US1421242A - Control system - Google Patents

Description

H. D. JAMES.

CONTROL SYSTEM. APPLICATION FILED JAN-8, 1919.

1,421,242. Patented June 27, 1922.

WITNESSES: INVENTOR W Henry 0. James.

UNITED STATES "PATENT OFFICE.

HENRY D. JAMES, 035 EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIG & VANIA.

MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- common SYSTEM.

Specification of Letters Patent. Patented June 27, 1922,

Application filed. January 8, 1919. Serial No. 270,147.

To allwhom it may concern: 7 I

Be it known that I, HENRY D. JAMES, a citizen of the United States, and a resident of Edgewood Park, in the countyof Allegheny and State of Pennsylvania, have invented a new and useful Improvement in lontrol Systems, of which the following is a specification.

My invention relates to motor-control systems and particularly to systems of the type forming the subject-matter of my eopending application Serial No. 236,937, filed May 27, 1918, in which the accelerating resistor is controlled by contactors, the closing of which is effected by relays which are in turn controlled by a coil in parallel circuit with the resistor.

The object of my invention is to provide such a system, the controlling coil of which shall be in series relation to the resistor.

According tothe present invention, the relays are designed to be successively actuated, in accordance with circuit conditions, upon successive portions of the coil becoming short-circuited by the preceding relays to close.

Figure l is a diagrammatic view of a system arranged according to my invention, and Figs. 2 and 3 are, respectively, a side and an end elevation of a relay device such as is preferably employed in connection with my motor.

Referring to Fig. 1, a motor, the armature of which is shown at 1 and the-shunt field-magnet winding at 2, is connected between line conductors 3 and 4, with an accelerating resistor 6 in series with the armature 1. v circnited upon the closing of contactors 10,

11 and 12, which respectively control re sistor portions 13, 14 and 15. The contactors 1.0, 11 and 12 are clo ed by energizing coils 19, 20 and 21, the circuits oi" which are controlled by relays 25, 26 and 27, which are respectively controlled by a coil 22, divided into three portions, 23a, 23b and 230,

the points oi connection of which are respectively connected to the contactor 10 a conductor 17 and to the contactors 11 and 12, in parallel, by a conductor 18. A switch 7 is adapted to connect the motor,the resistor and the coil 22 to the line conductors 3 and 4.

The preferred relay mechanism is shown in Figs. 2 and 3. An insulating panel 29 carries two brackets 30 and 31 supporting The resistor is adapted to be short-.

the coil 22 which, .when'energized by current flowing through it, creates a magnetic fieldior attracting an armature 32 and any desired number of additional armatures 33. A compression spring 36 is 'adjustably mounted upon a non-magnetizable rod 37 lslidably mounted in projections 38 and 39 which are rigidly connected to, or are integral arts of, the bracket 31.

v The pro- JGGUOIIS 38 and 39 serve also as pole pieces for the armatures 32 and 33, respectively.

A bar 40 is'rigidly connectedto the rod 37,

and normally engages the armatures 33. The spring 36 thus normally maintains the armatures 33 in open position, with the members 41, which are carried by these armatures, in contact with the pole piece 39. The members 41 are preferably of non-magnetizable material to prevent freezing.

The armature 32 is provided with brackets 42, which are pivotally mounted upon the bracket 30, and is normally retained in the broken-line position, (Fig. 2), by a weak spring 43. The bracket 30 supports a nonmagnetizable U-shaped member 44, between the arms of which are pivotally mounted the armatures 33, which carry, respectively, the movable contact members 45, 46 and 47 of the relays 25, 26 and 27, shown in Figs. 2 and 3 as closed. The stationary contact members 48, 49 and 50 of the relays 25, 26 and 27 are mounted upon the I insulating panel 29. Springs 51. are attached to longitudinally adjustable members 52 and to the other ends oi the members 41. The pole piece 39 is provided with longitudinally adjustable members 53to regulate air gaps 70 between these members and the correspondingfarmatures. By means of this adjustment, or by means of the members 52, the action of: the magnetic flux produced by the coil 22 may be so regulated that the armatures 33 will be operated in proper sequence.

The operation is as follows: Upon the closing of the switch 7, themotor circuit is established from the line conductor 3, through the armature 1 and the resistor 6 and the field-magnet winding 2 in parallel, the coil 22 and the switch 7, to the line conductor 4. The coil 22 is accordingly energized to actuate the armature 32 into the full-line position of Fig. 2, whereupon the armatures 33 are released from the restraining influence of the spring 36. Initially, the current is too high to permit the springs 51 to close their armatures, but as the motor accelerates, the current value decreases. When the current falls to a predetermined value, the relay 25 will be closed by its spring 51 to cause the closing of a circuit extending from the line conductor 8, by way of a conductor 28, through the relay :25, the coils 19 and 22 and the switch '7 to the line conductor 4;. The contactor 10 will, there upon, be closed to short-circuit the resistor portion 13 and also the coil portion 23a. The armature circuit may now be traced from the line conductor 3. tl'irough the armature 1, the resistor portions 15 and 14, the contactor 1O, the conductor 17. the coil portions 23!) and 230 and the switch 7 to the line conductor As the motor accelerates furtheir and the current, consequently, drops to a lower value. the relay 26 will be closed to cause the energization of the coil 20 and the consequent short-circuiting' of the resistor portion 14 and the coil portion 237). The re lay 27 will ultimately close when the current traversing the motor falls to a sufficiently low value, whereupon the contactor 12 will be closed to short-circu it the resistor portion 15. The motor will now be connected directly across the line, and the coil portion 230 will be maintained in the motor circuit to maintain the armature 32 in the actuated position illustrated in Fig. 2.

I have shown my invention as embodying a switch of particular construction, As the coil 22 is in series with the motor, and as the successive current peaks, 'lollowing; the successive short-circuitingoperations, are nearly oiequal value, I have provided for controlling the relays by currents of substantially different value by tapping the coil 22, as shown.

It will be understood, however, that the operation of my system is by no means dependent upon the use of the particular relay mechanism illustrated in Figs. 2 and 3 and that my invention is not limited to the use ()1 a series coil in the particular manner which ishercin illustrated and described. I desire, therefore. that my invention be construed as broadly as is indicated in the appended claims.

I claim as my invention:

1. The combination with an electric m0- for having a resistor associated therewith, a plurality of electromagnetic switches for controlling said resistor, and a relay for controlling said switches and having an energizing coil in series with said motor, said coil being operable to maintain said re lay open upon the closing of the circuit of said motor so long as the current traversing said circuit exceeds a predetermined value, and means comprising the first of said switches to close for shunting a portion of said energizing'coil of said relay.

2. The combination with an electric motor having a resistor associated therewith. switch for controlling said resistor and means for normally maintaining said switch open, of an energizingcoil for rendering said means ineffective to maintain said switch open under predetermined conditions, and a circuit controlled by said switch whereby a portion of said coil is de-encrgizoiil upon the closing 01 said switch.

The combination with an electric motor having a resistor associated therewith. a relay comprising a plurality of pairs oi contact members for controlling said resistor and an energizing coil 101 said relay, said pairs oi contact members being; opcra'iil'e at different degrees of force exerted by said coil. oi? means for shunting;- a portion of said. coil upon the operation ot the first pair of contact members to close.

1-. The combination with an electric notor having a resistor associated therewith and means comprising a pair oi normally opin switches for controlling; said resistor, said switches being biased to clos d positions. of a coil in series with said resistor tor maintaining: said switches open when the current traversing said coil is above predetermined values, and means for shunting; a portion of said coil upon the closing or one o1. said switches.

The combination with an electric motor having a resistor associated therewith, a pair of switches for controlling said rcsistor and means for normally maintaining" said switches open, of? an energizing coil for rendering said maintaining means el' ective or ineffective in accordance with predetermined conditions, said switches being controlled by different current values of said coil. and means ior short-circuiting a portion of said coil upon the closing of one of said switches and "for maintaining; aportion 01? said coil in circuit after the closing: of said other switch. 7

(5. The combination with an electric motor having an armature, a resistor in series therewith, a plurality of switches for shortcircuitiilg said resistor, a relay for each switch and means tor normally maintaining said relays open, of a coil in series with said resistor for rendering said maintaining means effective or ineffective to maintain said relays open according as the current traversing said coil is above or below predetermined valnes, and means for shortencuiting a portion. of said coil upon the closing of all the relays except the last to close and for maintaining a portion of said coil in the motor circuit after the closingof the last eontactor to close. H

In testimony whereof, I have hereunto subscribed my name this 21st day of Dec, 1918.

HENRY D. JAMES.

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