US1293532A - Controlling means for electric motors. - Google Patents

Description

. G. PECK.

CONTROLLING MEANS FOR ELECTRIC MOTORS.

APPLICATION FILED SEPT.25| 1916.

Patented Feb. 4, 1919.

2 SHEETSSHEET I.

F. G. PECK.

comomwe MEANS FOR ELECTRIC MOTORS.

APPLICATION FILED SEPT-25.1916- Lg93 53g Patented Feb. 4, 1919.

2 SHEETSSHEET 2.

FREDERICK c. PECK, or PHILADELPHIA,

PENNSYLVANIA, ASSIGNOR OF ONE-HALF TO JAMES B. WILSON, OF PHILADELPHIA, PENNSYLVANIA.

' CONTRPLLING MEANS FOR ELECTRIC MOTORS.

Specification of Letters Patent.

Patented Feb. 4, 1919.

Application filed September 25, 1916. Serial No. 121,938.

To all whom it may concern:

Be it known that I, FREDERICK G. Peon, a subject of the King of Great Britain, residing at Philadelphia, in the county of Philadelphia and ,State of Pennsylvania,

have invented a new and useful Improvement in Controlling Means for Electric Motors, of which the following is a specification.

This invention relates to controlling means for electric motors, and more particularly to means for changing the field I tion shown,

circuit of a motor so as to increase or decrease the field strength.

The objects of the invention are to produce controlling means of this kindof im proved construction in which the field current of a motor is controlled by means of a snap switch actuated by a part of the controller; also to provide a snap* switch of improved-construction which is particularly ada ted to housed in connection with a control or or the like for controlling the motor fieldcurrent. a

In the accompanying drawings: Figure '1 shows diagrammatically a motor controller and the circuits controlled ing the thereby, and a snap switch embod ation U0 invention arranged in operative the controller. I

. Fig. 2 is a detached View of the movable member of the motor controller.

Fig; 3 is a side elevat'on of the snap switch detached from the controller.

Fig. 4: is a top plan view thereof.

Fig. 5 is a sectional elevation on line 55, Fig. 4, showing the parts of the switch in different positions.

Fig. 6 is a detached perspective view of the actuating member of the switch.

Fig. 7 is a sectional end elevation on line 7-7, Fig. 4.

The motor controller as shown diagrammatically in Fig. 1 includes a contact strip A which is ada a contact strip a or any one of a plurality of contacts or short strips a, a contact strip A, which is adapted to be connected with any one of a plurality of contacts or short strips a or with a contact stripe, and a contact member B which, in the construcis adapted to be moved lengthwise of the contact strips for connectingthe strips A A with the contacts a a and a a respectively. a represents insulated d to be connected-with plates or segments with which the movable contact member may be placed into engagement for interrupting the supply of current to the motor.

The movable contact member B, as shown, consists of a handle portion 6 on which are mounted two connectors or bridge members 6 btinsulated from the handle I). The connector b is adapted to connect the contact strip A with the strip or piece a or with the contacts a and the connector 6' is adapted to connect the contact strip A with the contacts a and the contact strip a. All of these parts may be of any usual or suitable construction and of themselves constitute no part of this invention.

The contact strip A is connected by means of a conductor 0 with any suitable source of power, such, for example, as a storage battery C, and the contact strip a is connected by means of a conductor 0 to the armature D of the motor. The contacts a are connected by means of conductors c to a suitable armature resistanced which is connected by means of a conductor (1 to the contact strip a. Consequently as the connector bof the movable contact member movesfrom left to right in Fig. 1, the full armature resistance 03 is first placed in serice with the circuit connecting the motor armature with the source of power, and as the movable member of the controller moves to the right this resistance is gradually decreased until the connector 6 connects the contact strips A. (1*, which short circuits the armature resistance. The other terminal of the armature is connected by means of conductors d and c to the source of power C.

The contacts a are connected by means of conductors c with a group of resistance units E, and the contact plate or strip a is connected by means of a conductor 6 with one of the contacts a", through which current passes. from the battery when the contacts a or the contact strip a are con nected with the contact strip A by means contact strip A, so that no resistance is inserted into the field circuit. When the movable contact member connects the first of the contacts a with the contact strip A,

a small resistance is into the field c1rcu1t, which reslstance is lncreased as the movable conta-ct'member is moved to the right. Any other connections or circuits between the parts of the controller and the motor, battery and resistance devices may be employed.

In order to obtain a still greater variation in the speed of the motor, means are provided for connecting the coils of the field circuit either in series or in parallel.

In changing from the series connection to the parallel connection, or vice versa, while the armature is connected with the source of current supply, it is desirable that this change should be instantaneous so that the field circuit is not interrupted for any appreciable length of time while current is flowing through the armature. In order to accomplish this result a snap switch is provided which is actuated by the movable member of the controller in such a manner that the field coils of the motor will be connected in parallel when the motor is tact g suitably insulated from the switch.

member, and at its other end with two contacts g 9 which also are mounted on and insulated from the movable switch member G. The movable contact -g' is adapted to enga e with a fixed contact f mounted on and insulated from the base F when the movable switch member is in the position shown in Fig. 3 and in fulllines in Fig. 5, and the movable contacts g g are adapted to engage with fixed contacts f f also mounted'on and insulated from the base F when the switch member is in-the position shown in dotted lines in Fig. 5. The contacts g g and 8 are preferably mounted on strips g of. spring metal or resilient material which are secured on the movable switch member and which yieldingly press the contacts of the movable switch member into engagement with the fixed contacts of thebase of the switch. I

In order to move the switch member G rapidly from one position toanother, a switch actuating member H is preferably provided which, in the construction shown,

comprises an intermediate or. body portion it having upwardly extending arms 7:. h which are pivoted at their upper ends at g on the posts f of the base of the switch, and downwardly extending arms hf 71. which extend through a slot hin the base into a position to be engaged by a part of the movable member of thecontroller, the ends of the slot limiting the movement of the switch actuating member. The switch actuating member H is connected with the movable switch member by means of a coil spring I secured at its lower end to a lugz' on the ating member from one position to the other,

the movable member B of the controller is provided with an'extension or lug i which is adapted to engage the arm 72. when the movable member is moved to the right in.

Fig. 1 to throw the switch into position to connect the motor fields in series, and to engage the arm 71. when moved to the left in Fig. ,1 to throw the. switch into the other position in which the motor fields are connected in parallel;

The connections between the terminals of the field controlling switch and the motor fields are preferably made as follows:

In the motor which is shown diagrammatically in Fig. 1, the field coils are divided into two sets, groups or coils K K which may be either connected. in series or in parallel by means of the field controlling switch. One terminal of the coil K is connected by means of a conductor is with the fixed contact f and the other terminal of this coil is connected by means of a conductor k to the fixed contact f. The terminals of the other coil K are connected by means of conductors k k respectively with the contacts 9 of the movable switch member G; The conductor is is connected by means of a conductor 70* to the fixed contact f of the switch and the movable contact g is connected by means of a conductor k to the conductor k Consequently when the switch is'in the position indicated in Fig. 1, the two coils or groups of coils K K of the motor field are in series, and

when the switch is in the other position the Other two coils are connectedin parallel. connections between the motor fields and the switch may be used if desired.

By means of the apparatus described a cdnsiderable variation in speed of the motor can be obtained, since the motor when starting with the movable member of the controller in the first position has the coils or group of coils of the field circuit-connected in parallel and a resistance is inserted in the armature circuit. controller handle has been moved to the right in Fig; .1, the fields are in series and the entire field resistance is in the field circuit, so that the motor runs at its maximum speed. In intermediate positions the speed of the motor can be regulated as desired. The apparatus is simple to operate since the coils are automatically placed into either the series or parallel position by means of the movable part of the controller, so that no adjustment or manipulation other than the movement of the controller itself is required. The apparatus is particularly desirable for use in connection with electric motor vehiclessince it makes it possible to use a shunt motor, owing to the fact that by placing the motor fields in parallel a heavy starting torque may be produced. The apparatus may, however, be used for other purposes. The field changing switch is shown in the construction illustrated as applied, to a shunt motor, but it will be understood that it is not intended to limit the use of this switch to shunt wound motors since the switch could perform the same function on series or compound wound motors.

I claim as my invention:

1. The combination with a source of electric power and a shunt-wound direct current electric motor havin a field winding consisting of a plurality ot coils, of a controller for supplying a gradually decreasing flow of current to the motor field, and a switch by means of which said fields are connected in parallel when the motor is starting and which is actuated by the controller before the current in the motor fields has reached its minimum strength. for connecting said fields in series.

2. The combination with a source of electric power and a shunt wound direct current electric motor having a field winding consisting of a plurality of coils, of a controller for regulating the flow of current to the motor field a switch separate from said controller and by means of which said field coils are connected in parallel when the motor is being started, and a part on said controller adapted to actuate the switch for connecting the coils of the motor field in series before the current in the motor fields has reached its minimum strength.

3. The combination with a source of elec tric power and an electric motor having a field winding consisting of a plurality of coils, of a controller for regulating the fiow of current to the motor field and having a lVhen the movable tric part which is movable in one direction to decrease the strength of the current flowing through said motor field, and a switch separate from said controller which isactuated by said movable part of the controller at an intermediate portion of its path of movement in a direction to decrease the field current, and which connects the coils of the 5. The combination with a source of electric power and an electric motor having a field winding consisting of a plurality of coils, of a controller for regulating the How of current to the motor field, and a snap switch separate from said controller and actuated by the controller at an intermediate portion of its path of movement for connectmg the field coils in series and in parallel.

6. The combination with a source of electric power and an electric motor having a field winding comprising a plurality of coils, of a motor controller for regulatin the flow of current in the motor fieldan having a movable part, of a switch for conmeeting said fieldcoils either in series or in parallel and arranged in a position to be engaged by said movable part as the same moves past said switch, said switch comprising a movable switch member, a switch actuating member adaptedto be engaged by said movable part, and a connection between said switch actuating member and said movable member for causing said movable switch member to be quickly'moved from-one position to another after said switch actuating member has moved through a predetermined distance.

7. The combination with a source of electric power and an electric motor having a field Winding consisting of a plurality of coils and an armature, of a controller for regulating the supply of current to said armature and said field coils, and a switch actuated by said controller when starting the motor for connecting the field coils in series after the supply of current to the armature has been brought to its maximum and before the supply of current to the field coils has been decreased.

8. The combination with a source of elecpower and an electric motor having a field winding consisting of a plurality of coils and an armature, of acontroller for regulating the supply of current to said armature' and said field coils, said controller having resistance devices adapted to be inserted -into the armature and field circuits, and a switch actuated by said controller when starting the motor to connect the field coils in series after the resistance has been cut out of the armature circuit and before the reisistance has been inserted into the field circuit.

Witness my hand, this 20th day of September, 1916.

' FREDERICK G. PECK. Witnesses:

FRANK J. LITTLE, JAMES B. WILSON.

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