US1452472A - Controller for motors - Google Patents

Description

Apr. 17, .1923. l

f w. PLEHATY CONTROLLER FOR MOTORS Filed Jan.

/NVEA/TR Carl WPZehay f" /W r ATTUHNEYS xmN l/QN WIT/VESSES Patented Apr. 17, 1923.

UNITED STATES PATENT OFFICE.

CARL W. PLEHATY, F WHITE PLAINS, NEW YORK, ASSIGNOR ONE-HALF IIJO FRANCIS R. WHITE, OF WHITE PLAINS, NEW YORK.

CONTROLLER FOR MOTORS.

Application led January 25, 1922. Serial No. 531,791.

T 0 all lwhom 'may concern.'

Be it known that I, CARL YV. PLEHATY, a citizen of the United States, and a. resident of .Vhite lflains7 in the county of lVestchester and State of New York, have invented a new and Improved Controller for Motors, of which the following is a. full,

clear, and exact description.

This invention relates to a controller for l0 motors, and has particular reference to manually operated controllersinfthe form of a starting box. j

The main object of the invention resides in the provision of means whereby the simple moving of the handle of the starting box in the usual direction will not make the proper connections.

Another object resides in the provision of means whereby an especial movement of the handle of the starting bo'X is required before the main line potential can be applied to the motor terminal.

A further object resides in the provision of means whereby if the handle of the starter `box is left on any of the contacts when the power is turned ofi"7 the reapplication of power will not result in any sudden fiow of current through the device which will injure the various parts.

Another object resides in the particular construction and arrangement of parts which are hereinafter described and claimed and shown in the accompanying drawings.

The invention is illustrated in the drawing, in which there is set forth a diagrammatic representation ofthe appara-tus and circuits involved.

The drawing represents only one preferred form which the apparatus and circuits may take in the embodiment of my invention in a commercial device. It is understood that various other arrangements and constructions of the parts and the character of materials used maybe adapted to effect the same operative principle and without departing from the scope of this invention or principle.

As shown in the drawing2 this preferred representation of my invention comprises a double pole switch 1 connecting power lines 2 and 8 with circuit wires 4 and 5 leading to fuses 6 andy 7. Beyond the fuse a starting box is disposed. This starting box coinrises a handle 8 pivoted at 9 and having on its front end face contacts 10 and 11 for a elements 17.

purpose hereinafter to be described. This handle is provided with a knob 12 whereby it can be moved. A piurality of contacting segments 13, 14 and 15 are arcuately disposed with respect to the pivot point of the handle 8 and are adapted to be engaged by the contacting plates 10 and 11 on the end of the handle in a manner hereinafter to be described. Associated with these arcuate contacting surfaces 13, let and 15 are a plurality of spaced contacting fingers such as 16 and 16. In any well known manner a plurality of resistance elements such as 17 is connected between the adjacent fingers 16. The handle is presumed to move in the direction indicated by the arrow in the figure. It will be seen that the first segment with which it contacts is the segment 18 and that associated with this segment are three of the fingers 16. These fingers are normally dead and are not normally used for the purpose of conducting any current. The segment 14 is disposed in an arc of the same circle as the segment 13 and adjacent thereto but separated electrically and mechanically therefrom. Associated with the segment 14 is a plurality of the fingers 16 and their related resistance elements 17. The right end of the segment 14 is connected in the same circumference to a plurality of fingers 16 with their associated resistance To the right of the set of fingers 16 disposed concentrica-lly adjacent the segment 14 there is connected the segment 15.

The fuse 6 is connected by wires 18 and 19 to a contacting finger 20. The normal position of the rheostat arm 8 is shown in dotand-dash line and is opposite the second of the dead contacts 16. The spring-pressed plug 50, hereinafter described more in detail, tends to limit the rheostat larm to this normal position of rest. In order to move it to contact with the finger 20, this plug 50 must bel opposed. It will be noticed that as soon as the rheostat arm leaves the finger 16 and commences to contact with the dead contact, the motor is cut off.

The rheostat handle 8 near its inner end is provided with a projection 53. Adjacent this end of the handley a lever 54 is pivoted at 55. This lever carries on its outer end a bridging contact plate 56 adapted to bridge two contacts 57 and Contacts 57 and 58 are disposed in the wire 27 and are bridged by the plate 56. The other end of the lever 54 is pivoted at 59 to move in an upward direction independently of the rest orp the lever from the normal position shown in the figure. The upward movement of this portion of the leve`rv54 is limited by a stop 61. Relative downward movement of the portion 60 with respect to the lever 54 is prevented. Therefore,-whenever the projection 53 bears downwardly on the portion 60, the -who-le lever is operated; whereas when the projection tends to move the portion 60 upward itmoves upwardly with out effecting the rest vof the lever. The wire 24 extends toa winding 25 of an electromagnet 26, the other end of which winding is connected to a wire 27. Branched from the wire 24 is an additional wire 31 connected to 'a contact finger 32. This finger Vis adapted to be placed in circuit by the 'electro-magnet 26 having an armature plate 37 thereon. The movement of the lever 34 vis'cushioned by a 4finger 38 which is cushioned by a spring 39 ing 40.

One end oit' a field winding 41 of the motor 29 is connected to the wire 30, and the other end is connected .by awire 42 to a field terminal 43 which is connected in turn by awire 44 to the segment 14. The other side of the motor 29 is connected by a wire 45,. to the armaturefterminal 46 which in turn is connectedv by a wire 47 to the segdis'posed within a casvment 15.

In moving from the position of'rest to the left, or in an abnormal direction, the

`by the action of the Spring 49.

In the operation of the device, it is to be assumed that the switch 1 is closed and that the switch arm is in the full-line position shown in the gure. As soon as the switch `1 is'closed, a'plus potential, accordingV to the potential? representation shown inA the drawing, is put on the finger 2O through wires 4, fuse 6, and wires 18 and 19. Therefore, as soon' as the operator takes theswitch erm, inv whatever position he may find it.

and moves it to theextreme left, so as to cause the switclit-o engage the contact 29, the following circuit is closed. This circuit er;- tends from the switch 1, through wire 4, fuse 6, wire 18, wire 19, finger 20, arm 8, wire l fromthe 24, winding 25, wire 27, contacts 58 and 57 and 56, LAruse 7, wire 5, back to the other side of the line through the switch 1. This closed circuit including the winding 25, the circuit of which was closed bythe move ment or" the switch varm 8'to engage the finger 20, will cause the energization of the winding and, consequently, the closing or' switch 34. Assoon as this engagement is made, the following circuit is established: previously established circuit through the fuse 6 and the wire 18, through wire 36, through the pivoted'lever 34, the terminal 33, contact 32, through wire 24, pivot point 9 of the switch arm 8, through the switch arm 8, through contact plates 10 and 11. Tn a well known manner, therefore, through the finger 16- and the resistances 17 disposed between the contact plate 11 and which are in circuit with the -segment 15, theV armature ot' the motor is energized. Also and simultaneously, through the contact plate" 10 being ,in engagement withthe segment 14. the field of the motor is energized inawell known manner. Furthermore, as the switch arm 8 is moved to the rightv the resistance in series with the armature is cut out, while the fields for a certain movementfof the 4'switch arm are maintained constant. After v the switch arm has moved ofi'the resistancef'l7, concentrically arrangedwith respect tor the segment 14, and on to thel segment-.15 then ythe resistance is entirely cut` out ofL circuit with the armature andthe otherfset vof resistances is gradually cut in circuit`wit-h the field. Thisparticular action, of course, is

well known and need not beffurther'- described.

It will be noted, however, that when the pivoted switch member orl pla-te 34 closes the contacts 33 and 32, `it establishes not onlya v power circuit for' a switch armY 8' but also establishesa. holding circuit for the winding 25 as follows from the contactf32, wire 24, winding 25 Vof electro-magnet 26, wire 27,

fuse 7, wire o, back-to the otherside of the line. hand from the knob 12 on the switcharm8 the spring 49 will cause the switch arm toy As soon as theoperator removes his ent holding circuit has been established in the manner above mentioned.r Furthermore, Y

the main circuit for the switcha-rm 8` has been established by the movement -ofthe switch member 34 through a circuit-which is independent of the finger 2O and contacts;

56, 57 f and 58. In other words, from the'beginning of'any operation the main power Y been bridged the circuits above mentioned are established independently of this nger. Assuming that when the operator is through with the machine he opens the switch l without returning the arm .8 to its normal position, and happens to leave it as shown in full line position in the figure, as soon as the switch l is opened the holding circuit through the magnet is opened, causing the deenergization of the magnet 25 and the dropping back of the armature or pivoted switch member 34.' This pivoted switch member by dropping back opens the holding circuit and the main circuit as above traced,

l thereby automatically making the closing of these circuits thereafter dependent upon the closing of the circuits through the finger 20. By this particular arrangement and construction oit the parts, it will be seen that in order to start theI motor after the switch l is closed the operator must move the lever to an abnormal position to the left to momentarily bridge the contact 20, after which he can move the switch arm in the well known manner and speed up the motor. Furthermore, it will be observed that it he happens to leave the switch arm in any position of its travel when he shuts ofi' the power by opening the switch l, that the further closing of the switch l when he wishes to start the motor again will not cause any injury since the application of power through the switch arm cannot taire place until the finger 20 has been engaged and the armature or pivoted member 34 has been turned up by the magnet 26.

Whenever the operator moves the arm 8 oil? the live ngers or contacts 16', as soon as the arm has left these iingers and commenced to contact with the dead fingers 16 the projection 53 on the base of the arm contacts with the end 60 ont the lever 54. By thus lifting the lever the contact 5G is raised from theI contacts 57 and 58 to open the wire 27. This insures that the magnet 26 is deenergized at least for a moment whenever the power arm is moved off the live lingers, even though the operator may go away and leave the switch 1 closed. When the magnet vbecomes deenergized the main switch or lever 34 opens and thereby disconnects the motor from the source of power and also opens the holding circuit for the magnet. However, when the rheostat arm 8 reaches theposition shown in dot-and-dash line in the figure, the projection 53 has passed beyond the end 60 of the lever 54 but allows it to drop back to normal position as shown. Therefore, whenever the operator wants to energize the said magnet he moves the arm 8 as above described to contact with the linger 20, the circuit through the magnet winding having been reestablished. The movement of the arm 8 to the right will cause the engagement of the projection 53 with the end GC' or" the lever, but because of the direction in which the projection is moved the end will pivot around the pin 59 to permit of the passage or the projection 53. The stop 6l will prevent the end portion 60 from reaching a position irom which it would not drop back automatically. This construction prevents unnecessary energization of the winding 25 it' the operator should leave the switch arm l in over night when the arm 8 is on the rest position.

WhatI claimis:

l. A motor controlling` device which comprises a source of current, a rheostat having an arm, a switch, circuit connections between the above mentioned elements including the motor, said switch being normally open, said rheostat arm having normal, abnormal and operative positions, means made effective when the handle is moved to the abnormal position to effect the closing of the normally open switch whereby the power is applied to the rheostat to be applied to the motor in accordance with the further movement of the rheostat handle, and means engaging the handle when moved to its abnormal position, said vmeans when the 'handle is released automatically returning it to a normal position.

2. A motor controlling device which comprises a source of power, a main power switch and a rheostat arm disposed in the circuit between the source of power and the motor, an electro-magnetic device to close said switch when energized, said switch normally being open, circuit closing means connected to the magnet and co-operating with therheostat handle when itis moved to an abnormal position to energize the magnet and close the main switch, and circuit connections established by the closing of the switch to hold the magnet energized until the source of power is disconnected.

8. A motor controlling device which comprises a source of power, a circuit wire leading from said source to the motor, a second wire leading from said source to a main line switch, a wire leading from said main line switch to a rheostat, a wire leading from said rheostat to the other side of said motor, a shunt circuit around said main line'switch, normally open contacts in said shunt circuit, said contacts disposed adjacent the arm of the rheostat and adapted to be closed thereby when the arm is moved to an abnormal position, and a magnet coil to operate the main line switch to close the same, said coil extending` between one side of thel line and a point in the circuit between the main line switch and the rheostat.

4. A motor controlling device which comprises a main line switch normally open, an electro-magnet to close the same, a rheostat for controlling the application of current to said motor, a circuit closing device connected to saidy magnet and operatedjby the rheostat handle when moved reversely to an abnormal `position to energize the mag,-

' net and close themain line switch, and ciri cuit connections established by the closing of normall positiomand means in the circuit aus tomatieally to cause the openingy of said switch when the rheostat arm moves from the operative t0 the normal position.

6. A motor controllingdevioe which comprises a rheost-at having an arm, a main switch, a magnet to close the main switch when energized, circuit means or energiz ing the magnet whenthe rheostat arm /is moved to an abnormal position and to estab-V lish a holding circuit for said magnet, and means actuated by the movement oftherheostat arm from operative to normal position t0 momentarily open the magnet circuit whenever the rheostat arm is moved from `the operative to the normal position.

CARL W. PLEHATY.

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