US654299A - Starting mechanism for alternating-current motors. - Google Patents

Description

Patented July 24, I900.

3 Sheets-Sheet FIG, 70.

J. J. WOOD. STARTING MECHANISM FOR ALTERNATING CURRENT MOTORS.

(Application filed Mar. 80,. 1900,.)

(No Model),

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WITNESSESI No. 654,299. Patented July 24, I900. J. J. WIJUD. STARTING MECHANISM FOR ALTERNATING CURRENT MOTORS.

(Application filed. Mar. 30, 1900.) (No Model.) 3 shaets -sheei 2.

INVENTOR:

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g ji /MW No. 654,299. atented July 24, I900. J. J. WOOD.

STARTING MECHANISM FOR ALTERNATING CURRENT MOTORS.

(Application filed Mar. 30, 1900.)

3 Sheets-Sheet 3,

(No Model.)

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NITED STATES PATENT FFICE.

JAMES J. \VOOD, OF FORT WAYNE, INDIANA.

STARTING MECHANISM FOR ALTERNATlNG-CU-RRENT MOTORS.

SPECIFICATION forming part of Letters Patent No. 654,299, dated July 24, 19.00.

Application filed March 30, 1900. Serial No. 10.746- (No model.)

To aZZ whom it may concern:

Be it known that I, JAMES J. I VOOD, a citizen of the United States, residing at Fort Wayne, in the county of Allen and State of Indiana, have invented certain new and useful Improvements in Starting Mechanism for Alternating-Current Motors, of which the following is a specification.

In the starting of alternating-current motors the current is first turned into a starting-circuit to bring the armature gradually up to speed, whereupon the final circuits are closed and the starting-circuit opened. It is essential to safety that in starting the motor these successive connections should always be made. from the same starting-point. For insuring this operationit is customary to provide a commutator the operation of which closes the motor-circuits in their proper order, a main or line switch for connecting the line or the transformer with the motor, a starting-lever for operating the commutator, and means for making the closing of the lineswitch impossible after it is once opened without returning the lever and commutator fully back to their original or off position. invention provides an improved combination of this character in which the means for operating the line-switch is much simplified.

In the accompanying drawings, illustrating an embodiment of my invention, Figure 1 is a plan view, the commutator being shown in dotted lines. Fig. 2 is a front elevation. Figs. 3, 4, 5, and 6 are plans, partly in section,'showing the successive positions of the parts in the normal operation of the mechanism. Fig. 7 is a similar view showing the position of the parts when the normal operation of the parts has been completed and the forward pressure on the lever removed, the

dotted line showing the position before removal of the pressure, as shown in full lines in Fig. 6. Fig. 8 is a similar view showing the position of the parts in drawing back the lever or after releasing the forward pressure thereon before completion of the normal operation. Fig. 9 is a vertical section on the line 9 9 of Fig. 5. Figs. 10 and 11 area plan and an elevation, the latter partly in section, of the arm on the commutator-shaft. Figs. .12 and 13 are a plan and an elevation of the pawl.

Referring to the drawings, A is (as a whole) a commutator of any well-known type, of which B is the operating-shaft. On the top 0 of the commutator-casing is mounted a main or line switch having a fixed member D and a movable member E, the latter being preferably pivoted at one side of the head, as

shown at F, the switch being held open by a spiral spring, (shown at G.) On the back of the top 0 is mounted an electromagnet H,

having an armature K pivoted at L and with a latch M at its front end. On the movable switch member E is a lug N, adapted to be caught by the latch M when the switch is in the closed position and to be retained on said latch as long as the magnet H is energized and the upper end of the armature K attracted and adapted to be thrown oif the latch M by the action of the spring G when the magnet His demagnetized. On the switch members D and E are a pair of carbon contacts O and P, which complete the circuit through D and E after the metal parts of said switch members separate, thereby saving the metal parts from the effect of arcing, the car- I bon contacts being easily replaceable when burned off. These parts are well known in starting mechanisms for alternating-current motors and do not require any more detailed description.

. On the head of the commutator-shaft B is mounted a cross head or arm Q, Figs. 10 and 11. An operating lever or handle R is pivoted to the arm Q eccentrically of the commutator-shaft and carries a switch-operating member consisting, preferably, of a cam-roller S. The end of the lever nearest its pivot is composed of an inverted triangular-shaped box having a top portion T and depending side flanges U and V extending downward, so as to strike the arm Q when the lever is moved about its eccentric pivot and diverging, as shown in the sectional figures, so as to allow of considerable movement of the lever onits eccentric pivot independently of the arm Q. By this eccentric connection of the lever through the arm Q to the shaft B a limited scribed. This movement throws the cam S to the position shown in dotted lines at S in Fig. 3, thereby increasing its distance from the commutator-shaft. The continued forward movement of the lever is about the commutator-shaft as a center and causes the switch-operating member S to operate the switch by throwing said operating member against the movable switch member E, closing the switch against the resistance of the spring G and holding the switch closed as long as the forward pressure is continued. In order that the closing movement of the switch member E shall be sharp, I provide that the cam S shall strike it at a point near its pivot and abruptly, as by a shoulder 6, instead of .by a gradual pressure. At the same time the commutator-shaft is turned to make the first connections through the starting-circuit of the motor, being then held until the motor reaches synchronous speed, whereupon the lever is turned to its extreme position, (shown in Fig. 6,) thus turning the commutator, so as to make the final connections to the motor and completing the circuit through the magnet H, so as to hold the switch member E in place by means of the latch M and the lug N. If now the lever be moved backward slightly, the cam S is withdrawn to its original distance from the commutatorshaft, as shown in Fig. 7; but the switch D E is held closed by the latch M, since the commutator-shaft has not been moved and the current is still passing through the magnet II. This movement of the lever, however, brings the flange V against the side of the arm Q, and any further backward movement causes the commutator-shaft to turn with the lever. The first result of this movement of the commutator-shaft is the breaking of the main motor-circuit and with it the circuit through the magnet II, the release of the latch M, and the opening of the line switch D E. If now before the lever has been returned fully to its original position it were to be moved forward again, a closing of the line switch would take place and a passage of the current through the operating-circuit without the previous closing of the startingcircuits and bringing of the armature up to synchronous speed unless special means were provided to prevent this result. The means therefore which my invention provides will now be described.

The arm Q is connected rigidly to the commutator-shaft B, (as by means of a boss q, passing through the top 0 of the commuta tor-casing, and a pin q.) Near one end of the arm Q is a pivot (1 adapted to project through the upper portion T of the hub of the lever, the latter being held thereon by a screw g or any analogous means. In order to force the cam S to its position nearest to the commutator-shaft, I provide means such as a spring 0, surrounding the pivot g and bearing at one end against a projection g on the arm Q and at the other end against an arm of the pawl WV, hereinafter described, and through said arm against the flange U on the hub of the lever, thus holding the flange V and the cam S mounted thereon against its side of the arm Q. The tension of this spring is less than the friction of the commutator-shaft.

In order to prevent the protruding movement of the cam S in any position of the commutator except its initial or off position, I preferably provide a pawl IV, (see Figs. 12 and 13,) which is pivoted to the under side of the portion T of the lever, as shown best in Fig. 9, and which has a depending extension 10, against which one end of the spring 0' constantly bears. In the normal operation of the device the pawl being immovable by the spring serves to transmit the force of the spring to the lever, and thus to bring the flange V against the side of the arm Q, as explained above. To coact with said pawl I provide a stop g on the arm Q, which is preferably an extension of the stop (1 It will be seen that the tendency of this pawl, in conjunction with the spring *1" at any intermediate position of the lever, is to throw or to hold the lever and the arm in the position shown in Figs. '7 and 8-that is, with the flange V bearing against the arm and with the pawl \V engaging the stop q, so that the forward movement of the lever from this point carries the cam S in a small circle about the commutator-shaft as a center, as shown by dotted are at in Fig. 8. The relative positions of the commutator-shaft and the movable switch member E are such that when the cam S is rotated in this smaller circle or are about the commutator-shaft it does not strike the switch member, as shown by the dotted line 00 in Fig. 8; but, as explained above, when the cam S has been moved to the greater distance from the commutatorshaft, such as S in Fig. 1, a rotation of the cam about the shaft will then bring the cam into contact with the switch member and throw it to close the switch, as shown in dotted lines in Fig. 7.

Although it is essential that commencing from an intermediate position it should be impossible for the movement of the lever to produce a closing of the line-switch, which is effected by the arrangement of the pawl and spring described, yet the mechanism must be such as to permit a closing of the lineswitch when the lever is started from its original position. This result is effected, preferably, as follows: On the top 0 of the commutator-casing is a pin or stop X, in such posi tion as to strike the depending arm w of the pawl and throw said pawl outward against the depending flange Y of the box-shaped lever end. This action takes place just as the lever is-brought back to its original position and serves to stop the lever in that position, as well as to throw the pawl out of engagement with the arm Q. The lever is now free to move forward on its eccentric pivot, the first movement carrying the pawl past the end of the stop if, thereby rendering the pawl ineffective, a further movement protruding the cam S from its shorter to its longer distance from the. commutator-shaft, and the continued movement operating the switch and commutator-shaft, as first described.

The function of the various parts of my mechanism having been described in detail, I will now describe the operation of the entire mechanism.

In the off position of Figs. 1 and 3 the commutator has cutoff all the connections in the motor, the line-switch is also open, and there is no current through the magnet H. The lever has been pushed back hard until the arm to on the pawl W is pressed forward by the 'pin X, and the pawl is clear of its stop (1 on the arm Q. The first slight movement of the lever in the direction of the arrow in Fig. 1 carries the pawl past the stop q, and the spring 0 now forces the pawl inward without effect. The lever turns first on its eccentric pivot (1 the strength of the spring 0" being less than the friction of the commutatorshaft. The further movement of the lever brings the flange U against the side of the arm Q, as shown in Fig. 4, throwing the cam S from the full-line position shown in Figs. 1 and 3 to the position shown in dotted lines in Fig. 3 or in full lines in Fig. 4. In the position of Fig. 1 the distance of this cam from the commutator-shaft is such that if rotated about the commutator-shaft as a center the arc described by the cam would not touch the movable switch member E; but in the extended or protruded position of Fig. 4 a rotation about the commutator-shaft causes the cam S to describe an are which would coincide with the inner edge of the switch member E if the switch were fully closed. The continued forward movement of the lever from the position of Fig. 4 can be only about the commutator-shaft as a center. It therefore carries the cam S against the abrupt shoulder e of the switch member E, as shown in Fig. 5, and throws the switch sharply to the closed position, the lug N being caught by the latch M, which, however, has no power to hold it since there is no current in the magnet H. Continuing the forward pressure on the lever the cam S holds the switch member E in the closed position while the motorarmature is coming up to speed, whereupon the operator swings the lever over to the position ofFig. 7, causing the current to pass through the magnet H, so that the switch member E is now automatically held in place by the latch M. The forward pressure on the lever may now be removed, when the action of the spring 7 will throw the lever from the dotted-line position R to the full-line position B, Fig. 7, the pawl W being throwninward by the force of the same spring and engaging the stop q. The cam S is at the same time moved to its nearest distance from the commutator-shaftand is'held locked in such distance by the pawl W. Further movement of the lever B in either direction turns the commutator-shaft correspondingly, but has no other effect. If therefore the lever be brought back to a middle position, Fig. 8, the first effect of such movement is to break the last connection made by the commutator, thereby cutting off the current from the magnet H and allowing the spring G to open the line-switch D E, the latch M having no longer power to hold the switch member E in place, and hence stopping the motor. Further movements of the lever therefore are absolutely without effect, the current from the line being entirely out off.

If before reaching the final position shown in dotted lines in Fig. 7 we suppose that the operator releases the forward pressure on the lever B, the switch D E is immediately opened, the latch M being ineffective, and the cam S being immediately thrown back to the inoperative position, Fig. 8. To make the line connection, it is therefore, as before, necessary to return the lever fully back to its original position. By this means the possibility of accident is entirely obviated. In starting the motor it is essential to press the lever forward continually, to the end, and after stopping it is absolutely essential in order to start again that the lever be returned to its original position and the motor brought up to speed by making the necessary connections in their regular order.

Although I have described my mechanism with great particularity of detail, I am not to be understood as limiting myself to the specific mechanism shown and described, since many modifications thereof will readily suggest themselves to those skilled in the art'to which this invention pertains. For example, the switch operating member S though shown as a cam may be any other equivalent mechanical element or combination and instead of being protruded from the commutator-shaft might be moved into operative position in other ways, which will readily suggest themselves to those skilled in the art, or the connection of the lever to the commutator and to the switch-operating member may be varied in detail by the use of mechanical equivalents therefor, without departing from the principles of the invention.

What I claim,therefore, and desire to secure by Letters Patent, are the following-defined novel features, substantially as set forth and described:

1. In combination, a main switch, a coinmutator, a common lever for operating said switch and said commutator, means whereby the initial movement of the lever renders it operative to close the main switch, and the continued movement thereof closes said main switch, and means whereby a backward movement of the lever renders it inoperative to close the main switch until after it has been returned to its zero or off position.

2. In a motor-startin g mechanism, the com- IIO bination of a switch, a commutator, an operating-sha'ft therefor, a lever adapted to operate said shaft, a switch-operating member, means tending normally to hold said member in an inoperative position, and means for moving said member into an operative position by the forward movement of said lever.

3. In a motor-starting mechanism, the combination of a switch, a commutator, an operating-shaft therefor, a lever adapted to operate said shaft and to have a movement inde pendent of said shaft, a switch-operating member adapted to be moved into operative position by said independent. movement, means for connecting said lever to said shaft so as to prevent said independent movement, and means for withdrawing said connection in the original position of the parts so as to permit said independent movement.

4-. In a motor-starting mechanism, the combination of a switch, a commutator, an operating-shaft therefor, a lever adapted to operate said shaft, a switch-operating member, means tending normally to hold said member in an inoperative position, and means whereby the forward movement of said lever first moves said member into an operative position and then causes said member to operate said switch.

5. In a motor-starting mechanism, the combination of a switch, a commutator, an operating-shaft therefor, a-lever adapted to operate said shaft, a switch-operating member, means whereby an initial forward movement of said lever moves said member into operative position, means whereby the continued forward movement of said lever causes said member to operate said switch, and means for automaticallyreturning said member and locking it in its inoperative position upon removal of the forward pressure on said lever.

6. In a motor-starting mechanism, the combination of a switch, a commutator, an operating-shaft therefor, a lever adapted to operate said shaft, a switch-operating member, means whereby an initial forward movement of said lever varies the distance of said member from the comm ut-ator-shaft, means whereby the continued forward movement of said lever moves said member to operate said switch, and means for automatically returning said member and locking it at its original distance from said shaft upon the removal of the forward pressure on said lever.

7. In a motor-starting mechanism, the combination of a switch, a commutator, an operating-shaft therefor, a switch-operating member, a lever connected eccentrically to said shaft and adapted to operate said shaft and said switch-operating member.

8. In a motor-starting mechanism, the combination of a switch, a commutator, an operating-shaft therefor, a lever mounted eccentrically on said shaft, a switch-operating member carried by said lever, means for connecting said lever to said shaft so that the initial movement of said lever is about its eccentric pivot and the continued forward movement of said lever turns said shaft.

9. In amotor-starting mechanism, the combination of a switch, a commutator, an operating-shaft therefor, a lever connected eccentrically to said shaft, a switch-operating member carried by said lever, means for permitting an initial movement of said lever about its eccentric pivot so as to vary the distance of said switch-operating member from the commutator-shaft, means for transmitting the continued movement of said lever to said shaft, and means for automatically returning said switch-operating member and looking it at its original distance from said shaft upon removal of the forward pressure on said lever.

10. In a motor-starting mochanism,the combination of a switch, a commutator, an operating-shaft therefor, a lever connected eccentrically to said shaft, a switch-operating member carried by said lever, flanges on said lever on either side of said shaft, whereby an initial independent movement of said lever on its eccentric pivot is permitted and the continued movement of said lever operates said shaft.

11 In a motor-starting mechanism, the 001m bination .of a switch, a commutator, an operating-shaft therefor, a lever connected eccentrically to said shaft, a switcheperating member carried by said lever, flanges on said 1ever on either side of said shaft whereby an initial movement of said lever on its eccentric pivot is permitted, and the continued movement of said lever operates said shaft, a pawl adapted to connect said lever to said shaft so as to prevent said initial movement, and means in the original position of the parts for holding said pawl out of action.

12.. In a motor-starting mechanism, the combination of a switch, a commutator, an operating-shaft therefor, a lever pivoted eccentrically to said shaft, a cam on said lever adapted to operate said switch, means for permitting an initial movement of said lever about its eccentric pivot whereby the distance of said cam from said shaft is varied, and means for permitting a continued movement of said lever about said shaft whereby said cam operates said switch.

13. In a motor-starting mechanism, the combination of a switch, acommutator, a commutator-operating shaft, a lever pivoted eccentrically to said shaft,a cam on said lever adapted to operate said switch,means forpermitting an initial movement of said lever about its eccentric pivot whereby the distance of said cam from said shaft is varied, means forpermitting acontinued movement of said lever about said shaft whereby said cam operates said switch, and means for automatically returning said cam and locking it at its original distance from said shaft upon removal of the forward pressure on said lever.

14. In a motor-starting mechanism, the combination of a switch, a commutator, an operating-shaft therefor, an arm Q, on said shaft,

a lever B pivoted on said arm near the outer end thereof, flanges U and V on said lever at either side of said arm separated a greater distanee than the width of said arm and limiting the movement of said lever on said pivot, a pawl V on said lever, a stop (1 on said arm, and a spring 1' pressing said lever into a position with its flange V against said arm and pressing said pawl inward toward its stop to hold said lever in said position.

15. In a motor-starting mechanism, the combination of a switch, a commutator, an operating-shaft therefor, an arm Q on said shaft, a lever R pivoted on said arm near the outer end thereof, flanges U and V on said lever at either side of said arm separateda greater distance than the width of said arm and limiting the movement of said lever on said pivot,

a pawl W on said lever, an arm w on said pawl, a stop g on said shaft-arm Q, a spring 1 pressing said lever into a position with its flange V against said arm and pressing said pawl inward toward its stop to hold said lever in said position, a fixed stop X adapted to strike said pawl-arm w when said lever is retraeted to its oif position, and a flange V limiting the outward movement of said pawl and thereby limiting the backward movement of said lever.

In witness whereof I have-hereunto signed my name in the presence of two subscribing witnesses.

JAMES J. lVOOD.

Witnesses:

F. S. HUNTING, W.-H. CRIGHTON.

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