US1141548A - Controlling device for motors. - Google Patents

Description

F. HYMANS. CONTROLLING DEViCE FOR MOTORS.

APPLICATION FILED APR- I0, 19]].

1,141,548. Patented June 1, 1915.

2 SHEETS-SHEET l.

O 0 3 2 :/6 l7 2 L9 96- 4- mveu'ron F. HYMANS.

CONTROLLING DEVICE FOR MOTORS.

APPLICATION FILED APR.10,19II.

Patent-ed June 1, 1915.

2 SHEETS-SHEET 2- WITNESSES UNI ED STATES PATENT OFFICE FREDERICK HYMANS, or srmLEn TowNsnIP, arnnennm ooUnTY, rmsynvnmi, ASSIGNOB To OTIS ELEVATOR com-m, or JERSEY CITY, mew .nmsmr, A conrw RATION or, new mnsny.

cons-manna mzvrce FOR MOTORS.

Specification of Letters Patent.

Patented J une 1, 1915.

lpplieat ion flled A il 10, 1911. Serial No. 619,956.

To all whom itimay concern:

Be it known that I, FREDERICK HYMANS, a subject of the Queen ofHoll and, and residen'tof Shaler township, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Im rovements in Controlling Devices for Nhotors, of which the'following is a specification.

The invention relates to motor controlling apparatus, andhas for its primary objects; the rovision of improved means for effecting the acceleration of the motor to full speed automaticallyand in relation to the load on the motor; the provision of improved means of the character specified that are applicable to both direct and alternating currents; the provision ofautomatic means for cutting out the starting resistance, so arranged that the device will not operate to cut out the resistance in case of an overload on the motor; and the provision of an arrangement of controlling windings vfor the cutting out switches, so arran that such windings will be automatical y short circuited when the starting resistance is cut out. Certain embodiments of my invention are shown in the accompanying drawings, wherein Figure 1 is a diagrammatic view showing the application of the invention to "a direct current motor, Fig. 2 is a view similar to that of Fig. 1, but with a modified arrangement of switch control, the apparatus being controlled from a masters switch. 'Fig. 3 is a partial diagrammatic view showing a modified arrangement for securing the release of the cut out switches by means of a connection to the brake operating mechanism, and Fig. 4 is a diagrammatic View showing the application of the invention to an alternating current motor of the induction type.

In Fig. l'the invention is illustrated as applied to a direct current 'shuntmotor in connection with a manually operated main switch. In this figure 1, and 2 are the positive and negative mains, 3 is the armature, 4 is the shunt field, 5 and 6 are portions of the starting resistance designed to be successively cut out as the motor speeds up, 7 is a manually operated main switch provided with the contact member or brush 8, and 9 is a contact segment with which the contact member is adapted to engage when the switch is moved from open \to closed position. Integral with the switch arm is a pinion segment 10 designed to interrnesh with a vertical rack 11, suitably guided, and having a rest 12 beneath the plate 13 carried by the end of the rack. 14 and 15 are the windings of what may be termed the accelcrating magnets, of which there are two-as illustrated, but which may be' used sl my desired number, depending upon me hamber of stepsin which the starting resistance is to be cut out. windings14 and 15 are the solenoid rods l'and 15', which rods are pivoted at their lower ends to the switch arms 16 and 17, such switch 'arms carrying at their outer ends the contact members 21 and 20, and at their inner ends the set screws 18 and 19 Working through thewith which the plate 13 is adapted to en gage. The weight of the rack 11 and the plate 13 bearing against the set screws 18 and 19 normally holds the switch arms 16 and 17 with their contacts 21 and 20 in the position shown, but when the plate 13 is raised, the switch arms tend to swing by gravity downward so that the contact members 20 and 21 engage respectively with the contact members 23 and 22. 14 and 15 are connected in parallel with the starting resistance 5 and 6 by means of the wire 27, and are energized by reason of the difierence in otential betweenthe points 24 and 25 o the resistance. IVhen the switch arm 17 is in closed position with the contact 20 upon the contact 23, the portion 5 of the starting resistance is short circuited by reason of the connections 28, 29 and 30, and when the contact member 21 is against the contact member 22, the entire starting resistance 5-6 is short circuited by the connections 28, 31 and 32.

The windings The operation of the apparatus is as folonce to occur between its terminals 24 and 25. The windings 14 and 15 will therefore become energized, and are of sufficient strength to hold the switch arms 16 and 17 in the position shown, even after the holding plate 13 .is raised, the winding 14 being of greater strength than the winding 15. A further movementof the switch arm 7 in the direction of the arrow will cause the engagement of the pinion segment 10 with the rack 11, the rack being moved upward and thus carrying the holding plate 13 away from the set screws 18 and 19. At this time the switches 16 and 17 are held in the-po sition shown by reason of the action of the current in the windings 14 and 15 upon the solenoid bars 14 and 15, the windings being of sufiicient strength to maintain the.

switch arms in raised position as long as the maximum current flows through the armature, that is, when the greatest potential dif ference between the terminals of the starting resistance 24, 25 occurs, so that the switch arms remain in their uppermost po sitions in case the motor should stall under.

an over-load. If however, the motor speeds up, the counter-electro motive force generated by the rotation of the motor will reduce the current that the armature receives. Consequently less current will pass over the starting resistance, with a corresponding decrease of the potential difference between the points 24 and 25. Thewindings 14 and 15 thus receive less current, and their magnetic pull decreases. As the motor continues to gain speed, the magnetic pull of'the windings decreases more and more, until finally a point is reached where the winding 15, being made initially with the weakest magnetic pull, drops its switch arm 17, permit ting the contact 20 to engage the contact 23, and thereby short circuiting the portion 5 of the starting resistance, the current passing fromthe point 26 through the connections, 30, 29 and 28 to the armature. The cutting out of the portion 5 of the starting resistance will cause a new increase of current with a new accelerating impulse on the motor, with the stronger winding 1-1 still receiving suflicient current to maintain the switch arm 16 in open position. With the further acceleration of the motor, however,

: ed correspondingly, will no longer be able to hold the switch arm 16 in upper position, and it will therefore drop, making the contact between the parts 21 and 22, and thereby short circuiting the entire starting resistance 56, the current passing through the the starting resistance, the only requirement: I

being that these windings'shall be subject-- ed to a potential which diminishes as the motor increases in speed. It will also be seen that with the arrangement as shown.

in Fig. 1, the windings 14 and 15 receiveno current when all of the starting resistance is cut out, as these windings are short circuited simultaneously with the short circuiting of the starting resistance.

be very small, all of which tend'to permit the use of small inexpensive magnets. It will be understood that F ig. 1 is merely illustrative of the invention, and that the construction-of the main switch, the means for releasing the switch arms, and the man ner of connecting the windings are capable. of much variation.

In Fig. 2 are shown substantially the same arrangements as in Fig. 1, with the exception that the switch controlling mechanism is different, a master switch being employed instead of thedirect acting switch in Fig. 1. In this arrangeinentthe solenoid bar 33 is employed instead of the rack bar 11, such bar being controlled by means of the wind ing 34. 35 is the master switch which is adapted to have'its contacts 36 and 37 successively engage its segments 38 and 39. 40 is still another switch having a contact 41 adapted to engage a contact 12 when the switch is closed, the switch being operated by means of a winding 43 operating the They therefore receive current only a short pe-- riod, and their air gaps can be arranged to.

solenoid bar 44. Starting with the parts in the position shown and the motor at rest the operation is as follows. The arm 35 is moved in the direction of the arrow, making the contact between the parts 36 and 38. Current then flows through the winding 3 via the connections 45, 4G and 47 energizing such winding and causing the closure of the switch 40. The closure of this switch completes the main circuit, and causes the starting of the motor in the manner heretofore described in connection with Fig. 1. A further movement of the switch cau es the engagement of the contacts 37 and 39, thus permitting current to flow through the winding 34 via the connections 48 and 49, thus energizing this winding and causing the lifting of the solenoid 33, thus releasing the set screws 18 and 19, after which the operation of the device is precisely the same as heretofore described in connection with Fig. 1.

In Fig. 3 I have illustrated still another manner in which the release of the additional holding means for the switch arms for cutting out the starting resistance may be controlled. This is accomplished in this case by utilizing the brake which is ordinarily used in connection with a motor of this class for securing the release. As shown in this figure, 50 is the drum, 51, 52, are the brake arms normally held in braking position by means of the spring 53, 54 and 55 are solenoid plungers carried the brake arms 51 and 52 respectively and working in the winding 56, and 57 is a connecting arm between the brake arm 51, and a holding member 13, which holding member corresponds to the plate 13 in Figs. 1. and 2, and engages the set screw 18 of the switch arm 17, corresponding in all respects to the same parts in Figs. 1 and It will be seen that when current is supplied to the solenoid winding 56 to release the brake arms 51 and 52 from the drum 50, such movement causes the lifting of the member 13 and thus leaves the switch arm 17 to operate in the manner heretofore described in connection with the operation of the device shown in Figs. 1 and 2. The member 13 is shown as engaging only the set screw of a single switch arm, but it will be understood that this i'nember 13 may engage simultaneously any number of set screws carried by a plurality of switch arms, each designed to out out a portion of the starting resistance.

The invention is also readily applicable to alternating current of which Fig. +1- is an illustration as applied to a three phase induction motor with the starting resistance in the rotor or secondary circuit, in connection with a main circuit closed by a manually operated main switch. In this diagram 7 is the main switch arm having thereon the brushes or contact members 58, and 60 adapted to contact with the segments 61, G2 and 63, and supplied with three phase current from the mains (it, (35 and 66, the segments (31, 62 and (53 being connected with the three terminals 67, 38 and. (39 of the stator. 70, 71 and 72 are the three slip rings of the rotor connected to a starting resistance 73 to 75, 76 to 78, and 79 to 81, which resistance may be arrangci'l in any desired form of connection. star, delta or otherwise. 14 and 15 are windings for controlling the operation of the switch arms 16' and 17', such arms 10 and 17 being provided on their ends with metal contact members 82 and 83 adapted to connect the contact terminals 84, 85 and 86, and 87, 88 and 89, which terminals are connected to the slip rings and to the starting resistance portions 74 to 75, 77 to 78, and 80 to 81 ofthe resistance are cut out, and that when the switch arm 17 ,is in closed position with the member 83 contacting with the contacts 87, 88 and 89, all of the resistance is cut out of the secondary circuit. The winding 14 is weaker than the winding 15, so that the resistance is cut out in two stages in the manner heretofore described in connection with Fig, 1, but it will be understood that this arrangement is merely illustrative, and that the arrangement may be modified to provide for the cutting out of the resistance in any desired number of steps or stages.

Having thus described my invention and illustrated its use, what I claim is new and desire to secure by Letters Patent is the fi'1liowing 1. In combination, a motor, 'a source of electric supply, a main switch arm for controlling the motor circuit, a motor starting resistance, a secondary switch for controlling the starting resistance and constructed to close when not acted upon externally and cut out the. said starting resistance, an electro magnetic winding in shunt with respect to said resistance and tending to hold the secondary switch open when current is flowing theretl'n'ough, releasable means out of ccntact "with the main switch arm adapted to hold the secondary switch open, and means whereby movement of the main switch arm first closes the motor circuit and thereafter engages the releasable means.

2. In combination, an alternating current induction motor. a source of electric supply,

main switch arm for controlling the motor circuit, a variable resistance in the secondary circuit of the motor, a secondary switch mecl'ianism arranged to normally close and cut out such resistance, a releasable means out of contact with the main switch arm for holding the switch mechanism against closure, and means whereby movement of the main switch arm first closes the motor circuit and thereafter engages the releasable means.

3. In combination, an alternating current induction motor, a source of electric supply, a main switch arm for controlling the motor circuit, a variable resistance in the secondary circuit of the motor, a plurality of secondary switches each arranged to control a portion of the said resistance and-each adapted to normally close and cut out a portion of the said resistance, releasable means for holding the switches against closure, an electro magnetic winding for each switch in shunt with the said resistance and each arranged to hold its switch openwhen sutficient current is flowing thorothrough, the said windings being of different strength so that one portion of the re tame after another is cut out as the speed of the motor increases, and means whereby mtwmnent of the main switch arm first doses he motor circuit and thereafter engages he role noble means.

4. In combination, an aiteznat induction motor, a source of (:ieviru r v a main switch arm for controliingg the motor circuit, a variable resistance in the sec" ondary circuit of the motor, a, secondary switch arranged to normally close and cut out a portion of such resistance, a releasable means out of contact With the main switch arm for holding the switch against closure, and means whereby movement ot the main switch arm first closes the motor circuit; and, thereafter engages the releasable means.

5. In combination, an alternating current induction motor, a source of electrical supcurrent ply, a main switch arm "for controllim the motor circuit, a variable resistance secondary circuit of the motor, a sir--- switch arranged to normally wloso tain out a portion of such ififliftitlhit, magnetic winding in shunt uflih it the said resistance and tenzlinn to her} 3 switch open when current is: i'tafxiiiig! there through, releasable means out of contact with theinain switch arm zulu 'ited. to h hl the secondary switch open and mom 4 whereby movement of the limiil switch air first closes the motor circuit and. ti areal engages the releasable means.

in testimony whereof I have hereon: s gned my name in the presence of the t subscribed Witnesses.

ii alvvtio F. H Yh'IANS.

\Yitnesses Domino Bnuimonu, J ULIAZN H. Knr'oio.

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