 which is connected with the detent and with the side of the casing 3. On the oscillating member or detent 47 is mounted an anti-friction roller 57 that is adapted to bear on the side of thc casing and aord a support for the detent, and under the latter is arranged an abutment 58 on which the detent rests when the same is in unlocked position. Any suitable means may be em loyed for throwing the detent when the vo tage of the supply system drops to a predetermined minimum. I For this purpose, a weight or equivalent means majV be employed and, as shown in Fig. 2, the rear end oi" the detent is located in the path ol" a weight 59 that is guided in a vertical way 60.

secured to the outside of the casing 3. This weight has a rubber or other bul'ling device 61 secured to the bottom thereof so as to cushion the shock roduced by the dropping of the weight on tiie detent. The weight is su ported in raised position by a trip lever 62 fulibrumed at 63 and provided with an armature 64 associated with an electro-magnet 65. The upper end of the lever is arranged to cngage under an anti-friction roller 66 carried by the weight 59. The lever' is held in normal position by the electro-magnet 65 being ening ergized, and the lever is moved out of Aengagement with the roller v6.6 by an adjustable s ring 67 that is adapted to act when the e cetro-magnet becomes denergized. The electro-magnet is connected in circuit at any suitable point so as to become denergized when the voltage of the supply system becomes zero or any other predetermined minimum. As soon as the weight dro s, the

arts of the locking device are move to u'nocking position so as to permit the movable element of the starting switch to return to open circuit position under the tension ofthe s ring 25. After the apparatus has been tiirown out of commission, the weight has to be raised to the top of the guideway 60 and for this purpose, the weight has a hand-hold or knob 68 that projects out of the inclosing casing or housing 69 for the apparatus, as shown in Fig. 3. The lever 62 has a cam surface 70 with which the roller 66 engages when the weight is lifted, it being understood that the weight is lifted after the electro-magnet 65 is energized and the lever 62 is in its lockosition.

-T e cut-out switch A, which is connected between the supply mains and the motorstarting switch, 1s, in the present instance, of the two-blade type, the blades 71 of which are pivoted at their upper ends on blocks 72, as shown in Figs. 5. and 6. The lower ends of the blades are adapted to engage the spring contacts or aws 73. The two blades are rigidly connected together by a cross-bar 74 of insulation, there being a frame 75 on the `center of the bar to. which is pivoted a llink 76.

'the front of the casing 3 and slab l and is I This link extends through a slot 77 in connectedwith an operating lever. The lower endgof the lever is pivoted at.79 on a bracket 80 extending forwardly from the front side of the slab 1, and by this construc* tion the switch can be opened from the front of the apparatus. Disposedwithin the oilcontaining compartment 5 is an electro-magnet 81 having its coils 82 supported on the front wall of the compartment 5 at a point directly in front of the switch A, and the armature 83 is connected with the link 76 sol as to open the switch when the electro-magnet is energized. The armature 83l is preferably a bar that extends through an opening 84 in the link 76 and has its ends bent laterl ally to extend into thecoils 82. The electromagnet is provided with a core 85 which is also a bar of V`soft iron bentat its ends to ex- -tend into the hollow of the electro-magnet coils. The terminals V7 2 and 73 of the switch A are connected respectively with the supply mains and conductors leadin to the motor, and the connections are ma e by means of the usual tips 86 that are bolted or otherwise secured to the switch terminals', as shown in Figs. 5 and 6. The electro-magnet 81 is connected across the terminals 73 of the switch and the energizing of the electro-magnet isA controlled by means of a circuit-closer F which is clearly shown in Figs. 2 and 8. This circuit closer depends for its operation upon the dropping of the weight 59 and comprises spaced terminals 88 and a bridging contact This contact is secured to the bottom of a weight 90 that is guided vertically in a guide 91, the parts of the circuit closer 'being mounted on a base-plate 92 of marble, slate or the like, so as to insulate the same from the cast iron casing 3. When the lock-releasing weight 59 is in raised position, the bridging contact 89 of the circuit-closer F is out of engagement -With the terminals 88, this being accomplished by means 'of a block of insulation 93 mounted on the weight 59. As soon as the weight 59 drops, the circuit closer will close the circuit, including the electro magnet that controls the oil im- .mersed switch so as to thereby open the latter. On one of blades 71 is a secondary blade 94, Figs. 6 and 8, that engages s ring jaws 95 that are connected in circuit with the lock-releasing electro-magnet 65, so that upon the closing of the oil-immersed switch, the said electro-magnet will be immediately energized. In the compartment 6y is contained a body of oil or other suitable liquid which is employed'for extinguishing the arcs produced by the o ening of the switch A, es-

ecially when high voltages are employed. t is .to be understood, however, that any other suitable quick brake or arc-extinguishing switch maybe used, if required. The various parts of the oil-immersed cut-out switch are mounted on a supporting plate 96 of marble, slate or the like that is bolted or otherwise suitably secured to the back wall of the compartment 6.

lReferring now to Fig. 8, the various circuits will be described in connection with-the method of operation. In the present instance, an apparatus is shown designed for use in connection with a three-phase alten nating current system, but it is to be understood that the apparatus can be used in other systems. a, b and c designate the mains of the supply system, and connected therewith are the lead wires d, e and f, there being suitable safety devices. such as fuses g connected between the leads and mains so as to protect the motor and starting apparatus therefor.V The leads d, e and f are each'con-nected with the terminals 35 ofthe starter and the blades 7 l of the oil-immersed switch are included in the leads d and e,` and leading from the ter-minals 36 are the wires h, 'i and that connect with the motor (not shown); Bridged lacross any two of the mains are the wires k and l that comprise the circuit including the lock-releasingelectro-magnet 65, and in the of the switch A, and from the electro-magnet tothe circuit-closer F extends a conductor m, the said conductor connecting with one of the terminals of the circuit closer. The opposite terminal 88 is connected by a conductor n with the terminal 36 of one of the sections of the motor starter. The circuit is completed through the bridging contact 33, terminal 35, and conductor 'o leading from the said terminal 35 to the terminal 73 for the left hand blade of the switch A.

When the parts of the apparatus are set, as shown in Figs.` 1 and 8, the motor is operated under normal conditions. Current passes directly between the mains ofthe supply system to the motor through the leads d, e and f, terminals 35, brushes 26 and bridging contacts 34 in multiple, terminals 36, and conductors 7L, .t and j. It will thus be seen that the inductive resistances R or other impedance devices are entirely cut out of circuit. The carbon brushes bear on the last contact blocks 8 and Contact segments 9 and current passes through the brushes by way of connections 42 and 43. As long as the switch A is closed, current passes constantly through the electro-magnet that controls the releasing of the locking device, and the circuit includes the main C, conductor l, auxiliary cut-out switch 94, electro-magnet 65, conductor 7c, and main Since current is constantly passing through this electro-magnet,

the devlce controlled thereby is so designed that comparatively little power is consumed in maintaining the electro-magnet energized. It will be observed that the circuit closer F is open while the motor starter is in running position and is ready to close as soon vas the voltage of the mains drops to a suiiiciently low point. When the rotatable element D of the motor starter is in the position shown, the returning spring 25 thereof is under tension and so held by the roller 50 of the detent 47, Figs. l and 2, engaging in front of the projection 49 of the catch 43. As soon as the voltage in the mains drops to a predetermined minimum, the electro-ma et 65 becomes denergized so as to ena le the ree tractile s ring 67, Figs. 2 and 8, to draw the latch or ilaver 62 from under the roller 66 on the weight 59. The weight is thus permitted to drop so as to strike the detent or member 47 and throw the outer end thereof upwardly and out of the path of the projection 49, Fig. 1. This action releases the rotatable element of the motor starter so that it can be turnedto initial or open circuit position under the action of the spring 25. Simultaneously with the dropping of. the Weight 59, the circuit closer F is actuated to complete the circuit that includes the electro-magnet 81, so as to cause the oil-immersed switch A to be automatically opened and thereby completely cut the motor starter out of circuit and rotect the motor upon the restoration of voltage in the mains in the event of the rotatable element .of the motor starter failing to return to open circuit position. l/Vhen it is desired to cut the motor out of service, the o erating lever 78 of theqcut-out switch A is pulled forwardly so as to open the said switch, and by this operation, themauxiliary cut-out switch 94 is opened so a`s"\ .to denergize the electromagnet 65, with t`h"e-`result that the weight 95 releases the locking device E and permits the' rotatable element of the motor starter to automatically return to normal position.

In starting the motor, the operating lever 78 of the cut-out switch A is iirst pushed backwardly lso as to close the switch. This Icloses the circuit that contains the electromagnet 65 so that the lever or catch 62 will be thrown to locking position by the electromagnet, it being understood that the weight 59 is raised to its normal position after the switch A is closed so as to cause the circuit closer F to open before the current is thrown on the motor. The operator then turns the operating crank 17 in a clockwise direction so as to move the brushes 26 off the dead contacts 10 and 11, and as soon as the brushes reach the first contacts 8, current will flow to the motor through all of the sections of the inductive resistances R and as the movementis continued, the resistances are cut out step by step so as to gradually increase the voltage until the last contacts 8 are reached, when all of the resistances are cut out and full voltage impressed upon the motor. Dui'- ing the movement of the operating crank 17, the member 53 slides on the guide 52 and the inclined surface of the projection 49 engages the anti-friction roller 50 and causes the detent 47 to be raised against thetension of the spring 56. As soon as the projection 49 moves past the roller 50, the spring 56 will cause the said roller to engage behind the pro'ection and automatically lock the rotatable element of the starting switch in running position.

In the modified form of locking device shown in Fig.9, the parts are so designed as to dispense with the weight. The detent 47 is fulcrumed on the side of the casing in the usual manner and the front arm is so proportioned that its own weight will maintain the detent in locking osition. The detent is raised by means o a helical contractile spring 100 that has one end secured to an adjusta le plate 101 and the other end secured to a member 102 in the form of a screw, the threads 103 of which serve to engage the convolutions of the spring for attaching the latter to the member. Between the member '102 and detent 47 are flexible elements 104, which permit the front end of the detent to be raised by hand when it isldesired to open the motor starting switch without throwing the cut-out switch A open. The spring 100 1s held in stretched condition by a catch or lever 105 that is fulcrumed 'on the side of the casing and carries an armature 106 associated lwith the electro-magnet 107. This electro= Ythe electro -magnet of the oil immersed switch, as will be readily understood. When the voltage in the mains falls, the catch 105 is permitted to iy back so as to allow the spring 100 to lift the -front end of the detent 47 out ofoperative relation with the other par-ts of the locking device. At the same time, the circuit closer F will complete the circuit containing the electro-magnet that controls the cut-out switch. It is obvious that other modifications may be employed wherein the weight is dispensed with.

From the foregoing description, Ataken in connection with the accompanying drawings, the advantages ofthe construction and ofthe method of operation will 'be readily apparent to those skil ed in the art to which the invention appertains, and which I have described the principle of operation of the invention, together with the apparatus which I now consider to be the best embodiment thereof, I desire ,to have it understood that the apparatus shown is merely illustrative and that such changes may be made when desired, as are within the scope of the claims.

Having thus described the invention, what I claim is 1. The combination of a motor starting vswitch including a movable contact member and means tending to hold the same at open circuit position, a locking device -for holding the element in running position, an automatically actuated `cut-out switch, an electro magnet normally in open circuit for opening the cut-out switch .and means responsive to a drop in voltage for controlling the operation of the locking device' and closing the circuit of the said electro magnet.

2. The combination of a motor starter including a biased contact-carrying arm, with, an automatically actuated cut-out switch, a locking device for holding'thearm in running position, a normal open circuit closer connected 4in circuit with the 4cut-out switch,

and means responsive -to changes in voltage for releasing the locking device to permit the arm to move to open circuit position and for closing the said circuit closer.

3. The combination of a no-voltage release motor starter,with an automatically-actuated open circuit closer for controlling the opening of thegcut-out switch, and means responsive to nii-:voltage i associated with the conditions 4Jfor iirst closing the said closer and subsequently opening the motor starter.

4. The combination of a no-voltage release motor starter, with a cut-out switch disposed between the starter and source of current, a locking device for holding the movable'element of the starter in running position, a normally open ci-rcuit closer connected in circuit With the cut-out switch, and an electromagneti-cally controlled means sensitive to an abnormal drop involtage for ermitting -the said circuit closer to close and) the movable element of the' starter to move to open circuit position. K

5. The combination of a motor starter including a movable contact member adapted Vto automatically return to open circuitposition, a locking device Jfor holding` the element in closed ycircuit position, a weight arranged to release the locking device, an .elec-tromagnetically operated cut-out switch, and means sensitive to no-voltage conditions for permitting the weight to act and for closing the circuit including the electro-magnet of the cut-out switch.

6. The combination of a motor starter including a movable ycontact element adapted to'automatically return to o )en circuit position, a locking device for hol( ing the element in closed circuit position, a gravity-acting means for releasing the locking device, means sensitive to no-voltage conditions for pervmitting lthe said means to act, a'n automatic cut-out switch, and a second gravit -acting means depending upon the 'irst for ringing the cut-out switch into operation.

7 .Y The combination of a motor starter including a movable contact element adapted to Vautomatically return to o en circuit position, a locking device for hol ing the element in closed circuit position, a gravity-acting means for releasing the locking device, an electro-magnetically o erated cut-out switch, a circuit closer normal y open and adapted` to close -by gravity when the said means operates, and means sensitive tovabnormal voltage conditions for permitting the gravity` acting means to operate. N

8.- Thefcombination of a motor starter including a movable contactelement adapted to automatically return to open circuit position, a locking device for holding the element in closed circuit position, a cut-out s witch, an electro-magnet for opening'the switch, a circuit closer normally open and adapted when closed to energize the electro-magnet, and electro-magnetically operated means for releasing the locking device, and a switch cut-out switch for opening the circuit of the electro-magnet ofthe lock-releasing means. 9. The combination of a motor starter including a movable contact 'element adapted to automatically return to open circuit position, a locking device for holding the element in closed circuit position, a cut-out switch, means for automatically opening the switch, and a mechanism sensitive to voltage conditions for releasing the locking device and for bringing the said means into operation.

10. The combination of a no-voltage release motor starter, with an automatically operated cut-out switch adapted to operate under no-voltage conditions, an electro magnet normally in open circuit and arranged to open the switch, and means for closing the circuit of the electro magnet automatically.

11. The combination of a motor starter, with an oil-iinincrsed cut-out switch associatcd therewith, and a lever for manually opening or closing the switch, a link between the lever and switch, and an electro magnet having its core connected with the link for opening the switch under 11o-voltage condi tions.

12. The combination of a motor starter, with an loil-immersed cut-out switch associated therewith, an electro-magnet for opening the switch, a normally open circuit closer controlling the circuit of the electro-magnet, and means operated by a fall in voltage for permitting the circuit-closer to complete the circuit.

13. The combination of a motor starter, with an electro-magnetically operated cutout switch, a normally energized electromagnet, a switch carried by the cut-out switch for opening and closing the circuit of the electro-magnet, a circuit closer controlling the operation of the cut-out switch, and means under the control of the electro-mag net for permitting the circuit closer to complete the circuit when the electromagnet becomes denergized.

14. The combination of a novoltage release motor starter, a cut-out switch, elec- -'trically operated means for opening the switch, a gravity acting circuit closer for said means, and a device responsive to a dro in voltage for permitting the said circuit closer to close.

15. The combination of a no-voltage release motor starter, a cut-out switch, an electro-magnetically operated means for opening the switch, a manual means for opening or closing the switch, and means responsive to a drop in voltage for operating the electromagnetically operated switch opening means.

16. The combination of a motor starter including a rotary element, and means for re turning the element to open circuit position, with a locking in closed circuit position, said device com* prising a catch member,l a detent for holding device for holding the element the catch member in normal operating position, and a suddenly acting motor normally separated from and arranged to strike a blow on the detent -lor moving the latter out of engagement with the catch, said detent being capable of being manually released for permitting the element to return to open circuit position.

17. rlhe combination of a motor starter including a rotary element, and means for returning the element to o en circuit position, with alocking device ioriliolding the element in closed circuit position, said device comprising a member composed of hingedl y connected parts, means for connecting one of the parts with the said element, a guide for the other' part, a detent adapted to engage the member to prevent the element from moving to open circuit position, and means for operating the detent to release the same from the member.

18.- The combination of a supporting structure containing a li uid holding` compartment, a cut-out switclh mounted iii-the said compartment, a motor starter mounted on the structure and including an arm, a fixed guide, a member slidably mounted on the guide, a connection between the member and arm, a spring tending to move the arm in a direction to open the motor starter, :ly locking device arranged to engage the said member for holding thestarter in normal position, and means operated at a drop ol voltage to a predetermined point lor permitting the motor starter and cut-ont switch to open.

19. The combination of a casing divided into separate compartments for containing resistance units and oil, a cut-out switch in the compartment containing the oil, stationary contacts, a movable contact element cooperating with the stationary contacts, a spring for moving the element in one direction, a locking device arranged outside the casing for holding the element in running position, and means for releasing the locking device and opening the switch.

20. The combination of a motor starter including a spring-actuated contact element, an arm connected therewith, a locking device for holding the element in closed circuit position, and an adjustable connection between the arm and locking device.

In testimony whereof, I affix my signature in presence of two witnesses.

ANTHONY J. BURNS.

Images