US1511567A - Method and device for the automatic starting of continuous or alternating current motors by means of contact devices - Google Patents

Description

Oct. 14 1924.

. 1,511,557 P. H. F. LAMBERT METHOD AND DEVICE FOR THE AUTOM ATIC STARTING OF CONTINUOUS OR ALTERNATING CURRENT MOTORS BY MEANS OF CONTACT DEVICES Filed Jan. 14, 1922 3 Sheets-Sham. 1

.Ruiflfjam 5812 1,511,567 F. METHOD AND DEVICE FOR THE AUTOMATIC STARTING OF CONTINUOUS OR Oct. 14 1924.

P. H. LAMBERT ALTERNATING CURRENT MOTORS BY MEANS OF CONTACT DEVICES Filed Jan. 14, 1922 3 Sheets-Shoot 2 P. H: F LAMBERT I w'raon AND DEVICE FOR THE AUTOMATIC STARTING OF CONTINUOUS ORV ALTERNATING CURRENT MOTORS BY MEANS 0: QONTAGT DEVICES Fiied Jan. 3,4,, 19% 3 Sheotq+8hut 5 EaZEFZ mi vi Patented Oct. 14, 1924.

UNITED STATES PATENT OFFICE.

PAUL HENRI FREDERIC LAMBERT, OF PARIS, FRANCE.

METHOD AND DEVICE FOR THE AUTOMATIC STARTING .OF CONTINUOUS OR ALTER- vNATIN'G CURRENT MOTORS BY MEANS OF CONTACT DEVICES.

Application filed January 14, 1922.

T 0 aZ-Z whom it may concern-.-

Be it known that I, PAUL HENRI FREDERIC LAMBERT, a citizen of the Republic of France, and residing at Paris, Seine Department, No. 12 Rue Portalis, in the Republic of F rance, have invented certain new and useful Methods and Devices for the Automatic Starting of Continuous or Alternating Current Motors by Means of Contact Devices, of which the following is aspecification.

Numerous devices are already known which have been constructed for the purpose of automatic starting of continuous current motors, irrespectively of their method of excitation, as well as for the starting of alternate current motors. The major part of the said devices comprises a plurality of electro-magnetic contact switches (commonly termed contactors) which serve to throw the various sections of the starting resistance successively inor out of circuit in a given order, and are adjusted in such manner as to operate upon a given value of the main current or of the counter-electromotive force of=the motor.

As a rule, each switch is provided with auxiliary contacts inserted into an operative or control circuit. In this manner when the contact switch is closed, the auxiliary switches ,are connected together and the current is caused to flow in the operating or control circuit of the contact switch which is to enter subsequently into action. In these conditions, the closing of each contact switch will provide for the possible closing of the following contact switch, and of-this switch exclusively.

But the short circuiting of a section of the starting resistance will produce in the main circuit a sudden increase of current which gives rise to accelerating torque and will only end when the counter-electromotive force of the motor has sufficiently increased. It is therefore necessary that the following contact switch shall not close except when the current has again fallen to a given value. To this effect'each contact switch is provided with a second auxiliary switch controlled by airelay termed acceleration 'relay'having the main current flowin in its winding and which is so adjuste that the said switch shall be unable to close before the current fallsbelow .a given value for which the relay has been adjusted. This known device Serial No. 529,278.

has been improved by an interlocking arrangement whereby the maximum safety of operation is afforded and the following conditions are complied with.

1.Tl1e opening of the contact switch necessarily brings about the opening of the auxiliary switch co-operating with the acceleration relay.

2.The closing of the contact switch permits the closing of the said auxiliary switch without actually effecting the same, whereby this closing may be retarded by a device acting under the influence of the main current.

A known device is constructed wherein the interlocking thus set forth is carried out by mechanical means. But this device has a drawback from the fact that it obliges each acceleration relay to be mounted immediately below the corresponding contact switch which is intimately connected therewith, and it also requires an adjustment which is often long and difficult of the mechanical parts in operation, for the acceleration relay is locked and released by the lever of the contact switch.

Various devices are also known wherein the interlocking is carried out by electrical means. One of these devices comprises contact switches and acceleration relays which are independent in the sense that each'acceleration relay is interlocked without the use of elements which are in mechanical connection with the contact switches. The interlocking coils of these relays are disposed in parallel. For this reason, the arrangement affords various drawbacks which are inherent in this particular method of mounting. The invention to be set forth hereunder is intended precisely to obviate these drawbacks.

In consequence, this invention relates to a device for the automatic starting of continuous or alternating current motors by means of contact switches and independent acceleration relays. Each of the acceleration relays is interlocked without the use of any elements which are in mechanical connection'with the-contact switches. This invention relates secondarily to a form of construction of acceleration relay corresponding to the abovementioned conditions, without the use of elements in mechanical connection with the contact switch. In the starting device according to the invention,

' in series with a minimum action relay,.and

also an additional resistance adapted for variations of current according to the number of coils inserted at each instant in the circuit.

The accompanying drawing which is given by way of example sets forth the principle of this invention.

Fig. 1 is a diagram of the connections'of the proposed automatic starting device, ap plied to a continuous current series motor with reversible operation and without braking.

Fig. l" shows a detail of Fig. 1.

Fig. 2 shows a modified form of the upper part of the preceding diagram; this form comprises a single minimum relay; the letters 9, B3 and h indicate the points of Fig. 1 whereto are to be connected the corresponding conductors.

F-g. 3 represents a section on the axis of the acceleration relay in use, the interlock ing coil being supposed to receive current at the given tension, whilst the relay is interlocked, that is, immobilized in the open position.

Figs. 4 and 5 show modified forms of the connections.

In the diagram Fig. 1, the various apparatus employed are represented by the following designations:

(it-C contactors for forward motion.

C. .C, con-tactors for back motion.

C to U contactors for starting.

Es series exciting winding of the motor.

E Z s braking electro-magnet in series (if required).

F F fuse plugs.

F F fuse plugs.

I I main switches.

I armature of the motor.

It D starting resistance, connected to the contactors at R, R, R, R

972 master controller.

R e a acceleration relay with the contacts 0' (Z 6 7 connected to the fixed contacts 0 d c 7 of the master-controller.

BM R'M overload relays.

Rm Rm, under voltage relays.

B8 blow-out coil of the master-controller.

RaRar. additional resistances.

The contact switches are of the shunt type and are diagrammatically represented by their control coil 52 the blow-out coil in series with the main contacts 54 and 55 (Fig. 1) and the auxiliary contacts 56, 57 which are separated when the contact switch is open. The closing of each contact switch takes place by a clockwise rotation about the pivot 58 of the armature. It should be observed that the auxiliary contact 56 is insulated from the main circuit which is indicated by a heavy line (Fig. 1). The manipulating device or controller m is shown in developed length with five positions forward motion (to the left) and five for the back motion (to the right).

The stationary contacts 04 a, 0, (Z, c, f, g, g, are shown opposite the dead point line of the manipulating device, or the zero point. The switch I controlling the main circuit shown in heavy lines, and the switch I controlling the manipulating and i11terlocking circuit, shown in fine lines, are connected to sources of current which are generally distinct and have different voltages, but which may however be common. When not used, these switches are open, and the contacts 59, 60 controlled by relays RM and RM are closed; the contacts 61, 62 controlled by the relays Rm, Rm, are open; the contact switches C, to C are open, and the secondary contacts 43, 46, 56, 57 controlled thereby are open; the contacts 6 (Z 0 f of the acceleration relays are closed.

The operation of the device is as follows.

Let it be supposed that the main switches I I are closed, and that it is desired to produce the forward motion of the motor. In the interlocking circuit, the current proceeding from the positive pole of the lines by the wire 30 will pass: through the additional resistance Re, the fine. wire coils 16 of the acceleration relays, and reaches the negative pole through 31, 32,.the minimum relay Rm, 38, 60, 39, 59 and 40. The two minimum relays Em and Rm, will be closed successively, since the circuit is closed through 34, R64 Ran 35, Be, y, g, 36, 37, 61, 38, 60, 39, 59 and 40. At the same time the acceleration relays are held open by reason of the passage of current in all the coils l6; and the contacts at 0 cl 6 f are maintained open.

Should it be desired to dispense with the relay Rm and of the additional resistance thereof Ra, these may be suppressed. In this case the interlocking circuit controlled by the manipulator is connected in series with the relay Rm as shown in Fig. 2. The cylinder of the manipulator is brought into the forward position 1, and the operating current passes as follows: 30, 41, the coils 52 of the contact devices C C 42, a the strips 63 to 68 of the manipulator, B8, 35, 62, 37, 61, 38, 60, 39, 59 and 40. The reversing contact switches C, C, will close, and the current is thrown on the motor through F RM, '0 I, (1,, Es, R R R R Ito, all the coils I, of the acceleration relays, E'Zs, RM and 15",. The motor will start with all the resistances RD in circuit, as well as all the main coils 14 of the acceleration relays. These latter will attract their armatures and will thus reinforce the action of the interlocking coils 16 up to the moment at which, the electro-mo'tive force of the motor having increased by reason of the acquired speed, the current will fall to a determined minimum value. At this moment the attraction of the main coils 14 will be insufficient to maintain open the auxiliary switches c d e f, but as already observed, these switches are interlocked by the action of the coils 16. They are unable to close except when released by the short-circuiting of their fine wire coil 16. 1

Such is precise'l the case for "the auxiliary switch 0. when the contact device C, is closed, the auxiliary contacts thereof 43 are connected together and the fine wire coil of the first acceleration relay Rea is short circuit/ed, consupiently, this relay will close the switch '0'. f at this moment We bring the manipulator into the position '2 for forward motion, the control current will pass through the contact switch "0,, by way of 30, 45, the coil 520i C 6 4i, 0, 64, 65, 66,167, 68, 69, g, 36, 37, c1, 38, c0, s9, 59, 40. The contact switch 0 which was hitherto open, will now close, thus shortcircuiting the section R0 13 0f the starting resistance, and the sudden increase of current resulting therefrom will cause the armature of the second acceleration relay Rea to remain in the raised position and the auxiliary switch d to remain "open. But since the closing of the contact switch C, has also short-circuitedthe fine wire coil of the second relay .Rea the armature of this relay may now fall and close the switch 0? as soon as the motor speed shall have increased. The control current will therefore pass through the contact switch C as soon as the manipulator is placed in position 3. The starting is pursued in this manner until the closing of the last contact switch G has cut out of the circuit the last section R R of the starting resistance. Starting will be efiected in exactly thesame conditions if the lever of the manipulator is brought at once and by a single movement into the position 5 for forward motion.

To stop the motor, the cylinder of the manipulator is brought back to the zero position. The control current is successively broken in the difierent contact switches, thereby opening the latter and throwing the starting resistance gradually in circuit; at "the same time the acceleration relays are again held open, all these movements being in the contrary sense to the order followed for the starting. For the reverse motion, the cylinder of the manipulator is brought into the position 1 for back drive, the control current now passes through the shunt coils of the contact switches used for reversal C C this reverses the main current in the motor armature, and b connecting the auxiliary contacts 46 of 0,, it also releases the first acceleration relay Rea which will provide for the closing of the starting contact 0 as soon as the manipulator is brought into the position 2 for rear motion, provided the motor shall have reached a sullicient speed to allow the value of the current to fall to a. minimum. The starting will take place in the normal manner, that is, without release of the maximum relays, irrespectively of the manner of operating the controller handle. In this manner, when the motor is at full speed in one direction, the operator may without inconvenience suddenly bring back the controller handle to the last position for back drive.

The manipulator may naturally be replaced by a simple switch button or like device used for automatic starting such as switches employed at the end of the stroke, floating switches, and the like. In this casethe connections-can be modified for instance as shown in Fig. 5. Instead of being connected to a manipulator such as m (Fig. 1), the right hand terminals of the contacts 0 cl 6' f are connected together and are also connected by a wire 72 to the pivot 73 of a two-way switch 74 for closing the locking circuit either by way of 12 through the windings of the relays C, C for forward drive, or again by way of 48 through the windings of the rear drive relays C C The same wire 72 is connected to the two fixed studs of the contact 62. In this case the wires 35 and 36 of Fig. 1 are. suppressed. It is obvious that instead of the two-Way switch 74, the arrangement may use two distinct push buttons or two contacts of any suitable kind.

Since the relay for minimum action Rm is in series in the circuit of the locking coils 16, it will act at once (or will not close). if wire of any one of the locking coils should be cut. The operation of the motor will thus be impossible if the locking circuit is not in good condition.

It is observed:

1.That the opening of a contact switch necessarily efl'ects the opening of the auxil- .iary switch of the acceleration relay subordinated to the same.

2.-That the closing'of the contact switch permits but does not necessitate the closing of the same auxiliary switch, as just stated.

'3.The order of opening and closing of the contact switches is always identical and well determined.

e.The rapidity of operation is of the same order as for mechanical interlocking. It cannot be accelerated, since an element is unable to act as long as the main current remains below a given limit as determined by the adjustment of the preceding element, but it. may be retarded as desired by the handling of the manipulator. I

The said device affords the following advantages over the devices for mechanical interlocking.

1.-No mechanical. adjustment is required between the contact switch and the acceleration relay used therewith; the contact switch is simplified by reason of the suppression of .rnechanical connecting elements.

2.--The acceleration relays may be mounted at any point on the board and can be used with any type of contact switch either with swinging armature or with solenoid core.

liein the majority of cases, one of the acceleration relays can be dispensed with; in fact for the whole outfit of reversing contact switches, a single relay will suffice, whilst the mechanical interlocking device requires two relays.

The present invention will also afford as compared with the aforesaid electric interlocking device, wherein the interlocking coils are mounted in shunt, the advantage of a greater safety, arising from the following conditions:

1.-The use of a winding of heavier wire which is consequei'itly less expensive, and of a lower tension between the turns.

2.-A better preservation of the auxiliary contacts from the fact that instead of being oliiliged to break the circuit of the coils at a. high tension, they are only required to shortcircuit coils having a. relatively low tension.

3.The greatest possible elimination of the retardation taking place in the operation of contact switches by reason of the self-induction of the locking circuit, since the series mounting of the coils in this circuit will permit of reducing this self induction.

4-.The mounting of the minimum relay Rm in series with the locking coils, in such manner that should the wire of one of the said coils become broken, this will auto matically open the control circuit. No absolute short-circuit can thus take place should the wire of the coil of the last acceleration relay become broken.

Where a considerable number of contact switches and acceleration relays are used, there may be added to the supplementary resistance Ra an auxiliary resistance Ra, Fig. at, for limiting the consumption of current and the heating of the said resistance. In this case the connections relative to the contact switch G are modified as follows.

The said contact switch is provided in the same manner as for the other contact switches with the auxiliary cont-acts TO and 71, but the movable contact 70 is so disposed as to becomeseparated from the fixed contacts 71 when the oscillating armature is attracted by the respective coil 52; but when the contact switch is open, the contacts 70 and-71 come together and short-circuit the resistance Ra; the latter is thus placed in series with the coil Ra and the contact switch C is closed, thus reducing the current in the interlocking circuit when the resistance thereof is reduced by reason of the closing of all the switches cl 6 The acceleration relay for continuous current, Fig. 3, comprises. a cast iron frame 11 of U-shape orthe like and secured directly to the board by the screws 12, having screwed into the upper branch thereof a. fixed core 13 ofmagnetic metal, whose lower end is situated in a cylindrical aperture formed in the lower branch of the frame, leaving a certain fixed air-gap, and comes flush with the bottom of the said frame. The core 13 is provided with a solenoid 14 carrying the main current. The said core is enlarged at the top and has secured thereto a steel bell 15 containing a coil 16 or interlocking coil, having a fine wire winding whose ends are shown at 16. The portion of the core between the coils 15 and 16 is made hollow, being bored out to a diameter equal to the internal diameter of the coil 16. In the recess thus formed is disposed a thin brass tube 17 having 1novable therein a core 18 of magnetic. metal. mounted on abrass rod 19 extending through the core 13 and the cover'15 and through two rings or bushings 20, 21 of a non-magnetic metal serving as guides at each end. A washer in nonmagnetic metal 22 is interposed between the cover and the core 18 to obviate all danger of sticking.

To the brass rod 19 is secured by a pin screw-threaded sleeve 23 of brass having movable thereon an armature 2a in mag netic metal whose height is so adjusted as to provide between the armature and the bottom; of the frame 11 a determined airgap. The position of the said armature is provided for by the brake 25. Below the threaded sleeve 23 the; rod 19 carries a contact disc 26 which in the inoperative position is caused to bear upon two fixed contacts 27 forming part of the control circuit. The disc 26 is insulated from the rod 19. As above set forth the coil 16 is supplied by a special locking circuit independent of the manipulator. All the locking coils 16 are in circuit with an additional resistance Ra and are excited when all the contact switches are open at the beginning of the operation. They are placed successively in shortcircuit in an order which. is determined by the closing of the contact switches, which annuls their action. It is evident that the same result may be obtained without departing from the principle of the invention, by opening their circuit instead of shortcircuiting.

The said device is in every respect applicable to the use of alternating current, except for the sole modifications in detail as required by the nature of the current, both as concerns the number of phases of the main current and as concerns the construction of the contact switches and the acceleration relays for the purpose of obviating the ex cessive heating of the parts. All competent persons engaged in construction will be familiar with such modifications, and no further mention need be made of the same.

Claims:

1. In an automatic starting device for electric motors, the combination with starting resistances included in the main cirsuit of the motor and contactors of the shunt type used for gradually short-circuiting these resistances at starting or for putting them into circuit at the moment of stopping; of accelerating relays controlling the flow of current into the shunt coils of the respective contactors, said relays comprising movable contacts, an armature connected with said contacts, a thick wire coil traversed by at least a portion of the main current of the motor, and athin wire locking coil acting upon the armature of said relay in the same direction as the thick wire coil,

the circuit of each thin wire coil being itself controlled by the preceding contactor according to the order followed for the starting, and all the locking coils being connected together in series.

2. In an automatic starting device for electric motors, the combination with starting resistances included in the main circuit of the motor, and contactors of the shunt type used for gradually short-circuiting said resistances when starting or for putting them into circuit at the moment of stopping; of accelerating relays controlling the flow of current into the shunt coils of the respective cont actors, said relays comprising movable contacts, an armature connected with said contacts, a thick wire coil traversed by a portion of the main current of the motor, and a thin wire locking coil acting upon the armature of said relay in the same direction as the thick wire coil, the circuit of each thin wire coil being itself controlled by the preceding contactor according to the order followed for the starting, all the locking coils being connected together in series, and rendered 1 inoperative through short-circuiting of their respective windings. In testimony that I claim the foregoing as my invention, I have signed my name in presence of two subscribing witnesses.

PAUL HENRI FREDERIC LAMBERT.

Witnesses:

CHARLES JPH. ALB. EHOUVENOT, MAURICE Roux.

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