US982913A - Apparatus for controlling electric motors. - Google Patents

Description

G, H. WHITTINGHAM. APPARATUS FOR CONTROLLING ELEOTRIO MOTORS.

APPLICATION YILED KAY 31. 1910.

Patented Jan. 31, 1911.

3 SHEETS-SHEET 1.

awuwwlfoz G. H. WHITTIHGHAM. APPARATUS FOR CONTROLLING ELBGTBIG mo'rons.

APPLICATION FILED HAY 31 1910. I 982,9 1 3, Patented Jan. 31. 1911.

a gums-51mm- 2.

G. H. WHITTINGHAM. APPARATUS FOR CONTROLLING ELEGTRIC MOTOBS. APPLIOATIOH FILED In 31. 1910.

982,9 1 3; Patented" Jam 31, 1911.

3 SEBETB-BHEET 3.

fitter/1101 1 5 OF PIKESVILLE, MARYLAND, ASSIGNOR TO MONITOR OF BALTIMORE CITY, A CORPORATION OF MARYLAND.

GEORGE H. WHITTINGIIAM,

MANUFACTURING COMPANY APPARATUS FOR CONTROLLING ELECTRIC MOTORS.

Specification of Letters Patent. -Pa,tented Jan. 31, 1911.

Application filed May 31, 19.10. Serial No. 564,164.

To all whom "it may concern:

Be it known that I, Gnonon H. Wnrrrmo- HAM, a citizen of the United States, resid ing at Pikesville, in the county of Baltimore and State of 'Maryland, have invented certain new and useful Improvements in Apparatus for Controlling Electric Motors, of which the following is a specification.

This invention comprises improvements in controlling devices for 'electric motors which must be operated at different speeds and controlled from one or a number of points.

In operating certain classes of machinery, such as large printing presses, it is desirable to provide for a wide range of speedsbetween the maximum and minimum, and also to provide means whereby the speed may be varied, or the motor stopped and started, from different points around the press, and also to provide means whereby if the motor is stopped by a switch located at one point, it cannot be started by a switch located at any other point, until the person operating the first mentioned switch is willing that the motor should start. The apparatus of my invention is designed to fulfil these requirements.

In the accompanying drawing, whi'c illustrates my invention, Figure 1 is a diagrammatic illustration of the elements. of the apparatus, and their electrical connections'; Fig. 2 is a side view of the current controlled speed regulating devices, "the solenoid being shown in central" section; Fig. 3 is a front view ofthe devices shown in Fig, 2; Fig. 4 is a'section on' the line 47- 1 of Fig; 3; Fig. 5 is a side View, on a small scale, of a modification showing the brake magnetapplied to the solenoid core. Fig. 6 is a diagrammatic view, the same as Fig. 1, except as to the brake magnet and solenoid circuit connections. A a

,Referring to Fig. l of the drawing, land 2 indicate the supply "wires-or leads connected to the terminals of the supply circuit switch 3; A indicates 'a switch for making and breaking connection between the supply wire 2 and the circuits of themotor M; 13 indicates a rhcostat or regulating re sistance in the armature circuit; C indicates a resistance in the shunt field circuit; D' in dicates an adjustable speed regulatingv device and E, E indicate panels having manually controlled switches thereon for effecting the desired changes in speed of the motor and for stopping and starting the same.

The details of construction of the speed regulating apparatus D are shown in Figs. 2, 3 and 4:, wherein at indicates a solenoid having a high resistance winding 4, contained within a suitable iron-clad casing 5 and adapted toactuate a core 6 from which is suspended a frame 7 having a series of hinged contact fingers, 8 8 8, etc., adapted to engage contact points 9*, 9*, 9, etc'., respectively, which are held in suitable metal blocks 10 and adjusted to successively greater heights by adj ustin screws 11. The frame 7 comprises a triangu ar plate 7 which is secured to the core 6, and two- T-shaped end plates 7 the several plates being connected by rods 7", 7 and 7". The contact fingers 8, as shown best in Fig. 4:, are pivotally connected to the rod 7 and are adapted to rest upon the rod?" when the frame is in its uppermost position. As the framedescends it will be seen that the fin ers will engage the contacts in succession, rom left to'right in Fig. .3, and finally, when the frame is in its lowermost position, shown in Fig. 3, all .of the fingers will engage .con' tacts and rest thereon instead of upon the bar 7 On the other hand, as the solenoid core and frame 7 move upward, the bar 7 will raise the fin ers, in succession, from right to left in F g. 3, out of engagement with the stationary contacts. If the core and frame be stopped at any position between the lowest and highest positions of the core, certain of the fingers will engage the stationary contacts while other fingers, at the right in Fig. 3, will be held out of engagement therewith. In the drawing ten fingers and stationary contacts are shown, for the purpose of illustration, but these may .be multiplied to any desired extent according to the graduations in speed required. The horizontal part of the plates 7 abut against the slate switch board 12, so as to prevent the frame from turning and to maintain the fingers in alinement with the netic material connects the upper end of the core 6 with a yoke 14 in which is pivoted, upon a pin 15, a lever'16 connected at one stationary contacts. A rod 13 of non-magend with a plunger 17 of-a dash pot 18 and at the other end to a stationary pivot pin 19. 'Another yoke 20 upon the pin 15, carries a flat iron rod or bar 21, which rests against the pole pieces. 22 and 23 of a brake ma net (5.

n the diagram Fig. 1, the contact fingers 8, 8", etc, are represented by a short circuiting bar Send the stationary contacts are represented by metal strips of successively greater lengths with which the short circuiting bar is adapted to engage by sliding contact, while the dash pot is shown above the solenoid and the brake magnet engages the iron bar 21, which is here also represented as the dash pot plunger.

In Fig. 1 of the drawing the apparatus is shown with the circuit connections com-- pleted for the operation of the motor, the short circuiting bar 8 being shown, in full lines, in position to cut out all of the armature resistance and include only a portion of the field resistance, the dotted lines indicating the normal position of the bar. The switch A, for completing and interrupting the circuit through the motor, comprises an 'armature 24 pivoted at its central portion to the central pole piece 25 of an E-shaped 'magnet 26 and having an armature 27 adapted to engage, alternately, the end pole pieces 28 and 29 of the electromagnet. The end pole pieces 28 and. 29 are surrounded by windings, as shown, which are permanently energized, when the switch 3 is closed, through acircuit indicated by the arrow 0, and which may be traced as follows: from the supply wire 2 to astationary switch terminal 30, thence through a resistance 31, and wires 32 and 33, to the coil surrounding the pole piece 28, thence through wire 34 to the coil surrounding the pole piece 29, thence through wire 35 to wire 36 and thence to the opposite supply. wire 1. Upon each of the panels E and E is arranged a switch F for short circuiting either one of the coils upon the pole piece 28 and 29, and when the coil of one pole piece is short circuite'd the other pol piece will attract the-armature 27, so that the switch arm 24 may bemoved to open or closed position by turning the switch F. Thus, the lever 37 on the panel E is connected by conductor 38 to the wire 34 extending between the coils on the pole pieces 28 and 29 and this lever when swung in one direction is adapted to engage a contact 39 connected to the conductors 32 and 33, and it will be obvious that when the arm 37 is in engagement with the contact 39 the coil on the pole piece 28 will be shunted,-

the-c'urrent passing through the contact 39 and arm 37 and wire 38 to the conductor 34 instead of passing through the conductor 33 to said coil, and the pole piece 29 will then attract the armature 27 and rock the switch ,to move the arm 24, out of engagement with the supply terminal 30. So long as the switch arm 37 on one panel is in engagement with the contact 39, the coil surrounding the pole piece 28 will remain dead and the switch A cannot be closed by the operation of the switch F on any other panel. To rock the switch A in the opposite direction, to close the connection to the supply circuit, the arm 37 is moved into engagement with the contact 40, which results in short circuiting the coil surr unding the pole piece 29, leaving the coil 0 the pole piece 28 active, and the latter pole piece attracts and holds the armature on the switch arm 24. The short circuit for the coils surrounding the pole piece 29 extends from the conductor 34L through the arm 37 and contact 40 to conductor 41 and thence to a contact 43 which is normally engaged by the short circuiting bar 8, thence through said bar, and conductor 36, which is grounded upon the bar, to the conductor 35. This short circuit, for starting the motor, can only be closed when the contact bar 8 is in its lowermost position, engaging the contact 43, in which position, as will be hereinafter explained, the full resistance is in the armature circuit.-

When the switch arm 37 is moved intoengagement with the contact 39, to stop the motor, the arm will remain in frictional engagement with said contact until manually removed, and, therefore, the person who 'suming the bar 8 to be in its lowermost position), and it is necessary to avoid a permanent or continued short circuit of the coil surrounding the pole piece 29, so that themotor may, when running, be stopped at any time from any panel. Therefore, a spring plunger 4A is provided, which automatically moves the arm 37 away from the contact 40 as soon as the pressure .of the hand is relieved from said arm, and thus, after the coil surrounding the pole piece 29 has been temporarily short circuited, this short circuit will be interrupted automatically by the spring pressed plunger 44 which moves the arm 37 away from the contact 40. It will be understood that although the pole'piece 29 thus becomes energized after the interruption of the shunt around its coils, it will not operate the switch arm 24 because the armature 27 is then in engagement with the other active pole piece 28 of the electro connected together by the conductor 32; the

switch arms 37 are connected together by 54 through a conductor o, 1n which is interposed a brake resistance 56, to-the conductor conductor 45 and the contacts 40 are connected together by conductor 46 so that each switch F, on each panel, operates to open and close the same shunt circuit connections to stop and start the motor.

The armature circuit extends from the 48, and when the switch arm 24 moves out of engagement with the supply terminal 30, it engages the stationary contact 54aand thereby closes the dynamic brake circuit which operates'to stop the motor, in a well known manner.

When the switch arm 24 is movedto connect the motor with the supply circuit it 7 also closes two other circuits, through a con-Y tact 24? on said arm and a stationary contact 57. One of these circuits, indicated by the arrows p, extends through the brake magnet dand the controlling solenoid d, in series, while the other circuit. indicated by the arrows (1. extends through the coils of a series of relays s, 8, s and 8 which operate to control the resistance in the armature circuit.

The circuit p may be traced'as follows: from the contact 57, through wire 58, high resistance coil 59, wire 60, coils of magnet d,

21, or which may engage button switch being connected by a wire 63,-

wire 61, coils of solenoid d' and wire 62 to the supply wire 1. \Vhen the switch 24 is closed, therefore, the brake magnet and solenoid are connected in series, across "the line, with an interposed resistance 59, and normally the solenoid tends to lift its core, but movement of the core is prevented by the brake magnet (l which engages'the iron bar the core of the solenoid as shown in 1 5. The closing of the supply switch 24, therefore, by the operation of the switch F, does not cause the upward movement of the solenoid core and contact bar 8, for the reason that the brake magnet is energized simultaneously with the closing of the circuit. To permit the solenoid to move the bar 8 upward, the brake magnet is short circuited by a push button switch G, one terminal of said push to the wire 60. leading to one end of the brake magnet coil, and the other terminal of said push button switch being connected by a wire 64 and wire 65 to the wire 61 which extends between, and the solenoid. By closing the push butblttlic magnet will be shortcircuited through the conductors (33, (i l and 65 and said switch, and as long as the push button switch is closed the solenoid core will move upward, retarded by the dash pot, until the core reaches the upper limit of its movement. Nhen the push button is released, the brake magnet immediately becomes energized andholds the core and contact bar in the position to which it was carried while the brake magnet was deenergi' zed. ,To permit the solenoid core and the contact bar 8 to descend, provision is made for short circuiting both the brake magnet and the solenoid through a push button "H, one of wh ch is provided on each panel. As shown the push button ll on the panel E has one terminal M connected to the wire 63 and the otherterminal connected to a wire 66 which leads to the wire (32 and thence to the supply wire 1.

Upon closing the push button H on the panel E, the current will flow from conductor 63, the push button H and wire 66 to the wire 62, instead of flowing through the brake magnet and solenoid, and, hence, the magnet and solenoid will be de'einergized and the so: lenoid core and contact bar will fall by gravity, retarded by the dash pot. When the push button H is released the solenoid and brake magnet will become instantly energized and the magnet will hold the core and contact bar in the positions to which they were carried while the button was depressed. The corresponding terminals of the push buttons G and H on the several panels are connected together so as to operate in the same way. Thus the wire 63,. as

. shown in the drawing, connects the adjacent terminals of the push buttons G and H on the panels E and E and the outer terminals of the push buttons G on the different panels are connected by the conductors 64 and 64" while the outer terminals of the buttons H are connected by a conductor 66.

The circuit q through the relays of the rheostat B is traced as follows: from the contact 57 through conductor 67 to a resistance 68, thence through the coils 69,of the relays s'-s inclusive, in series, thence through wire 70 to the wire 50, thence through wire 36 to the supply wire 1. The

cores 71 of therelays are normally in their lowermost positions, and are connected, as shown at 72, to the conductor 7 O, and they are provided at their upper ends with con tacts73, adapted to engage stationary contacts 74, when the cores are moved into their uppermost positions, shown in Fig. 1. These contacts 74 are connected to successsive points in the armature resistance 49.

.- Stationary contacts 75, 76, 77, 78 on the controller are connected by wires 84, 85, 86 and the brake magnet 87, respectively, to the circuit (1, the wire 84 being connected between the high resistance 65 ton switch G, it will be evident that the 68 and the windings of the relay .9, and the lays, the arrangement being such that when the bar 8 is in its lowermost position, shown in dotted lines, the current in the circuit 9,

instead of flowing through the coils of the relays, will flow from the wire 67 and conductor 84 to the contact 7 5, thence to the bar 8 and to the conductor 36, grounded thereon, and thence to the supply wire 1. All of the relays will thus be shunted and the contacts 7.3, being outof engagement with the contacts74, the armature resistance 49 will all be included in series with the armature. If the bar 8 is moved upward off of the contact 7 5 but left in engagement with the contact 7 6, the current in the circuit Q will flow through the resistance 68, the coils of the relay a, conductor 85 and contact 76, to the bar 8. and thence through conductor 36 to the wire 1. The relay 8 will then'lift its core and close the connection between itsof the bar 8 will break the connection with the contact 76, and this will open the shunt around the next relay -.9 and cause said relay to liftits core and cut out another section of starting resistance. The current in the relay circuit 9 will then flow, from the wire 67, throughthe resistance coil 68 and through the coils of the relays s and s, in series, and thence through the wire 86, and contact 77, to the bar 8 and thence to conductors'36 and 1. Similarly when the bar 8 moves upward off of the contact 77 the shunt around the relay 8 will be broken, and said relay will lift its core and cut out another section of starting resistance, and the current in the relay circuit will then flow through the resistance 68 and through the coils of the rela s s s and s in seriesto the wire 87 and contact 78, and thence out through the bar 8 and conductor 36 to the supply wire 1. A further upward movement of the bar 8 will break the connection between said bar and the. contact 78 and thereby include the coils of the relay .9 in

.series with the coils of the other relays and circuits around the field resistance-53, as the bar leaves the successive contacts 7983, in?? elusive. The downward movement-of the bar 8'will first short circuit the sections of the field resistance, in succession and" then bridge the shunts around the relays in sucesaeie cession, and thus cause the gradual introduction of the field and armature resistance.

'duction in the quantity of current flowing and to give each relay the same strength, the relays in succession are wound with wires of greater lengths and smaller diameters, the arrangement being such that each will receive and operate with the same number of watts. An important feature of this arrangement for including and excluding the armature resistance is the absence of sparking between the contact making bar 8, and the. several contacts which it engages. It will be noted that this bar merely opens and closes the shunt circuits around the'relays, to introduce and cut out the armature resistance, and the difierences of potential at the terminals of the relay coils are not sufficient to cause arcs to form between the stationary contacts 75-7 8 and the bar 8; It

is. immaterial, therefore, whether the .bar, after leaving a contact remains close to itor is moved some distance from it, as no injurious effect can result. Hence it is not necessary to stop the bar at any definite point with respect to the contact which it engages and if the push button H is released immediately after the bar 8 passes from the end of a contact, the brake magnet will hold the bar in that position withoutany danger of an are being formed between the bar and the contact, no matter. how closely together they may remain. By this arrangement a large number of contacts may be employed, say twenty or thirty, if desired, and they may be set so that in engaging and disen ga ging" the entire series of contacts the movement of the bar need not be more than say five-eighths of an inch. This is important also because the controlling solenoid may be made comparatively small and will operate with a smaller consumption of currentthan if the solenoid were required to move its core through a long distance.

It will be seen, by comparing Fig. 1 with Figs. 2, 3.and 4 of the drawing, that the fingers 8*, 8", 8, etc.,, cooperating with the contacts 9}, 9 9, etc., will serve the function of the short circuitin bar 8'but avoid the sliding ontact which is not so desirable as the butt In ope a, switches F being-:5 in their neutral positions, the motor may be started, stoppechor controlled in its speed from any of the switch panels E, E, etc., of which there may be any desired number,' having the corretacts made by the fingers.

Witch arms 37 of the 40 again started, from auotherpanel. When sponding switch terminals thereon connected together.. Normally the fingers 8 8", 8, etc., rest upon all of the stationary contacts 9, 9', 9, etc., this position being indicated in the diagramby the dotted position of the bu-1. 8 which engages the contact 43 and the contacts '(5 to 83, inclusive. The main switch arm 24 is normally-out of engage ment with the supply contactSO and in engagement with the contact 54 ofthe dynamic brake circuit. Tostart the motor, the switch 3 being closed, an operator at one of the panels E moves the switch arm 37 of the switch. F into engagement with the contact 40 and thus short circuits the coil on the pole piece 29 of the electromagnet'switch A and the opposite pole 28 attracts the armature on the switch arm 24 and thereby closes the circuit through themotor and through the entire armature resistance, the field resistance being bridged by the bar 8. When the operator releases the hand pressure from-the arm 37, the spring plunger 44: immediately moves said arm out of engagement with the contact sothat thecoil surrounding the pole piece 29 Wlll become again energized and ab e to attract the armature on the switch arm 24: if some one should swing the arm 37 r of the switch F into engagement with the contact 39 ,to short circuit the coil on the pole piece 28 to stop the motor. If the arm 37 is moved into engagement with the-arm 39, to step the motor, it remains I frictionally in engagement with said contact.

until purposely removed so that no one at another panel may start the motor. This protects the operator who stops the motor,

and who may desire to work upon the print-' ing press or other machine, from injury which might be caused if the motor could be and all of the field resistance out of circuit,

unless the push button G, on one of the panels, is de ressed to short circuit the brake magnet. I it is desired to increase the speed of the motor, a button G is depressed, denergizing the brake magnet, and the solenoid isthen free to move the short circuit-ing bar 8 upward. hen the bar 8 reaches the proper point to give the desired speed, the push button G is released and .the

brake magnet immediately stops further upward movement, the magnet belng powerfpl enough to overcome the attractive power of thesolenoid upon. its core. If 1t is desired position, with all ofithe armature resistance removed from circuit, and then immediately moved into position to start the motor, provision is made for preventing the starting until the bar 8 reaches its lowermost position, to include the starting resistance in serice with the motor. To accomplish this result the circuit for shunting thecoil around the magnet pole 29 includes the contact 43 and this shunt circuit can only be completed when the bar 8 is in its lower position in engagement with said contact. Therefore, if

the motor is stopped by the switch F when the bar 8 is out ofengagement with the contact 43 and then the switch F is closed on the contact 40, before the bar S has time to descend the motor will not start until the bar' 8 descends. and engages the contact 43, complete the shunt around the coil on the pole piece 29 of the main switch magnet.

In Fig. 6, the arrangement is the same as in Fig. 1, except that the circuit 32, instead of being connected to the contact 57 is connected directly to the supply terminal 30, and remains permanently energized whether"- the supply circuit switch A be opened or closed, and provision is made for automatically short-circuiting the brake-magnet and operating solenoid at when the supply circuitswit'ch A is opened. 7 As shown, two stationary contacts 90 and 91 are connected'by wires 92. and 93 inparallel with the pushthe stationary contacts 90 and 91 when the switch A is moved into position to stop the motor, and to break the connection between said stationary contacts when the switch A is moved to start the motor. The efiect of bridging the contacts 90 and 91 is the same as closing one of the push buttons H, -that is, it causes the magnet d and solenoid, d, to become shunted and denergized, so that when the switch A is moved to the sto position by the operation of the handswltch F, the contact bar 8 maydescend, but when the switch A moves to the closed or starting position, the shunt around the brake magnet and solenoid is broken and said 'magnetand solenoid immediately become energized. The dead resistance 59 prevents a short c1r-- cuit when the brake magnet and solenoid are and a manually controlled switch and connections for rendering's'aid brake magnet ineflective to prevent such movement.

2. In a controlling. mechanism for electric motors, a main switch for stopping and startingthe motor, a resistance regulating means comprising a contact member and an electromagnetic controlling device normally energized while the" motor is, in operation and constantly tending to move said member to vary the resistance in circuit with the motor, a brake ma et normally preventing suchmovement whlle the motor is in operation, a'manually controlled switch and connections for rendering said brake magnet ineffective to prevent such movement, and

another manually controlled switch and suitable connections for both deenergizing said controllingdevice and rendering the brakemagnet ineffective her. I

3. In a controlling mechanism for electric motors, a main switch for stopping and starting the motor, and re'sistance regulating means comprising a contact member, an electromagnetic moving device normally ener gized while the motor is in operation and tending to move said member to cut',' out resistance, an electromagnetic brake device normally energized while the 'motor'is in operation and normally preventing such to hold the contact memmovement of said member, and a switch and vice without deenergiz'ing said moving de-- -means' compr1s1ng a contact member, a soconnections for d'eenergizing. the brake device. v k

4. In a controlling mechanism for electric motors, a main switch for stopping and starting the motor, and" resistance regulating means comprising a contact member,'a solenoid normally energized while the motor is in operation and tending to move said member to cut out resistance, a brake magnet normally energized while the motor is in operation and normally preventing such movement of the solenoid core, and a swltch and connections for'deenergizing, the brake magnet without deenergizing the solenoid.

5. In a controlling mechanism for electric V v motors, a main switch for starting and stopping the motor, and resistance regulating means comprising a contact member, an electromagnetic moving'device normally energized while the motor' is in operation and tending to move said member to cut out resistance, an electromagnetic brake device, normally energized while the motor is in operation and normally preventing such movement of said member, a switchand connections for deenergizing the brake device without deenergizing said moving device and" another switch and connections for deenergizing both of said devices.

6. In a controlling mechanism for electric motors, a mainswitch for starting and stopping the motor, and resistance regulating means comprising a contact member, an electromagnetic moving device and an electromagnetic brake devicehaving their coils connected'in series across the line,- said devices being normally energized, said moving device tending to normally move said mem her away from said contacts and said brake device normally preventing such movement,

a'manually controlled switch for shunting the. coils of said brake device without shunt- 'ing' the coils of 'said'movingfdevice, a manually controlled switch for shunting the coils -of both of'said" devices and a switch controlled by the main switch for shunting both of said devices when the main switch is I opened to stop the motor.

' 7. In a controllingmechanism for electric motors, a main switch for starting and stop-' ping the motor, and resistance regulating means comprising a contact member, a solenoidnormally energizedwhile the motor is in operation and tending to move said member to 'cut out reslstance, a brake mag-- net normally energized while the motor is in operation and normally preventing such "movement of the solenoid core a switch and connections for deenergizing the brake magnet without deenergizing the solenoid, and anotherswitch and connections for-'deenergizing both the solenoid and the brake magnet.

8. In a controlling mechanism for electric motors, a'main switch for starting and stopping the motor, and, resistanceregulating l'enoid, normally energized while the motor is in operation and tending to move said member-to cut outresistance, a brake mag- "netnormally energized-while the motor is in operation and 'normall preventing such movement'ofthefsolenoi core, a normally open circuit in shunt'to the brake magnet alone, a normally open circuit in shunt to switchesfor cutting in and out said resistance and means for controlling the operation of said relays comprising a series of cona vice arranged to prevent sue tacts connected to the relay circuit, a movable contact member adapted to engage said contacts successively, electromagnetic means for moving said member relatively to said contacts, a brake magnet normally preventing the movement of said member, a switch and connections magnet ineiiective to prevent such movement, and a separate switch and connections for deenergizing said electromagneticmeans and rendering said brake magnet ineffective to prevent the movement of 'said member.

10. In a controlling mechanism for electric motors, an armature resistance, relayswitches for cutting in and out said resist ance and means for controlling the operation of said relays comprising a series of contacts connected to the relay circuit, a movable contact member adapted to engage said contacts successively, asolenoid for moving said member out of engagement with said con tacts, a brake magnet arranged to prevent the operation of the solenoid, said solenoid and magnet being normally energized while the motor is in operation, a switch and con nections for'deenergizing both the solenoid and the brake magnet and another switch and suitable connections for deenergizing the brake magnet without denergizing the solenoid.

11. In a controlling mechanism for electric motors, a resistance in the armature circuit, a series of relay switches for cutting in and out the armature resistance, circuits for shunting the coils of said relays, contacts connected to said shunt-circuits, a contact member adapted to normally bridge said contacts and close said shunt circuits, a solenoid adapted to move said member away from said contacts, a brake magnet arranged to prevent such movement, and means for rendering said brake magnet inefiective to prevent such movement.

12. In a controlling mechanism for electric motors, a resistance in the armature circuit, a series of relay switches for cuttingiin and out the armature resistance, the coils of said relays being connected in series with one another, circuits for shuntingthe coils of said relays, contacts connected to said shunt circu'rts, a contact member adapted to normally bridge said contacts and close said shunt circuits, an electromagnetic moving device adapted to move said member away i m said contacts,-an electroma netic brake demovement, and means 'for rendering said brake device ineffective'to prevent such movement.

13. In a controlling mechanism for electric motors, a resistance in the armature circuit, a series of relay switches for cutting in and out the armature resistance, the coils of said relays being connected in series with one another, circuits for shuntin the coils of said relays.,-contacts connecte to said shunt for rendering said brake,

circuits, a contact member adapted to normally bridge said contacts and close said shunt circuits, a solenoid adapted to move said member away from said contacts, a brake magnet arranged to prevent such novement, and means for rendering said brake magnet ineiiectivc to prevent such movement.

14. In a controlling mechanism for elec tric motors, the combination with a motor,

of armature and field resistances therefor, a relay-circuit, a series of relay switches therein for cutting in and out the armature resistance, a series of contacts connected to said relay circuit, a series of contacts connected to the field resistances, a contactmember adapted to normally bridge said contacts, an electromagnetic device normally tending to move said member away from said contacts while the supply circuit is closed through the armature, a brake magnet normally preventing such movement while the supply circuit is closed, a manually controlled switch and connections for deenergizing the brake magnet without deenergizing said device and another manually controlled switch and connections for deenergizing both the brake magnet and said device.

15. In a controlling mechanism for electric motors, a resistance in the armature cir edit, a series of contacts and a member movable into and out of engagement with said contacts to vary the resistance in the armature circuit, in combination with a supply circuitswitch, an electromagnet having two normally energized coils, for operating said switch, and a circuit for shunting one of the coils of said magnet, said circuit including a manually controlled switch adapted to open automatically when moved to closed position and a contact adapted to be engaged by said contact member when the latter is in its normal position.

-16'. In a controlling mechanism for electric motors, a resistance in the armature circuit, a series of relay switches for cutting in and outthe armature resistance, circuits for shunting the coils of said relays, contacts connected to said shunt circuits, a contact member adapted to normally bridge sai contacts and close said circuits, an electromagnetic device normally energized while the motor-is in operation and tending to move said member to open sa'd shunt circuits, said device having connected therewith a magnetizable rod or bar, a brake magnet, normally energized while the motor IS in operation and co-acting with said revent movement of said member, means or deenergizing said brake magnet without denergizing said device and means for de'e nergizing both said brake magnet and said device.

'17. In a, controlling mechanism for electric motors, a resistance in the armature 011'- bar to ion cuit, a normally open relay circuit comprising a high resistance and a plurality of relay coils in series, relay switches movable by said coils to vary the armature resistance, circuits for shunting the coils of said relays without shunting said high resistance, contacts connected to said shunt circuits, a contact member adapted to normally bridge said contacts and close said shunt circuits, an electromagnetic moving device adapted to move said member away rom said contacts, an electromagnetic brake device arranged to normally prevent such movement, means for rendering said brake device inefi'ective to prevent such movement, and a main switch for opening and closing the armature circuit FELIX R. SULLIVAN, C. W. R. Mooma.

Images