US943047A - Apparatus for starting and stopping electric motors. - Google Patents

Description

C. SPANNAGEL.

APPARATUS FOB. STARTING AND STOPPING ELECTRIC MOTORS.

APPLICATION FILED JUNE 1,1909.

Patented Dec. 14. 1909.

3 SHEETS-SHEET 1.

ql s. i h lig-A z-Il- A.` as

C. SPANNAGEL.

APPARATUS FOR STARTING AND STOPPING ELECTRIC MOTORS.

APPLIUATION FILED JUNE 1,1909A 943,047. Patented Dae. 14.1909.

3 SHEETS IHEET 2.

C. SPANNAGEL.

APPARATUS FOB. STARTING AND STPPING ELECTRIC MOTORS.

APPLICATION FILED JUNE 1, 1909.

Patented Dec. 14, 1909.

3 8HBET8-BHEBT 3.

l YV WZ CARL SPVANNAGEL, OF

MANNHEIM., GERMANY, ASSIGNOR TO ZUCKERFABRIK FRANK- ENTHAL, 0F FRANKENTHAL, GERMANY.

APPARATUS FOR STARTIING AND STOPPING ELECTRIC MOTQRS.

Specication of Letters Patent.

Patented Dec. 14, 1909.

Application mea :une 1. isos. semina. 499,268.

To all whom 'it may concern:

Be it known that I, CARL SPANNAGEL, engineer, a subject of the King of Bavaria, residing at Mannheim, Germany, have irlvented new and useful Improvementsin Apparatus for Starting and Stopping Electric Ljlotors, of which the following is a specification.

In apparatus for starting electric motors it is known to'introduce aspring between4 the driving device and the switchi apparatus, and to have operatin upon this latter a double pawl controlled y` the armature current which .only allows a slow step by step movement of the switching apparatus. In these devices, however, account is only taken of the starting and not of the stopping of the motor, for which aslow step by step movement of the switching apparatus is equally `of great importance, es ecially if it is desired to return current to t e line or to brake the motor in a purely electrical way.

According to this invention, the disadvantage mentioned is avoided by placin the switching apparatus under the action o one spring lspecially for starting and one for l stopping, and connectinit rigidly with the notched wheel for the (lsouble pawl.

In the drawings an a paratus for starting and stopping a D. C. siunt motor is shown :is an example of the invention.

Figure 1 is a cross section throughthe switching apparatus, Fig. 2 shows a switching apparatus in section on theline A-B of Fig. 1 and in connection with the auxiliary device serving to move the pawls. Fig. 3 is a diagram of connections.

The special switchn apparatus consists in the tirst place of an insulating base plate a in which is fastened the pivot b and on the front of which are arranged four Sets of contacts in circles. The outermost set of contacts includes the arc c1 and the contacts The second set of contacts reckoned from without inward, consists of the arcs d' and d2, the third set .of contacts includes the arc el and the contacts e2-e, the innermost contact finally is formed by the closed ring On the pivot b is revolubly mounted the contact wheel upon the back of which are mounted the insulated brushes g" and g2, the brush g rubs upon the sets of contacts c and d, while the brush g2 rubs on the sets 4 of contacts e and The Contact wheel p has three rims /L lc which are provided wit i notches and are ada ted to co-act with the pawls m n o. `On t ie front of the switch wheel g is provided a pin p. On the pivot 5 there is also revolubly mounted a cap g on the front of which is the handle g1. The edge of the cap g at the back is formed as a flange which is provided with three notches g for engagement with the pawl r. Upon tlie hub gf of the cap g are fastened two spiral springs s1 s2, one of which is right-handed and the other left-handed. rlhe outer ends of the spiral springs li to the right and left of the pin p' of the switch wheel g.

The pawls m n 0 are loosely revoluble around pivots fastened in the base plate a. The pawl n, turns upon the same pivot as the pawl o and is fitted with a nose piece nl which lies beneath, the pawl o. If, therefore, the latter is turned to the left, it moves the pawl n with it. On the other hand so long as the pa'wl o is in the position shown, the pawl n can engage iii the slots of the rim i without moving the pawl o. lVliile the teeth of the remaining pawls are rigid, that n2 of the pawl n is elastically mounted. It moves upon a pin n and is guided in a slot on the inner side of the pawl n. Upon the pin n are wound two spriii s u* nl on the two sides of the tooth n?, an these ress in opposite directions so as to normal y hold the tooth a2 in the position shown. Solenoids it and u serve on the one hand for the movement of the pawlsy m and o, and on the other hand for the movement of the pawl n, their cores t' and ul being illustrated in their normal position in Fig. 3. The cores are connected below to the pawls m ando, respectively by rods t2 and u2, while springs *u* and 'v2 act on their upper ends, 'v1 tending to move the core l downward, and 'u2 to move the core u'2 upward.

w is a relay formed as a solenoid, the core w which serves to move up and down the contact piece w2 (Fig. 3). This is conductvel connected with the contact w, and in its owermost position lies against the contact fw* while in its highest position it touches the contact ws.

In Fig. 2 is illustrated a form of construction of the contact piece w! differin somewhat from that in Fig. 3, and this wi rial.

be described in urtherdetail below.` With the contact Iw3 there co-acts a switch which is acted upon by-a spring w1 and carries at its lower end a piece :v2 of insulating mate- This, in the position of rest illustrated, lies between the tooth k of the rim l: and the nose of the pawl 0.

y* is the armature and y2 the magnetlwinding of the motor to be controlled.

The interconnections of the different parts and their relation to the switching devices can be understood, without further explanation, from F' 3.

The methol of operation of the construction described may be first explained withreference to Figs. l and 3, while the form of relay w according to Fig. 2 will, as above remarked, be ldealt with in detail later.' In order to start the motor, the main switch z is closed and the cap is turned to the left by means of the han e g1 when the pawl r has been lifted out 'of the notch g. According as the motor is to run at full speed ora `less speed, the revolution is continued until either the notch g* or the notch g isbeneath the pawl r. For the sake of simplicity, it. may be supposed that the motor is to be run at full speed. Then, as already mentioned, the cap g will be turned to the left about 330 and the pawl 'r will engage in the notch q. On the closing of the main switch a the magnet winding y2 of the motor first receives current .along the following path: positive pole z, y2, l, e, three parts of the shunt resistance, e, g2,-2, cl, 3, a, to the negative pole. As the cap g is turned to the left, the spring s, the inner end ofwhich is connected to the boss g5, is stretched. The outer end of the spring engages with the'pin p and so turnsthe switch wheel q to the left with it. This latter can at first rotate upon itsI shaft without hindrance. The tooth -k of the` rim k leaves the switch a: free, and this hitter presses against the contact w". B v this means the solenoid t is energized through the following circuit: positive pole, a, 4, w, w3, 102, w, t, 5, negative pole. The core t1 is then drawn up andthe pawl m prevented from engaging in the notches of the rim h. vUpon the fu'rther revolution of the switch wheel g the three parts of the shunt resistance between e13 and el are cut out, and thc brush q1 moves over the contacts c' to c without the armature y* receiving current thereby. This only happens when the brush g1 comes into contact'with c and the current then takes the followino circuit: positive `pole, z, 1, 6, w, 7, all t e seven parts of the startling resistance c, g1, 3, z, negative pcie of the mains. The arnratsre gf therefore turns and takes so much current that the relay fw attracts its core w1. As the result of this, the solenoid t is cut out and the solenoid u energized. The circuit of the latter is as follows: positive pole z, 4, w, rto,

w, ze, 8, u, a, negative pole. The pawl m `falls back upon the rim la, and so comes into engagement lwith the notch k1, which like the -fo owing notches does not revent a further turning of the switch w eel to the left.. Through excitation of the solenoid u, the pawl o is moved downward and engages iu a notch la so that the switch Wheel can turn no farther. Since, however, the current in the armature y* now diminishes because the resistance in circuit is notl lessened, the relay w after a short time allows its core wl to fall again and so cuts out the solenoid u. The switch wheel g then turns farther to the left until the strength of the current through to armature y* is again increased suiciently to effect the closing of the circuit of the solenoid u` by means of the relay lw. In consequence ofthisfthe pawl o engages in the next notch k2. 4This operation is repeat-ed as the starting resistance is cut out step by step until the pawl o vengageswith the notch k". Aslsoon as it emerges from this notch the tooth n2 of the pawl n comes into operation. This latter engages in the notch z" and is moved .by this as far as the slot in the'un der end of the pawl n allows. In its end position, however, ,the toothu2 holds the to z" can be provided prior to this notch so as to operate for exalnplewith the notch Isl. In general, however, this is not necessary because at the beginning of the starting of the motor the current passing does not increase so speedily as later. When the whole starting resistance hasbeen cut out, that is when the brush g1 cornes into contact with the arc c, the shunt resistance between c* and e12 is inserted in the circuit of the magnct winding y2 step by step. Finally, the tooth k of the switch wheel g comes against the projection a1 of the base plate a and therefore its revolution ceases During thel normal driving of the motor` the contactl the motor circuit first excites the relay 'w so A strongly that it excites the solenoi'd 1.'. The same operation then proceeds as at starting. that is. the pawl o is alternately raised and lowered so that the switch wheel can only 4ture circuit.

turn step b step. The switching of the nietes whica new returns current to the line, is first of all only changed by the grad ual cutting out of the shunt resistance and gradual insertion ofv the starting resistance. The magnitude. of the starting resistance is su chosen that the E. M. F. at the brushes of the motor is'somewhat greater than the potential of the supply, so that the relay w receives the necessary current. Thus the operation proceeds until the brush. g. leaves the contact c. So soon as the brush gl comes a ainst the contact c, the current" generate by the armature yl, takes'the following path: y1, 6, w,- 77 0*, slx parts of the sturting. resistance, c, 9,- c, g, d2, 10, yf. The circuit of the armature. y is therefore now closed over a resistance and is no longer connected to the supply terminals. U on the further revolution of the switch w eel to the left, the' resistance in the armature circuit is diminished. Finally the brush g1 leaves the contact c2 and so. opens the arma- In the last part of the movement` of the switch Wheel to the right, the pawl o comes into engagement with the notches k5-k.

The manner of operation of the pawl m has intentionally been referred to onl at the commencement of the exposition oV the switching process. As is Obvious .without further explanation, from what has i been said above and from the drawings, this pawl always lies upon the rim k when no current is flowing through the winding of the solenoid t. This is the case, however, so long as the strength of the current through the motor armature does '.ot go below a certain limit. Now the armature current can be below the limit in question on the one hand, on the starting of the motor, if no current at all is flowing through the motor armature,

-that is if thebrush g does not at least rest upon the contact 0, and on the other hand upon the stopping when the brush gl has at least come into contact with the contact c. If the brush gl rests on the Contact c in starting and in stopping, the vpawl n begins to coperate with the notches i-]z,2 or hB-h which are beveled u on one side.

The notches hL--L2 consequent y preventtheV revolution of the switch wheel to the right, and the notches /i-i,, revolution to the left as soon as the pawl m engages in them. The purpose of these notches and of the pawl m is thus to prevent a reversal of the direction of revolution foi` the time being of the switch wheel so long as current of the determined strength flows through the'armature.

A form of construction of the rela w in Fig. 2 differing somewhat from that 1n Fig. 3, has a contact piece to2 which, by means of the rod wt, is suspended as a pendulum on the core w'. The center of gravity of the contact piece wz, the position of which can oe re elated hy small auxiliary weights w', lies tween the point of engagement with the rod w and the knife edge w on which the contact piece 'wz lies in the position of rest. In this osition the left hand end is also resting on tie contact -w. If the core 'w1 is drawn 1n, the left hand end of the contact piece rw2 leaves the contact w and 'touches against the knife edge wg. Upon further increase of the current in the wind in of the relay w, the Contact piece fu;2 is li ted .aboutV the knife ed e wg and rests against the` contactpfw. T e screws of the .contacts w* and w5 are -so adjusted that in this latter position the Contact lw* is not closed. If the current strength diminishes again, the contact piece rw2 turns about the knife edgewg. Its right handend .therefore moves away from the contact w, but also does-its lcft hand end from the contact -fw. The purpose of this arran ement is'to prevent immediate re-closing o the contact' 'w upon variations of the armature current, which may `easily occur.

Although in the preceding only one form of constructon of the invention has been described, w ich relates to thestarting and stopping of a direct current motor and particularly to one in which on stopping, current is to be returned to the line, it is clear without further explanation that by corresponding alteration of the Contact pieces e-f, the construction can be applied in an entirely similar way for other motors, that is to say d. c. motors connected in other ways as well as for alternating current and three phase motors. Finally it is also to be rc marked that the new apparatus is suitable for distant control. The' handle g1 is then removed and a cord orthe like is wound around the cap g. This cord is moved in one direction or the other by a lever, a second cord pulley, or the like. The notches q-q are then mounted upon the device which serves to move the spring.

I claim:

1.v In an lapparatus for starting and stopping electric motors a control member, a switching member, two sprin s acting in opposite direction interposed tween said two members, a solenoid, a double pawl operated by said solenoid and acting u )on two notched rims rigidly connected wlth said switching member. Vsubstantially as and for the purpose set forth.

2. In an apparatus for starting and stopping electric motors a control member, a

switching member, two springs acting in opposite direction interposed between said two members, a solenoid, a double pawl operated by said solenoid and acting upon two notched rims rigidly connected with said switchin member, the double pawl being formed gy two parts having a little free 13d motion and one of said yielding tooth, substantial purpose set forth.

3. In an apparatus for starting and stopping electric motors a control member, a switching member, two springs acting in opposite direction interposed between said two members, a solenoid, adouble pawl operated by said solenoid and acting upon two notched rims rigidly connected with said switching member, a second solenoid, a third pawl operated by said second solenoid and acting upon a thlrd notched rim rigidl connecte with said switching member, su stantially as andjor the purpose set forth.'v

4. In an apparatus for starting and stopping electric motors a control member, a switching member', two springsl acting in opposite direction interposed between said two members, a solenoid,a` double pawl operated byV said solenoid and acting upon two notched rims rigidly connected with said switching member, a 'second solenoid, a third pawl operated by said second solenoid and acting upon a third notched rim rigidly connected with said switching member, a relay controllin saidy two solenoids and being traversed y the armature current, substantially as and for the purpose set forth.

5. In an apparatus for starting and stopping electric motors a control member, a switching member, two springs acting in opposite direction interposed between'said two members, a solenoid, a double pawl operated by said solenoid and, acting upon two notched rims rigidly connected with said switching member, a second solenoid, a third pawl operated by said second solenoid and acting upon a third notched rim rigidly connected with said switchin member, a relay controlling said twio'solenolds and being travlparts carr ing a y as and or the ersed by the armature current, the contactpiece of which in one of its end sitions closes the circuit of the one solenoi and in the other en d position that of the other Solenoid while during normal running oftthe motor it rests against neither of its contacts, substantially as and for the purpose set forth.

6.l In an apparatus for starting and stopping electric motors a' control member, a switching member, two springs acting in opposite direction interposed between said two members, a solenoid, a double pawl operated by said solenoid and acting upon two ,notched rims rigidly connected with said switching member, a second solenoid, 'a third pawl operated by said Second solenoid and actin upon a third notched rim rigidly connecte with said switchin member, a relay controlling said twro solenoids and being traversed by the armature current, the contact piece o Said relay on leaving the working contact being at first also moved away from its other contact, substantially as and for the purpose set forth.

7. In an apparatus for starting and stopping electric motors a control member, a switching member, two springs acting in opposi direction interposed between said two mem rs, a solenoid, a`double pawl operated by said solenoid and acting upon two notched'rims rigidly connected with said switching member, a second sdlenoid, a third pawl operated by said second solenoid and actin upon a third notched rim rigidly cons ncte with said switching member, a relay controlli g, said two solenoids and being traversed y the armature current, said rela receiving its current throu h a switch which is openedV by the switc ing device when the motor is at a standstill, and automatically closes when the switching device leaves the position of rest, substantially as Aand for the purpose set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CARL SPANNAGEL.

Witnesses:

S. H. SHARK, WILIL Cr S'rooxnnn.

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