US1638372A - Best available copy - Google Patents

Description

Aug. 9. 292'?v G E. ZETACK rms Emma-tr comma AND APPARATUS THEREFOR F l y 1925 2 Sheets-Sheet l [rive/7502" 660C363 E Slack, 2/, f 42% His Attorngy Aug. 9, 1927.

G- E STACK TIME ELEMENT CONTRGL' AND APPARATUS THEREFOR 1-3heets--5heet z Filed May 3. 192 5 we ,7 w

his A if Patented Aug. 9, 1927.;

UNITED STATES PATENT orrlcs.

GEORGE E. STACK, OF BALLSTON SPA, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

TIME-ELEMENT CONTROL AND APPARATUS THEREFOR.

Application filed May 8,

My invention relates to improvements in the control of the operation of various de vices by introducing a time interval between the operation of various parts of the devices.

One of the principal objects of the invention is to provide a reliable and inexpensive time element device, Various devices have from time to time been proposed and adopted for obtaining time interval control, such, as for example, dash pots of various types, trains of gears with escapements, trains of gears driven by motors. or otherconstant running devices, etc., but former devices have been expensive when made so as to be re- 16 liable. The dash pot, which is usually the least expensive, even when carefully made is not accurate, since the time lag introduced will vary with vaiious conditions, such as temperature, humidity, wear of the parts, etc. 7 4

' One of the objects of the invention is to eliminate gears, dash pots, and the like, and to reduce the number of the moving parts of the time element device to a minimum con- 26 sistent with good practice.

A further object of the invention is to pro vide a time elementdevice which is so simple'in construction that the ordinary mechanic or electrician will readily understand the principles involved, so that he may read-. ily adjust the device for the desired time interval.

A further object of the invention is the provision of an improved time element device which is very quickly and easily reset-s0 as to be ready for the next operation in introduclng a time lag in the successive operation of various devices,

A still further object of the invention is to provide a device which is so simple and rugged in construction that it is not necessary to protect the device by covers or enclosures, the device being capable of subjection to the same service and operative conditions as other control apparatus, such as.

- contactors, switches, relays, and the like.

n carrying the invention into effect in one form, I provide electroresponsive means which is arranged to be connected to the member to be controlled so as to alternately hold and release the controlled member and permit. the same tomove step by step from one position toward another. The electro- 1923. Serial N0. 36,458.

responsive means may take the form of an electromagnet with an armature which is alternately attracted and released in accordance withthe frequency of the current supply for the winding of the electromagnet, or

the arrangement may be such that the attriiction of the armature ,deenergizes the winding of the electromagnetand the release of the armature again energizes the electromagnet, or the arrangement may take other forms as will be understood by those skilled in the art from an understanding of the indrawings which show one form of the invent-ion for the purposes of illustration, and in which Fig. 1 is a plan view of a time element devicein accordance with the invention controlling an auxiliary switch of an electromagnetic switch or contactor; 'Fig. 2 is a perspective view of the time element device of Fig. 1; Fig. 3 is a perspective view of a detail of the time element device showing a part of the connections between the controlled auxiliary switch member and the time element device; and Fig. 4 is a very simplified diagram of a time element system of motor control in accordance with the invention.

Referring to the accompanying drawings, the time element device 10 is indicated as an auxiliary switch which is controlled by the main electromagnetic switch mechanism comprising the operating electromagnct 11 with its movable armature 12 connected'to the switch shaft 13 on which movable contacts 14, 15 and -16 are mounted so as tobe simultaneously operated. The blowout arc chutes 17, 18 and 19 are rovided for rupting the arcs formed etween the movable contacts 11, 15 and 16 and their respective stationary contacts. The switch mechanism 14, 15 and 16, the common operating shaft 13, and the electromagnetic operatingv means comprising the'o perating magnet 11 position by a pull transmitted through the operating shaft 13. The arm 21 connected member 20 as indicate with. its operating armature 12 form a well known construction and one which will be readily understood by those skilled in the artwithout further description.

The time element device 10. which is shown in more detail in Fig. 2, comprises a pivotally mounted movable switch member 20.which is biased by gravity to the open position and is operated to the closed to the closed position is retarded by meansof the timing arrangement which I'shall now describe. The arm is connected to the switch member 20, as shown in Fig. 3,

and one end of this arm-carries a movable magnetic member or armature 26 of an elec tromagnet which is provided with a coil 27 disposed on a core 28. The armature 26 is mounted in the one end of the arm 25 inv such a manner that the armature is capable of a relative movement with respect to the arm, and thus with respect to .the switch member 20. and yet the armature is carr ed along by the arm .25-when the arm is released'by the armature. vThe armature 26 is provided with a'projection 29 which projects through a suitable opening in the arm 25 so as to interlock the armature with the arm. The arrangement is such that when the switch member 20 is urged to the I 'ised position by reason of the force applied through the spring 23 from the shaft 13. the arm 25 will be momentarily held by the armature 26 because of the fact that this armature will be attracted to the end of the pole 2801: the electromagnetic timing device. It is presumed that thecoil 27 of the timing electromaqnet is connected to an alternating current supply circuit, so that the magnetism of the core 28 will be periodically reversed in accordance with tlrfrequency of the supply circuit. This will cause a chattering of the armature 25; that is, the.

armature 26 will be periodically attracted and released in a definite periodicity in accordance with the frequency of the supply circuit. While the armature is attracted. it will magnetically hold the arm i25,;and thus the switch member-20, and when the armature is released. the arm 25; will be permitted to move a short distance until the armature is again attracted. The armature is thus caused to skip it" a bubstantially definite periodic step by ste manner over 4 the pole piece 28, periodical y holding and releasing the arm 25.

The time lag between the closing of'the main switch contact mechanism 14, 15 and 16 and the closing of the auxiliary switch contact mechanism will be determined by the length' of time required for the armature 26 to skip over the end of the pole ieoe 28 in the manner previously described This time, may be easily adjusted by turningithe adjusting screw 30 so as to vary the initial position of the arm 25. It will be observed .that the movement of the switch member 20 to the closed positionwould be a continuous and uninterrupted movement if it were not for the timing device, but with this timing device the movement of the switch It] will 'be observed that while. I have shown my invention in connection with an arrangement intended primarily for use on! alternating current circuits. I would have it understood that'the invention is not necessarily limited to an alternating current device. and may be applied to a direct current' system as well. it merely being necessary to 05 rovidc some suitable means for interrupting the current in the magnet Winding: 27 in accordance with the attraction of the ormature 26 and to reenergize this winding 7 in accordance with the release of the armaup turc 26 so as to 'thus obtain a substantiallv definite periodicity of the step bv step advanceot the armature and switch member. Such a, modification will be well understood I bv those skilled in the art, and it is believed that a further description is unnecessary.

Referring to Fig. 4, it will be seen that I have disclosed my invention in connection with an arrangement for stdrting an alternating current three-phase wound rotor type/J of electric motor. Referring to the figure, the electric motor M is arranged to be connected to the alternating current supply circult by means of theclectromagnetic line switch or cont-actor 31. The master switch 32 is provided for controlling this line contactor and the accelerating cont actors 33 and 34, as well. When the. line contactor 31 closes, it puts the auxiliary switch member 20 under a bias to the closed position, but

- previously explained.

this switch member is retarded in its movement to the closed posit-ion by means of the tnneelement deyice previously described, the coil 27"- 'of the time element device being s multaneously energized :with the energizetlon of the-grinding of the line contactor 31. The auxiliary switch member 20 will skip or move step by step toward the closed posi-- tion in an interval of time which may be predetermined, aiid when the switch member makes engagement with its stationary contact, the accelerating contactor 33 is ener gized to close so as to short circuit the resistors B in the rotor circuit of the motor. When the accelerating contactor 33 closes, it places the auxiliary switch member 20" under a strain to the closed position, but this, switch member is restrained in the manner After the switch member 20 has movedstep by step to the closed position, the accelerating contactor-i34 is energized to close and short circuit the besistors R and thereby connect the motor for full speed operation.

It will be observedt-hat time element device is very simple and rugged in oonstruction'and has relatively few parts, which are easily made. It will also-be observed that the time element device as a whole is of the same natureas the switch mechanism'with which it cooperatesso that this time element device does not need-to be protected by a cover or by an enclosure; and it willalsosbe noted that thedevice is very easily adjusted. When the main switch contacts with which the time element device is associated are opened, the auxiliary switch of the time element device will move directly to the full open position, since its movement in this direction is unrestrained and the device will be immediately reset for the next operation.

In accordance with the provisions of the patent statutes, I havedescribed the principle of my invention, together with the apparatus which I now consider to repr nt the best embodiment thereof but I desire to have it understood that the apparatus is only illustrative and that the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

l. A time element device. comprising a controlled member which is urged from one position toward a second position, and electroresponsive means having two relatively movable parts. one of which is carried by the said member and cooperates with the other part to alternately magnetically hold and release the said member and permit the member to move continuously forward in a step by step manner to the said second position when released and thereby introduce a substantial time interval before said controlled member reaches the second position.

2. A time element device for retardingthe action of a controlled member which is urged from one position toward a second osition,

comprising electroresponsive means avinga magnetic movable member which isalternately magnetically held and released and which is carried by the said controlled menther to alternately. hold and release the same and thereby introduce a substantial time interval before said controlled member reaches the second position...

3. A time element device comprising a Bil controlled member which is urged from one position; toward a. second-position, an el troma et having a core and a magneticmovab e member which is ."alternate y at- 'tracted to and released. from the said core,

"and connections between the said magnetic member and the said controlled member whereby the said members move in a step by step succession of continuous forward move ments with reference to the said core-in ac cordance with the release of the magnetic member and thereby introduce a substantial time interval before said controlled member;

reaches the second position.- I

4. A time element device comprising a controlled member which is urged from one position toward a second position, an electromagnet having a core and an armature which is'connected to the said member to be moved thereby across the end'of the said core and impart a step by step continuous forward movement to the said member as the armature is attracted to and released from the said core, whereby a substantial interval of time is introduced ,in the movement of the member Erom'the first position to the second position. 5. A time element device comprising a pivotally mounted control member-which is -'-urged to move in one direction about its pivot from one position to a second position, an electr'oma'gnet having an armature which is alternately attracted and released, and connection between the said armature and the said controlled member whereby the member and the armature move in a succes sion of step by step forward movements about thepivot of the member in accordance with the attraction and release of the armature to thereby introduce a-substantial interval of time in the movemen'tof the member to the said second sition. ,j I

6 A time eement device for electric switches comprising a switch member, and means for urging said member from one position to a second position, an electromagnet having an armature which is alternately attracted and released ant which is connected to the said switch member to alternately restrain the movement of the switch member in response to the urge of said means and permit the switch member to advance step by step from the first positiontoward the second position as'the armature is attracted and released, whereby a substantial interval of time is introduced in the movement of the switch member from the first to the second position.

7. An electric switch comprising an operating clcrtromagnet, main switch contact mechanism operated thereby, an auxiliary switch which is urged toward the closed position by [he said operating electromagnet, and a restraining electromagnet fordelaying the closing of the auxiliary switch for a definite interval of time after the operation of the said main switch contact mechanism, the said restraining electromagnet having an armature which is alternately attracted and released and is connected to the said auxiliary switch to impart a; step .by step move ment thereto as the armature is attracted and released.

-8."An electric switch comprising main switch contact mechanism, an operating elec tromagnet tlierefor, an auxiliary switch, a resilient connection between the auxiliary switch and the operating 'electromagnet through which force is applied to close the auxiliary switch, and means for dela ing the closing of the auxiliary switch' a do to the closed position in accordance with the attraction and release of the magnetic mov able member.

9. A time interval device for controllingelectric circuits comprising" an electromagnethaving an armature which is alternately attracted thereto and released therefrom in a definite periodicity when the. windingof the elcctroma-gnct is energized by a current which increases and decreases in a definite periodicity, a switch contact movable between two positiops, a device connected with said contact for urging the contact to move immediately from the first of said positions to the second thereof, and a mechanical connection betweenthc said contact and said ite interval after the closing of the main -switch armature permitting of movement of thearmature with respect/to the contact where by when the contact is urged b said device from the first of said positions to the second thereof the said contact is alternate 1y restrained and released by the armature with a definite periodicity as the contact advances in response to said'urge' so that an appreciable time interval is introduced before the contact reachessaid second position.

10. A time interval device {for electric circuits comprising an electromagnet having a core "and an armature which is alternately attracted to andrele'ased from the core in a substantially definite and constant periodicity, a switch'member connected to said armature to be restrained thereby in moving from one position to a second position, the

connection between the switch member and the armature permitting relative movement of the armature with respect to the switch member, whereby when the switch member is urged to move directly forward from the "first po's'i'tiomto the second position the said armature modifies the direct forward movement 'into a 'succ'essionoi step-by-step forward movements'of a definite andconstant periodicityasithe' armature is attracted to and'released from said mire"- to thereby introduce a substantial' time interval before the member reaches zthe second position.

11. An electric switch having main switch contact mechanism, an'operating electromagnet therefor, an auxiliary switch, a resilient connection betweensaid electromagnet and said switch through to close. theswitc 'whic h' force is applied when the electromagnet is energized to close said contact mechanism,

a retarding elect'ronjiagnetfor said auxiliary switchhavmg a-stationary core with a winding disposed thereon andfa movable armature which-moves across one end of said core and 18 connected with said auxiliary switch to move with respect thereto as the armature is alternately attracted to and released from.

said core, wherebyza delayed step by step movement ofsaid auxiliary switch to the closed position is'- effected. I Y

In witness whereof,- I have hereuntoset my hand this 2nd day of May, 19 23.

GEORGE- E. STACK.

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