US836036A - Automatic motor-starter. - Google Patents

Description

No. 836,036. PATENTED Nov. 1s, 1906. W. F. HENDRY.

AUTOMATIC MOTOR STARTER.

APPLICATION FILED 00T.l6. 1905.

3 SHEETS-SHEET l.

N0. 836,036. PATENT'ED NOV. 13, 1906. W. P. HENDRY.

AUTOMATIC MOTOR STARTER.

APPLICATION FILED O0T.16. 1905.

3 SHEETS-SHEET 2.

No. 836,036. PATENTED NOV. 13, 1906.

f W. P. HENDRY.

AUTOMATIC MOTOR STARTER.

APPLICATION FILED 0OT.16. 1905.

3 SHEETS-SHEET 3.

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, fnl/6735107@ UNITED 'STATES PATENT OFFICE.

wiLLIAM F. HENDRY, or NEW YORK, N. Y., A'ssIeNoR `rO'wEsrInrN yELECTRIC COMPANY, or CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

AUTOMATIC MOTOR-STARTER.

Patented Nov. 1e. 1906.

Application tiled October 16, 19,05. Serial No. 282,995.

To all whom it may concern.-

Be it known that I, WILLIAM F. HENDRY, a citizen of the United States, residing at New- York, in the countyr of New York and State of New York, have invented a certain new and useful Improvement in Automatic Motor-Starters, of which the following is a full, clear, concise, and exact description.

` My invention relates to a device for gradu- I ally and safely regulating the'flow of current through a motoriwhen it is beingstarted in motion, and has for its object the automatic short-circuiting of the starting resistance of an electric motor.

Various means have been devised for first admitting a weak current to the motor and gradually increasing the current until the full strength for which the motor is adapted It hasbeen customary to include resistances in .the armature-circuit, through which the current iirst l'ows when: the switch is closed, and to gradually cut out the resistances vater the Inotor has startedQ One well-known means comprises a series of:

is reached.

electromagnets arranged top-be successively of the motor increases and so connected as to control the resistance in the motor-circuit." The various methods hitherto devised fort gradually cutting out the starting resistance,

however, are open to more or less seriousob-l` jections.

In my invention the solenoids which oper-v ate the switch for short-circuiting the steps or blocks of resistance are adapted to operate successively upon the closing of the motor main swi ch, said solenoids being controlled by a relay whose actuating-coil is in series with the armature-circuit and which is therefore itself controlled by the fluctuations of the current in the motor-armature. This allows of rapid acceleration under a light load and very gradual acceleration under a heavy load, resistance being cut out at ex-v actly the proper moments in -a step-by-step method until the full current stren th for which the motor is adapted is reache I will describe my invention more particularly byreference rto the accompanying drawings, in which- Figure 1 is a diagram showing the course of the main and shunt currents through the motor and starting device, the actuating,

coils of the resistance-solenoids being con,-

nected across the line in series. Fi 2 -is a modified form of the arrangement s own in Fig. 1, by which the controlling-relay is short circuited' when the entire armature resistance is cut out. Fig. 3 is a diagram of the circuits of my invention, showing the actuating-coils of the resistance-solenoids connected in parallel across the line.

The sameletters of reference are used to designate the same parts wherever they are shown.

As illustrated in the drawings, when the switch yis closed to connect the motor with thelinains the current from the terminals wil be closed through armature resistance R', relay S, and armature-motor M. The resistance R is arranged in a plurality of steps or blocks. The strength of current flowing through solenoids S S2 S3 is controlled by relay S. The plungers of said solenoids operate switches s s2 s3, respectively, for successively. cutting out the .steps or blocks of resistance R. While for purpose of description I have shown the armature resistance arranged vin three blocks and ada ted to be cut out by threeswitches, it is o vious thatany desired number of blocks and switches may be used.

The relay S, which is'in series with the arL mature-circuit, is adjustable, so that it may be arranged to ol erate'at any desired current. In Figs. 1 an 2 a system is illustrated in which both series and shunt fields of the motor are employed. In, said igures the Windings of the solenoids are shown connected across the line in series with each other and in series with a parallel circuit, one branch of which has a resistance R2 andk the other branch has two switches, one controlled bythe solenoid S3 and the other by the relay S. When the resistance R2 is inserted,it prevents the solenoids S S2 S3 from receiving enough power to operatep'the switches s s2 sa, thou hlt permits sufficient current to pass to ho d the switches firmly closed after they have been once lifted toa closed position.

Referring to Figs. 1 and 2, the operation of my step-by-step automatic motor-starter is as follows: When the main switch is closed, the current flows through the armature and the starting resistance R', which allows a current to pass of any predetermined amountsay about ifty per cent. above the normal runningfcurrent oI' the motor.

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is adjusted to operate at this current and opens the contact a, which opens the short circuit around the resistance R2. The resistance R2 is thus inserted in the branch circuit in series with the solenoids S S2 S2 and is of such value as not to permit a flow of current of suflicient strength to operate any of said solenoids. As the motor-armature speeds up the flow of current in the circuit including relay S is reduced thereby and the relay S releases its armature, thus closin contact a and short-circuiting resistance 2. This increases current through solenoids S S2 S2, which are arranged to operate at different current strength. Enou h current passes through solenoid S to liIt its plunger and close switch s', thereby cutting out one step or block of the starting resistance R: As a result the current through the armature-cirouit increases uickly to fifty per cent. above normal, the ne ay S again operates as before, and the resistance R2 is a ain inserted in the branch circuit of the so enoids before the current through the solenoid-circuit has increased sufficiently to lift the plunger ef another solenoid. The resistance R21 reduces the current throu h said solenoids Sulliciently to prevent rther operation of 'the solenoids, but permits the flow of enough curnent to hold the switch s firmly in place. When the current through the armature again dies down, owing to the motor speeding up, the relay Sa ain releases its armature, thereby closin t e short circuit around resistance R2, and t e solenoid S2 operates to close the switch s2, thereby cutting out a second block of the resistance R. Thereupon the flow of current through thearmaturecircuit immediately increases to operate the relay S to insertthe resistance R2 inthe solenoid-circuit. The flow of current throu h the solenoids is then sufficient to hold t e switches s s2 closed, but is insurlicient to close the switch s2. The above cycle of operations continues until the resistance R is by this step-by-step method entirely cut out as the motor gets up to s eed.

When the solenoid S3 closes the switch s2 and cuts out the last block of the armature resistance, the lunger of said solenoid opens the switch b, t ereby inserting resistance R2 in the solenoid-circuit in order to protect the rhesistance-solenoids SS2 S3 from excessive est' In ig. 2 I have shown a short circuit for relay S, said short circuit being closed when the solenoid S3 closes its switch to cut out the last block of the resistance.

In Fig. 3 I have shown my invention with the actuating-coils of the solenoids S S2 S3 connected across the line in parallel with each other and in series with a parallel circuit, one branch of which has the resistance R2 and the other branch a contact a', controlled by the armature of the relay S.

armature and ythe resistance R2 is short-circuited. The solenoid S thereupon operates the switch s to out out a portion'of the armature resistance. As soon as the solenoid s pulls up its plunger the top of said solenoidlrame is energized and the solenoid S2, whose coil is electrically connected to the frame of solenoid S', is included in the branch circuit in parallel with S and receives current; but since the cutting out of a block of the resistance R increases the low of current through relay S said relay is operated to again include the resistance R2 in the branch circuit, owing to which the current flowing through the coil of solenoid S2 is insufcient to actuate it. As soon as the solenoid S2 raises its plunger the solenoid S2 is likewise thrown in parallel with solenoids S and S2.

When in the arrangement shown in Fig. 3 enough current passes through the solenoid S3 to lift its plunger and cnt out the entire resistance R', said plunger also operates a switch c, thereby opening the circuit to solenoid S', which in turn opens the circuit to solenoid S2. S3 is therefore the only solenoid whose coil receives current after the motor is up to speed, at which time a resistance R2 is inserted in series with the solenoid S2 to protect the same.

It will be observed that when the solenoids are connected in series, as illustrated in Figs. 1 and 2, .all of said solenoids receive current after the armature resistance has been entirely out out, Whereas when said solenoids are connected in parallel, as illustrated inY Fig. 3, only one coil receives current after the armature resistance is short-circuited. It will also be observed that both in Figs. 2 and 3 the relay S is short-circuited with the lest ste of resistance.

Ii when any switch closes and cuts out a block of the starting resistance the current in the armature-circuit does not increase to the desired amount above the normal running-current of the motor by reason of a very light load or any other cause, then the armature or' relay S will remain unattracted and allow one or more of the other solenoids to operate until enough resistance is cut out to increase the current to 'the predetermined amount. Ii, on the other hand, the motorcurrent should not fall as the speed of the IOO IIO

` trolledlby said solenoids for successively out` i revolution of the armature increases, by reason of some defect in the motor or on account of an excessive load, the relay-armature Will remain attracted, and therefore the cutting.

out of any resistance Will be impossible.

Thus my invention provides simple means for regulating safely and automatically the flow of current through the motor-armature'.-

Iclaiml. lin a 'motor-starting device, the combination with the motor, of a resistance in' cluded in the circuit of the motor-armature, a branch circuit including a plurality of solenoids adapted to operate at different current strength', switches operated by said solenoids for successively cutting out steps of said resistance, and a single relay in series With the armature-circuit and, controlled by the flucf tuations in the motor-current vfor directly controlling theI flow of current through said solenoids.

2. in a motor-starting device, the combination with the motor, of a resistance and a relay included in the circuit ofthe motor-armature, vswitching means controlled by said relay for successwely cutting out steps of said resistance, and a short circuitfor said relay closed When saidreslstance 1s entirely cut out.

3f The combination With a motor having a startin resistance in its armature-circuit, "of a plura ityof solenoids connected across the line in'parallel With each other, switches` controlled by said solenoids for successively'cutting out steps of said resistance, and a single relay in series with the armature-circuit and controlled by the liuctuations'in the motor.- current for controlling the flow of current through said solenoids.

4. The combination With a motorl having a startin lresistance in its armature-circuit, ora plura ity of solenoidsconnected across the line in parallell with'each other, switches conting out steps of said resistance, a relay in series with the armature-circuit controlling the iioW of current through said solenoids, and means operated by one of said solenoids for short-circuiting said armature resistance, said relay and the other of said solenoids.

5. The combination With a motor having a startin resistance in its armature-circuit, of a plura ity of solenoids adapted to operate at different current strength and having a resistance in their circuit, a relay in series With the armature-circuit and controlled by the iluctuations'of the motor-current to cut in or out said solenoid resistance, switches operated by said solenoids for successively cutting out steps of 'said armature resistance, and means whereby the operation of the slowestactin lsolenoid inserts resistance in the solenoi -circuit.

6. The combination with a motor having a startin resistance in its armature-circuit, of a plura ityof solenoids adapted to operate at dHerent current strength and having a resistance in their circuit, means in series with ythe armature-circuit and controlled by the iiuctuations 'of the motor-current to cut in or out said solenoidjre'sistance, and switches operatedby saidisolenoids for successively cutting out steps of said armature resistance.

7. The combination with a motor, of a starting resistance in its armature-circuit, a plurality of solenoids adapted `to operate at different current strength, switches, for successivelyy cutting out steps of said resistance, controlled by said solenoids, a resistance in `the circui-t` of said solenoids, and a relay in the armature-circuit for controlling said resistance in the solenoid-circuit.

In Witness whereof hereunto subscribe my name this 10th day of August, A. D. 1905.

. WILLIAM F. HENDRY.

Witnesses :r

ALBRIGHT, A. C. Dones.

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