US2689317A

US2689317A - Electromagnetic means having a flux shifting movable pole member

Info

Publication number: US2689317A
Application number: US266931A
Authority: US
Inventors: Julius W Timmerman
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1952-01-17
Filing date: 1952-01-17
Publication date: 1954-09-14
Anticipated expiration: 1971-09-14

Description

Sept. 14, 1954 Filed Jan. 17, 1952 J. W- TIMMERMAN ELECTROMAGNETIC MEANS HAVING A FLUX SHIFTING MOVABLE POLE MEMBER 2 Sheets-Sheet l l llhll u= x, m #73 Mme/M p 14, 1954 J. w. TIMMERMAN 2,689,317

ELECTROMAGNETIC MEANS HAVING A FLUX SHIFTING MOVABLE POLE MEMBER Filed Jan. 17, 1952 2 Sheets-$heet 2 Patented Sept. 14, 1954 UNITED STATES PATENT OFFICE ELECTROMAGNETIC MEANS HAVING A FLUX SHIFTING MOVABLE POLE MEMBER Milwaukee, Wis.

Application January 17, 1952, Serial No. 266,931

4 Claims. 1

This invention relates to electromagnetic devices and more particularly to electromagnetic actuators employing means for shifting the flux path through their cores.

In a preferred embodiment of the invention claimed a new and improved electromagnetic actuator is provided which comprises a coil, a core, an armature biased to a first position and magnetically attracted to a second position upon a predetermined energization of the coil, and a pole member movable from a first position to a second position to shift the flux path through said core. The pole member may be actuated by any suitable means such as a lever, push rod, pneumatic motor or a blast of gas under pressure which is set in operation by the movement of the armature under the influence of the magnetic field of the coil. The pole member is then actuated from its first position to its second position to shift the flux path through the core and to move the armature against the magnetic field back to its first position and to lock or hold it there until the coil is at least partly deenergized.

It is, therefore, one object of the present invention to provide a new and improved electromagnetic actuator in which the armature is controlled by a force other than the magnetic field of its coil.

Another object of the invention is to provide a new and improved electromagnetic actuator in which the flux paths through its core are shifted to lock the armature in one of two positions.

A further object of this invention is to provide a new and improved solenoid actuator in which the armature may be actuated by a pneumatic means against the magnetic field of its coil and locked in one of two positions.

A still further object of this invention is to provide a new and improved solenoid actuator in which a pole member is shifted upon a predetermined movement of its armature to shift the flux path through its core.

Objects and advantages other than those set forth will be apparent from the following description when read in connection with the accompanying drawings, in which:

Fig. 1 is a diagrammatic view partly in elevation of a circuit interrupting system embodying the present invention; and

Fig. 2 is an enlarged view in axial cross section through a pneumatic control valve illustrated in Fig. 1.

Referring more particularly to the drawings by (Cl. SUP-176) characters of reference, Fig. 1 illustrates a circuit breaker including as a constructive element thereof a reservoir 6 constituting a source of supply of fluid under pressure, which will be as sumed herein to be compressed air supplied from a suitable compressor (not shown). Although in general, circuit breakers of the type herein considered are provided with a plurality of similar pole structures, one for each phase of a poly- ,phase electric circuit, only one such pole structure or pole unit is shown in the figure and the circuit breaker will be described in detail as if it were of the single pole unit type.

The circuit breaker comprises a fixed arcing contact 1 and a cooperating movable arcing contact 8 connected in an electric circuit through terminal studs 9 and l 0. The arcing contacts are mounted to engage within an arcing chamber H which is aligned with an arc chute 12. The arcing chamber H is axially aligned with a hollow insulator is which provides a connection between reservoir 6 and arcing chamber l I through a suitable blast valve I4 for directing a blast of arc extinguishing fluid under pressure between the arcing contacts and through the arcing chamber II.

The blast valve M is actuated by a fluid motor l5 and controls a blast inlet port l8. Motor l5 comp-rises a cylinder l9, a blast valve cracking piston 20, a piston rod 2|, a spring 22, and an inlet port 24.

A solenoid operated valve 25 opens automatically if a fault current occurs on the power circuit controlled or if valve 25 is manually actuated by a push button arrangement 26. Valve 25 controls the flow of fluid under pressure from reservoir 6 through a pipe line 21, valve 25, pipe line 23, a three way valve 29, and inlet port 24 of cylinder 9 to the blast valve cracking piston 28 of fluid motor l5.

Valve 29 is connected by linkage 30 to a lever 5| mounted on a rocking shaft 3|. A linkage 32 connects rocking shaft 3| with the movable sickle shaped arcing contact 8. If arcing contact 8 is in the closed position thereof, valve 29 is in such an angular position as to admit compressed air to cylinder 19 through inlet port 24. Upon opening oi valve 25 compressed air from the reservoir 6 is admitted to a pipe line 35 which is connected to a pipe line 44 and an inlet port 36 of a fluid motor 45. Near the end of the opening stroke of the breaker the three way valve 29 is rotated approximately ninety degrees clockwise and in so doing dumps to atmosphere the air from the right side of piston 20 of fluid motor l5.

Fluid motor 45 comprises a cylinder 41, a piston 48 having a piston rod 48 movable therewith and connected through a connecting rod 50 and a lever to shaft 3|. Motor 45 is provided with a dumping valve 52 which releases pressure above piston 48 at or near the end of its upward stroke. Dumping valve 52 is biased against its valve seat 53 by a spring 54. Dumping valve 52 is provided with ports 55 which are controlled by a plate 56 biased in port closing direction by a spring 51.

Shaft 3| is provided with a cam 80 which upon rotation of shaft 3| in contact opening direction releases a lever arm 6| which in turn releases a compressed spring 62. Spring 82 acts on piston rod 2| to maintain blast valve I4 in its open position, even upon dumping of air from the high pressure side of piston 20.

Closing of the arcing contacts is initiated by energizing a solenoid operated valve 83 which is substantially identical to valve 25. Valve 83 connects reservoir 8 to a fluid motor 64.

Fluid motor 84, through the intermediary of linkage 59 causes rotation of shaft 3| to close the arcing contacts I, 8. Motor 84 comprises a cylinder 85, a piston 66, a dump valve 81, valve seat 88, spring 89, valve ports I0, inlet port 'I I, and outlet port I2.

The solenoid operated

valves

25 and 83 are substantially identical so that a description of only one valve will be set forth. Valve 25 comprises a casting forming a cylinder 80 provided with a fluid admission opening or port 8| and with an exhaust opening or port 82. Port 8| is connected to pipe line 21 and port 82 is connected to pipe line 28. Cylinder 80 is provided with a differential piston or main valve member 83 which is so arranged in cylinder 80 to provide a passage of predetermined cross section between the lower side of main valve member 83 and the upper side of member 83. Cylinder 80 is provided with a pilot valve 84, the opening of which initiates operation of the main valve member 83. Pilot valve 84 is arranged within a casting 85 which is inserted in cylinder 80. A spring 85 biases valve 84 to valve closed position. Valve 84 is provided with a throttling tip 8! which provides a definite piston area. A small amount of air through the pilot valve 84 lifts the Pilot disk or tip 81 high enough against the action of spring 88 to make the overall diameter of piston 88 efiective in lift against spring 88. Piston 88 is fitted into casting 85 so as to provide a passage of predetermined cross section for the flow of air from the lower to the upper side of the piston. Piston 88 has the upper side thereof vented to atmosphere through a plurality of vents 89. A resilient sealing material 90 is arranged within piston 88 to form a tight seal when the pilot valve 84 is closed. When the main valve member 83 is moved away from annular valve seat I so as to provide a direct passageway between ports 8| and 82 a valve member |2I connected to piston operated valve member 83 by a stem I22 closes opening I23 to prevent the escape of air to atmosphere through opening I23.

The pilot valve 84 is locked closed by a spring biased lever arm 9| which abuts against a push rod 92. Push rod 92 abuts against the pilot valve stem. Lever arm 9| is pivotally mounted at 93 and is arranged to be secured at 94 to an armature 95 Of a solenoid 98. Solenoid 98 further comprises a coil 91 and a core or casting 98 of paramagnetic material.

Spring I0| biasing lever arm 9| in valve closing direction is strong enough to hold the pilot valve closed once it is closed but is not strong enough to close the pilot valve once it is sealed open.

Casting 98 provides at the lower end thereof a cylinder I02 of nonmagnetic material which is fitted with a piston I03 of paramagnetic material. Piston I03 forming a part of a magnetic pole member I05 is biased to its lower position by spring I04 but when actuated upward moves magnetic pole member I05. Pole member I05 actuates armature upward and rotates counterclockwise lever arm 9|. Lever arm 9| then locks pilot valve 84 in closed position.

Casting 98 includes members 99 and I00 arranged one at each end of cylinder I02 providing pole surfaces III and M2 for magnetically looking the piston I03 in one of two positions.

Piston I03 of valve mechanism 25 may be actuated by the fluid under pressure in cylinder 41 of fluid motor 45 through a port I3 anda pipe line I08. Piston I83 of valve 83 may be actuated by fluid under pressure from cylinder 35 of fluid motor 84 through a pipe line I0I or from fluid under pressure in pipe line 35 through a pipe.

line I08.

A manual emergency pilot valve tripping mechanism 28 is provided for opening the main valve member 83, if so desired. Mechanism 28 comprises a pair of toggle arms H3 and 4 which are arranged to collapse in one direction only, a pair of springs H5 and H8 arranged on a pull rod Ill and balanced one against the other with the toggle arm II3 arranged in between them. i

The toggle arms 3 and 4 are manually held rigid and pivoted about an axis to actuate the lever arm 9| to release the pilot valve 84 and which collapses to return to their original position when the normal pull rod III is released. When the pull rod is actuated, spring 5 is compressed enough to overcome spring IOI, and the roller mounted on the toggle arms depresses lever 9| to allow the pressure in inlet port 8| to open the pilot valve. Spring I|5 then snaps the toggle linkage out of the way of the lever arm 9|. Release of the pull button II8 arranged on rod III causes the toggle linkage to break and ride up over the lever arm 9| and reset for subsequent trip operations.

Upon the occurrence of a fault condition on the power circuit, solenoid coil 91 of the valve 25 is energized. Armature 95 is actuated to rotate lever arm 9| clockwise about its pivot point 93 to unlock the pilot valve 84. If the fluid pressure in reservoir 6 is below a predetermined value, the leakage of air past main valve member 83, pilot valve 84 and piston 88, will not be enough to lift the pilot valve 84 appreciably from its valve seat. At a predetermined reservoir pressure the leakage of air past main valve member 83 creates a pressure between main valve member 83 and pilot valve 84 great enough to lift the tip 81 of pilot valve 84 to a point where the rate of flow around tip 81 is great enough to build up pressure under piston 88 to raise and snap the pilot valve 84 to its open position and to hold it open. The pressure between main valve member 83 and piston 88 will be reduced to a predetermined low value, thus causing the pressure on the upstream side of main valve member 83 to actuate member 83 to valve open position and to hold it open. The leakage of air past member 83 when in its open position is still great enough to hold open the pilot valve 84. force to hold the pilot valve closed, but not Spring 86 has enough enough force to close it once the pilot valve is sealed open.

The blast of air passing through casting 80 flows through pipe line 28, three way valve 29, inlet port 24 to fluid motor I5. The actuation of piston under the force of the fluid under pressure from inlet port 24 cracks the blast valve -I4 open. Compressed air is admitted through pipe line and pipe line 44 to fluid mo tor 45. Air under pressure passes through ports and actuates plate 56 downward against the bias of spring 5?. Fluid under pressure upstream of piston 48 actuates piston 48 downward causing piston rod 49 to rotate shaft 3| clockwise to separate the arcing contacts I, 8. As a result of the movement of shaft 5| and cam 05 mounted thereon spring 52 is allowed to act on the stem of piston 20 to help actuate blast valve I4 to its open position and to maintain blast valve I4 open even upon dumping tlze air from the upstream side of piston 2-0.

After piston 48 of fluid motor 45 has passed a port 13 in its contact opening movement, air under pressure passes through port I3, pipe line I05 to the under side of piston I03 arranged in cylinder I02. Piston I05 and member |05 are actu ated upward and push armature 85 upward to rotate lever arm 9| counterclockwise. Push rod 92 is slidably mounted in a cap H9 and is actuated by lever arm ill to force pilot valve 84 closed, thereby allowing pressure to build up behind main valve member 33 to close it. Once the pilot valve 84 has been closed by an external force, springs 86 and |0| are strong enough to hold it closed. I

When coil 91 is energized, piston I03 of pole member I05 is magnetically locked or sealed in one of two possible positions. If the pressure in pipe line I00 is below a predetermined value piston I03 is in its lower position and the magnetic flux passing through casting 90 passes through pole surfaces II2 and piston I03 to magnetically lock the piston I03 in its lower position. The magnetic flux in casting 90 attracts armature 95 and draws it down to pole member I05, causing lever arm 9| to rotate clockwise and spring |0I to be compressed. Clockwise rotation of lever arm 9| removes the external force from the stem of the pilot valve 84. In the event that coil 91 remains energized after the contacts 8 have separated a predetermined distance, air from

pipe lines

35 and 44 passes through fluid motor 45, port 13 in cylinder 41 into pipe line I06. Fluid under pressure in pipe line I06 forces piston I03 and magnetic pole member I05 up and away from the pole surface Ii 2. As the piston I03 reaches the upper limit of its travel the piston I03 is snapped into engagement and magnetically sealed and locked in the upper position against the pole surface I l. The piston I03 remains in its upper position against the pole surface II I as long as coil 91 remains energized with a predetermined current.

The upward travel of the pole member I05 pushes armature 05 upward and by virtue of the counterclockwise rotation of lever arm 0| forces the pilot valve 04 closed. As the pilot tip 81 begins to throttle, spring l0| forces closed the pilot valve 84 and holds it closed. Continued energization of the coil 91 holds piston I03 against the pole surfaces I II and lever arm 9| holds the pilot valve 84 closed even though the pneumatic pressure in line I06 is greatly reduced.

In the event of a flick operation of a control button which would energize coil 91 only long enough to allow the pilot valve 04 to lift and seal open, the pilot valve 84 would remain open until the valve mechanism 25 has gone through a complete operation. After the pilot valve has opened, spring I0l is not strong enough to close the valve and compressed air flowing through motor 45 and pipe I06 must raise piston I03 and pole piece I05 to rotate counterclockwise lever arm 9| to move the pilot valve 84 in valve closing direction to the point where the spring |0| takes over and completely closes the pilot valve 84 and the main valve member 83.

The circuit breaker arcing contacts are closed by energizing the coil 91 of solenoid valve 63. This valve operates in the same manner as valve 25 to allow fluid under pressure from reservoir 6 through the main valve member 83 to the fluid motor 04. The actuation of fluid motor 84 closes the arcing contacts I, 8.

Pipe lines 35 and I08 are connected to the lower side of casting 98 and actuate piston I03 of valve 03 upward to the lock pilot valve closed position during a circuit breaker opening operation. Thus, if a closing operation is initiated while the breaker is in the act of closing, the opening valve will take preference.

As shown and described the pilot valve 84 is actuated to closed position after a predetermined movement of iston 48 of fluid motor 45 or piston Hi3 of solenoid operated valve 25. Thus, the pilot valves 25 and 03 are controlled by fluid operated pistons, the positions of which are related to the positions of the arcing contacts 1, 8.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

Features disclosed but not claimed herein are claimed in an application of Julius W. Timmerman, Serial No. 264,370, filed January 2, 1952.

It is claimed and desired to secure by Letters Patent:

1. An electromagnetic means comprising in combination a core providing first and second pole surfaces, an armature, means for guiding said armature for movement in a predetermined path, means for biasing said armature in a first position extending to a predetermined point of said path, a coil energizable with a predetermined current for causing displacement of said armature along said path from said first position into a second position, a pole member locked in engagement with said first pole surface by the magnetic flux produced by said coil, said pole memher being disposed in series with said core and with said armature in the magnetic flux path of said coil, and means for moving said pole member to said point of said armature path while said coil is energized to return said armature to said first position, said moving means actuating said pole member in a direction substantially opposite to the direction of said armature displacement against the locking action of said magnetic flux at said first pole surface and bringing said pole member into engagement with said second pole surface to shift the magnetic flux path through said core and lock said pole member against said second pole surface by said magnetic flux for locking said armature in said first position.

2. An electromagnetic means comprising in combination a core providing first and second pole 7 surfaces, an armature, means for guiding said armature for movement in a predetermined path, means for biasing said armature in a first positionextending to a predetermined point of said path, a pole member engaging said first pole surface and disposed in series with said core and with said armature to form a magnetic flux path having an air gap at said point, a coil linked with said magnetic fiux path energizable with a predetermined current for causing closure of said air gap by displacement of said armature along said path of movement from said first position into a second position in engagement with said pole member and for locking said pole member in engagement with said first pole surface by the action of the magnetic flux produced by said coil to lock said armature in said second position, and means for moving said pole member and said armature together while said coil is energized to return said armature to said first position, said moving means overcoming the locking action of said magnetic fiux at said first pole surface and bringing said pole member into engagement with said second pole surface to shift the magnetic flux path through said core and lock said pole member against said second pole surface by said magnetic flux for locking said armature in said first position.

3. In combination, a pneumatic motor comprising a cylinder, a piston including paramagnetic material movable in said cylinder, a source of fluid under pressure, means for supplying fluid under a predetermined pressure from said source to said cylinder to move said piston from a first position to a second position, and electromagnetic means for locking said piston in either of said positionscomprising a core adjacent said cylinder, said core providing a first pole surface engaging said piston when said piston is in said first position, and a coil energizable with a predetermined current linked with said core for causing said piston to be attracted against said first pole surface by the action of the magnetic flux of said coil with a force less than the force exerted by said fluid on said piston to lock said piston in said first position only until said fluid is admitted into said cylinder, said core presenting a second pole surface engaging said piston when said piston reaches said second position to shift the magnetic flux path through said core and lock said piston in said second position by the action of said magnetic fiux.

4. In combination, a pneumatic motor comprising a cylinder, a piston including paramagnetic material movable in said cylinder, a source of fiuid under pressure, means for supplying fluid under a predetermined pressure from said source to said cylinder to move said piston from a first position to a second position, and electromagnetic means for locking said piston in either of said positions comprising a core adjacent said cylinder, said core providing a first pole surface engaging said piston when said piston is in said first position, an armature cooperating with said core and with said piston to form a magnetic fiux path, means for guiding said armature for a predetermined movement, means for biasing said armature in a predetermined position to form an air gap between said armature and said piston in said magnetic path, and a coil linked with said magnetic path energizable with a predetermined current for causing closure of said air ga by displacement of said armature into a second position in engagement with said piston and for causing said piston to be attracted against said first pole surface by the action of the magnetic fiux of said coil with a force less than the force exerted by said fiuid on said piston to lock said piston in said first position only until said fluid is admitted into said cylinder, said core presenting a second pole surface engaging said piston when said piston reaches said second position to shift the magnetic flux path through said core and lock said piston in said second position by the action of said magnetic flux.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,429,278 Fortescue Sept. 19, 1922 1,548,596 Ghegan Aug. 4, 1925 2,292,478 Ray Aug. 11, 1942 FOREIGN PATENTS Number Country Date 585,629 France Dec. 12, 1924 amt-r