Патент USA US2068494код для вставки
Jan. 19, 1937. Q w KUHN ET AL 2,068,494 ELECTRICAL CONTROL DEVICE Filed Nov. 2, 1931 mgg'l 5 ?"1 (: ' w. 3 ?31 680 Z A51 66 ______ 5&7 wt 15 4 _ a ,,,,,,,, ,1 9 a1 /_6 '66 ' � 55 �5.25 �58 "@294 _ 2,068,494 Patented Jan. 19, 1937 UNITED STATES _ PATENT OFFICE ' 2,068,494 ELECTRICAL CONTROL DEVICE Clarence Wilbur Kuhn and Clyde F. Robbins, Mil waukee, Wis., assignors to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Dela ware Application November 2, 1931, Serial No. 572,586? ? 5 Claims. (01. 175-7335) This invention relates to electrical control de - vices and is particularly applicable to starting devices for electric motors. The copending application of William C. Stevens and George J. Meuer, Serial No. 309,537, ?led October 1, 1928, discloses a push button operated starting device for electric motors in ciuding a pair of contact elements, one 'of which is normally open and is operable to control line 10 connections for the motor, and the other of which is normally closed and is operable to con trol a starting resistance in the motor circuit. The contact elements are provided with an op erating mechanism including start and stop push 16 buttons and upon depression of the former push button both of said contact elements are moved out of normal position with a snap action to es tablish line connections for the motor and to in clude the starting resistance in the motor cir cuit. Immediately upon release of the start trated and that certain features of the invention are capable of use in connection with control devices of various types other than that shown in the drawing. In the drawing, Figure l is- a front elevational view of a motor starter embodying the invention. ' Fig. 2 is a side elevational view of the starter shown in Fig. 1, together with a sectional View of an enclosing casing therefor. 10 Fig. 3 is a sectional view taken substantially on line 3-3 of Fig. 1. ~ Fig. 4 is an enlarged sectional view of an elec tromagnetic restraining device shown in Figs. 1, 2 and 3. 15 Figs. 5 and 6 are end views of the core member, of the electromagnetic restraining device shown in Fig. 4, illustrating such core member in dif ferent positons with respect to its cooperating armature member, and 20 Fig. '7 is a diagrammatic view illustrating the push button the resistance controlling contact element returns to normal position to shunt the circuit connections for the starter shown ?in Fig. 1. starting resistance and the other contact ele The starting device illustrated is provided with ment is heldin closed position to maintain line a switch mechanism of the character disclosed 25 connections for the motor by a latching mech 25 in the aforementioned copending application of anism which is releasable by the stop push but William C?. Stevens and George J. Meuer. Such ton. The present invention relates to motor starters ?' mechanism includes a pair of U-shaped contact of the aforesaid character, and has among its levers l and 2 arranged in opposed relation and objects to provide automatic means which acts having their adjacent ends pivotally mounted 30 so upon momentary depression of the start push upon bearing projections 3 and 4 formed?upon a-U-shaped bracket 5 ?xed to an insulating base button to delay return of the resistance control ling element to normal position for an interval 6. ? Each of the contact levers i and 2 has an which is su?icient to prevent excessive current insulated bridging contact mounted upon the free end thereof, the bridging contact 1 asso 35 in the motor circuit upon exclusion of the start 35 ciated with lever I being adapted to cooperate ing resistance. with a pair of stationary contact devices 8--8 Another object is to ?provide a starting device for alternating current motors having improved and the bridging contact 9 associated with lever electromagnetic means associated therewith for 2 being adapted to cooperate with a pair of sta tionary contact devices Ill-40. As shown in 40 40 automatically timing interruption of starting Fig. '1, the two pairs of contact devices 8-8 and connections and establishment of rurming con- l0-?lll are mounted upon opposite ends of in nections in accordance with predetermined cur sulating base 5. Each of the contact devices rent conditions in the motor circuit. 8-8 is provided with a contact ?nger 8EL to be Another object is to provide an improved elec engaged by bridging contact ?I when lever i oc 45 46 tromagnetic restraining device which is adapted cupies the position shown in Fig. 2, and each of for use in connection with alternating current motor starters and control devices of other types the contact devices Ill-l0 is provided we a contact ?nger Hi?1 to be engaged by bridging con and which is readily adjustable to vary the re tact 9 when lever 2 occupies the position shown straining effect thereof. I 50 in Fig. 3. Various other objects and advantages of the 50 The operating mechanism for contact levers l invention will hereinafter appear. and 2 includes a tension spring I2 which iscon The accompanying drawing illustrates an em bodiment of the invention which will now be nected at opposite ends to the free ends of con tact levers I and 2 by insulating links I3. As is described, it being understood that various mod apparent from Fig. 3, movement of the axis of 55 i?cations may be made in the embodiment illus 20 2 2,068,494 spring l2 in opposite directions across a plane joining bearing projections 3 and 4 provides for snap movement of contact levers I and 2 in oppo site directions between the positions illustrated in Figs. 2 and 3. Spring l2 passes through an opening in a reciprocable operating member I4 having a push button I5 ?xed to the outer end thereof. Operating member I4 is supported ad jacent its inner end within an opening in brack et 5 and is supported adjacent its outer end with in an opening in a frame I6 ?xed to said bracket. A spring I1 biases operating member I4 outward ly towards the position shown in Fig. 2. Said spring is held under compression between a wash 15 er I8 mounted upon said member and a plate I9 ?xed to the rear face of base 6 by screws I3? which also serve to secure bracket 5 to said base. Contact lever 2 has a latch 20 associated there- _ with for locking the same against movement out 20 of the position shown in Fig. 3. Latch 20 is piv otally mounted upon a pin 2I carried within a recess in the outer face of frame I6 and the same is provided with a shoulder 22 for engaging a projection 23 on contact lever 2. Latch 20 25 is also provided with an inclined cam surface 24 Magnet 30 is mounted upon an insulating plate 3i which also carries the aforedescribed switch mechanism and resistance element R. Said mag net has an energizing winding 32 which is mounted upon a cylindrical core member 33 and said core member is secured to plate 3| by a screw 34 which passes through said plate from the rear thereof into a centrally located tapped opening in the rear end of said core member. The outer end of core member 33 projects beyond 10 winding 32 and is slotted at 35 to provide a pair of pole projections 36 and 31 for attracting a projecting armature member 38 ?xed to the free end of contact lever I. The pole projection 35 is surrounded by a plurality of D-shaped shad 15 ing coils 39 which are secured to said projection by turned over portions 40 on the end of the latter. These shading coils are adapted to act in a well known manner to prevent chattering of the armature member 38 upon core member 20 33 by producing magnetic fluxes of different phase in the pole projections 36 and 31. As hereinbefore set forth, magnet 30 serves to prevent return of contact element I to normal position until the current in the motor circuit 25 to be engaged by a reciprocable tripping member drops to a value such as to prevent an excessive 25 having its inner end supported within an open ' current rush in the motor circuit upon exclusion ing 25 in base 6 and having its outer end pro of the starting resistance element R. In prac vided with a push button 21 which is supported tice it is desirable to provide for adjustment of 30 within an opening in frame I6. Tripping member the current value at which magnet 30 is adapted 25 is formed to provide a face 25? for engaging to release contact element I, and for this pur 30 the cam surface 24 on latch 20 and said tripping pose said magnet and its cooperating armature member is connected to said latch by a spring 28. 38 are so designed that by loosening screw 34 Spring 28 serves to bias tripping member 25 out the magnet may be rotated with respect to the 35 wardly towards the position shown in Fig. 3 and armature member. The width of the armature also serves to bias latch 20 upwardly for engage ment with the projection 23 on contact lever 2. As is apparent, depression of push button 21 causes the face 25a of tripping member 25 to 40 engage the cam surface 24 on latch 2|] to move the latter downwardly for release of contact lever 2. The above described switch mechanism may be connected as shown in Fig. 7 to effect starting and stopping of an electric motor M. As is ap 45 parent from the foregoing, upon depression of push button I5 contact levers I and 2 are moved with a snap action from the positions shown in Fig. 2 to the positions shown in Fig. 3 to there by move bridging contact 9 into engagement with 50 its cooperating stationary contacts IlJ"--~II)n and bridging contact 1 out of engagement with its cooperating stationary contacts 8L4?. With the circuit connections shown in Fig. 7 motor M is then connected across a source of current in55 dicated by lines L1?L2 in series with a starting resistance element R and a magnet 30 which will be hereinafter more fully described. Upon release of push button I5 contact lever 2 tends to return to the position shown in Fig. 2 to dis 60 connect the motor from the supply circuit but the same is held in the position shown in Fig. 3 by its associated latch 20 which is adapted to be tripped as hereinbefore set forth upon depression of push button 21. Also upon release of push 65 button I5 contact lever I tends to return imme diately to the position shown in Fig. 2, in which position bridging contact 1 engages its cooperat ing stationary ?contacts lie-8? to exclude the starting resistance element R and magnet 30 70 from the motor circuit. However, magnet 30 serves to hold contact lever I in the position shown in Fig. 3 until the current in the ?motor circuit drops to a value such as to prevent an excessive current rush upon exclusion of resist 75 ance\element R. 35 member 38 is less than the diameter of the core member 33 and by rotating the magnet with re spect to the armature member the area of the face on pole projection 31 which is overlapped by the armature member 38 can be varied as shown 40 in Figs. 5 and 6. As is apparent, the reluctance of the magnetic circuit between pole projection 31 and armature member 38 can thus be ad justed to vary the current value at which magnet 30 is adapted to release its cooperating arma 45 ture member 38. Also as is apparent, rotative adjustment of the magnet about its axis varies the distance of the pole faces of pole projec tions 31 and 38 from the pivot of contact element I to also effect variation of the current value at which said armature is released. In manufacturing the aforedescribed switch mechanism the angular position of the armature member 38 with respect to the core member 33 is likely to vary, as indicated by full and dotted lines in Fig. 4. This tends to vary the holding 55 effect of the magnet 33 upon the armature mem ber. However, in practice it has been found that by maintaining an air gap between pole projection 31 and the armature member 38 vari ations in the angular position of armature mem ber 38 with respect to core member 33 will pro duce only a negligible variation in the holding effect of the magnet upon the armature mem ber. As shown in Fig. 4 in order to maintain an air gap between pole projection 31 and the armaturemember 38, pole projection 35 projects beyond the former pole projection and serves as an abutment for said armature member. The aforedescribed switch mechanism is pref erably mounted within a box shaped enclosing casing II which is provided with a cover 42 hav ing openings therein for receiving the push but tons I5 and 21. Also if desired the latch 28 may be provided with overload tripping means of the y. 2,068,494 character disclosed in the copending applica tion of Clarence W. Kuhn, Serial No. 460,461, ?led June 11,? 1930. The tripping means dis closed in this application is of the electrothermal type and is adapted to respond upon overloads in the motor circuit to trip latch 20 for stopping of the motor and is also adapted to be reset by the switch operating mechanism. What we claim as new and desire to secure by 10 Letters Patent is: 1. The combination with a control device in cluding a movable control part, of a holding wind ing therefor to be supplied with alternating cur rent, a core member for said winding having a 15 shading coil associated therewith to provide mag netic fields of different phase for attracting said control part to hold the same in a given position, and supporting means for said core member ,per 3 said armature member, a shading coil associated with said core member and surrounding one of the divisions thereof, and supporting means for said members permitting relative adjustment of said armature and core members to vary the overlap of said armature member with respect to certain of. the pole faces on said core member for variation of the holding effect of said winding. 4. The combination with a control device in cluding a movable control part having an arma 1O ture member associated therewith, of a holding winding therefor to be supplied with alternating current, a core for said winding divided to pro vide a pair of pole projections having pole faces to cooperate with an overlapping pole face on 15 said armature member, one of said pole projec tions being adapted to abut said armature mem ber and to maintain an air gap between said mitting rotary adjustment thereof about its axis 20 for variation of the holding effect of said mag netic ?elds upon said control part. armature member and the other of said pole projections, a shading coil \surrounding said 20 former pole projection, and supporting means for 2. The combination with a control device, in cluding a movable control part biased towards a given position, said part having an armature 25 member associated therewith, of an alternating current electromagnet for attracting said arma ture member to hold said control part in another position, said magnet having means associated therewith to provide magnetic ?elds of different said core permitting adjustment thereof with re spect to said armature member to vary the over 30 phase for attracting said armature member, and a support for said magnet permitting adjustment thereof with respect to said armature member to provide for variation of the reluctance of one of said magnetic fields without substantial vari 35 ation of the reluctance in the other of said mag netic ?elds. _ 3. The combination with a control device in cluding a movable control member having an armature member associated therewith, of a 40 holding winding therefor to be supplied with alternating current, a core member for said winding divided to provide a plurality of pole faces to coact with an overlapping pole face on lap of said armature member withv respect to the pole face' of said last mentioned pole pro 25 jection. 5. The combination with a control device in cluding a movable control element having means associated therewith for biasing the same to wards a given normal position, of a winding to 30 be supplied with alternating current, and means associated with said winding to provide ?uxes differing in phase for attracting said control element to hold the same in another position, said means being adjustable with respect to said 35 control element to vary the attractive e?ect of one of said ?uxes upon said control element with out substantial variation in the attractive effect of the other of said ?uxes upon said control element. 40. CLARENCE WILBUR KUHN. CLYDE F. ROBBINS.