US1166699A - Alternating-current magnet. - Google Patents

Description

w. D. L'UTZ.

AL-TERNATING CURRENT MAGNET.

APPUCATION FILED JULY 31.19l3.

1,166,699, Patented Jan. 4-, 195 5.

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WITNESSES: max m/a v 7 b2 WX/TLZ h f {#5 2 Z I" l 05/, ATTO NEW lLl'lhlTTED STATES PATENT OFFICE.

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I), LUTZ, OF ALLENLDALE, NEW JERSEY, ASSIGNOR TO OTIS ELEVATOR .fel fi, OF JERSEY CITY, NEW JERSEY, A. CORPORATION OF- NEW JERSEY.

ALTERNATING-CURBENT MAGNET.

Specification of Letters Patent.

Patented Jan. 4, 1916.

ication filed. March 550, 1812, Serial No. 685,112. Divided and this application filed July 31,

1913. Serial No. 782,164. Y

. cnt magnets, and although i ted for general use, it is more adapted for use in conjunction aperatus such as is used in a electric elevators.

t is a division of my coication for a patent on alterbrake magnets, Serial No. d March 20, 3.912.

objects of my invention is to lo and cheap alternating current o lot which is of highly efiicie t constru and which involves a minimum amount ()1 machine work.

Another object of my invention is to provide a simple id practical means for keeping the parts lubricated in a manner whereby all wear and. noise is practically eliminoted ml the heat generated therein greatly reducer.

Other objects will appear hereinafter, the novel combinations or elements being pointod out in the appended claims,

ting to the drawings, Figure 1 is a view of the magnet and other 2 is a detail sectional view of upper part of the nnwnet showing an improved m l-hcd. of guiding and lubricat iug" net core, 3 is a view in part modified form'of magnet.

' cc characters denote similar provide or pot 1, contains an electroinn .v 3* connected to the mechanism to erated, as for example a brake lever "not comprises a field member built up o la)" nto as is usual in the construction alternating current magnets, the assembled laminae to ig held in posi- 6y of end plates i and bolts, 3 and, 6. This field member is i1l'\i in p tion inside of the pot I rods 7 which pass through as i and can in bosses cast in I lamina are stamped out of sheet iron and in form are substantially rectangular with a pole piece 9 extending upwardly'at the lower end and an opening at the upper end to receive a core 10. The core is also of laminated construction, comprising a number of stampings 10 having stays or end plates 11 preferably made of bronze; the laminae and end plates 11, together with a core head 12 being fastened together by suitable rivets 13. The head, 12 and the upper part of the core are surrounded by a'divided casing 14: formed by an extension of the field end plates 4: and the space therebetween is filled with Babbitt metal 15, which is poured in in a molten state. The lower end of the core may be tipped with some non-magnetic maform a single solenoid in efiect. The wind ing is wound on spools which are held in place in. thefield frame by means of the;

field pole 9, and the top and bottom sup ports 18 and 19, respectively, one or more wedges such as designated by the numeral 20 being driven in between the upper support 18 andthe top magnet spool, after the magnet spools have been assembled, and held in place by means of a set screw as shown. The core head 121s hollow and contains a bearing, to which is pivoted by means of a pin 21, a connecting link 22 provided with a flange 23 The'upper end oi. this link is in, this instance pivoted by a pin 24 to the brake lever T he upper end of the pot 1 is provided with a cover 25 which loosely fits the core liea' 12 and holds in place a felt washer 26 which is in con tact with the head and which serves the purpose of a stulling box therefor, excluding all dust and dirt from the interior of the mag-- net. casing or pot. The pot is partially filled with transformer oil which has free access to all parts of the magnet and its function is to keep all'parts thoroughly lubricated and to act as a cushion for the'solenoid core, while at the same time the oil acts as heat conveying medium for carrying the heat generated in the magnet to the pot where an incense it is radiated. As an additional means for insuring that all parts of the core may be supplied with lubricating oil, I sometimes provide a channel. in the Babbitt metal surrounding the core (see Fig. 2), which contains a wick 27, one end of which dips into the oil contained in the pot, while the other end is in contact with the core.

The pot cover 25 carries a stiff coil spring 28, which is somewhat shorter in length than the distance between the cover and the flange 23 upon the connecting link 22. This spring serves the purpose of overcoming the residual magnetism of the core and magnet fieldafter the magnet winding is deenergized. The conductors 29 lead to the terminals of the magnet winding and are incased in a conduit 30 secured capped on one end, is connected to the lower end of the pot and furnishes a convenient means for filling and emptying the pot with oil whenever necessary.

In the modification shown in Fig. 3, a circumferential groove '32is turned to receive a flange on the divided casing 38,. and the cover 25, flange and ,pot, are held together by means of tl'irough bolts threaded into the pot; These bolts are not shown in the sectional view Fig. 3, since their presence would tend to confuse the drawing. This construction dispenses with the rods 7 of Fig. l, and in some respects is preferable thereover. The flange 82 divides the pot into two sections which are in communication with each other through the adjustable puppet valve 3%. This valve is independently adjustable in both directions and is so arranged that it Will never close tightly but will merely restrict the flow of oil from the lower section t5) the upper section when the core is drawnklownwardly, and will control the flow of the oil in an opposite direction. This action tends to cushion and re tard the release of by the magnet core, such as the Wake, but permits of a rapid application thereof.

By the use of Babbittmetal for guiding the magnet core,

work. The amount of clearance or air gap 35 (see Fig. 2) between the lateral faces of the magnet core and the magnet field, may be very slight indeed, thereby improving the efficiency of the magnet, and, when alternatingcurrent is used to excite the magnet, cut down the current consumption. The Babbitt metal forms a very efficient wearing surface for the core, and since ampleprovision is made for keeping the parts lubricated, all wear of the magnet parts is practically eliminated. It will be observed that the oil contained in the magnet casing or pot 1, not only acts as a lubricating agent, but also as a means for dampening the vibrations set to the pot. A. riser 31,

the mechanism operated I provide a simple, cheap I and highly eiiiclent constructlon involving a minimum amount of expensive machine up in the magnetic parts when the same are energized by an alternating current. The oil has free access to all parts of the magnet and forms a film over the lateral faces and lower end of the core, which prevents an actual contact of metal to metal. In alternatingcurrent magnets, the flux constantly varies, and when said current is of single phase the magnetism is reversed with each alternation of current. That is to say, for each alternation of current, the magnet is. dead and there is no pull upon the core. Now, since the spring 28 is tending to pull the core in an upward direction at all times when the circuit of the magnet is closed, it follows that the core will tend to move away from the field pole 9, while the flux passes through zero, only to be pulled back in con tact again when the flux rises in value. ()rdinarily this action sets up a violent hammering effect which not only tends to batter the end of the core out of shape and to make the action of the magnet extremely noisy, but also to reduce the elfective pull of the magnet.

The tendency of the residual magnetism to cause sticking of the magnet core after the exciting current has been cut 0d, is practically overcome by means of the air gap or break in the magnetic circuit found at the bdttom of the core and at the lateral faces oil the core where it passes through the field at the point 35, and this tendency'is reduced by this construction to such an amount that if desired the German silver spacer 16 upon the lower end of the core may be removed without preventing the metallic contacting.

While I have described my invention in conjunction with a single phase alternating current, the same may-be used to equal advantage with polyphase or other currents of any nature.

Without limiting myself to the precise construction and arrangement of parts herein described and illustrated,whfat I claim and desire to have protected by lletters Patent of the United, States is zl. The combination with an electro-responsive device, of a movable core, a guide for said core, and means for supplying oil to both ends of said guide.

2. In an electro-responsive device, the combination with a solenoid magnet, of a movable magnet core, a casing containing fluid surrounding said magnet and core, apartition dividing said easing into two parts, and a valve in said partition for regulating the passage of fluid displaced by said magnet core.

3. In an electro responsive device, the combination with a solenoid magnet, of a movable magnet core, a. casing containing fluid surrounding said magnet and ,core,. .a

parts from actually danger of the core sticking, the oil iOS partition divic'iing said easing into two parts,

a valve in said partition for regulating the passage of fluid displaced by the magnet core, and means for limiting the movement 01 said valve toward closed position.

4 In an electr0-respensive device, the combination With a solenoid magnet of a. movable magnet core, a casing containing fluid surrounding said magnet and core, a horizontal partition dividing said easing into two parts, a, valve in said partition for regulating the passage of fluid displaced by the magnet core; and means for limiting the movement of said valve toward closed position. 3i 1 5 In testimeny whereof, I have signed my name to this specification in the presence of two subscribing Witnesses.

WILLIAM D..-LUTZ. Witnesses WALTER C. STRANG, ERNEST L. GALE, J r.,

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