US1227844A

US1227844A - Variable-voltage transformer.

Info

Publication number: US1227844A
Application number: US3799815A
Authority: US
Inventors: Arthur Simon
Original assignee: Cutler Hammer Manufacturing Co
Current assignee: Cutler Hammer Manufacturing Co
Priority date: 1915-07-03
Filing date: 1915-07-03
Publication date: 1917-05-29
Anticipated expiration: 1934-05-29

Description

A. SIMON.

VARIABLE VOLTAGE TRANSFOBMER.

APPLICATION man 1u|.Y 3,1915.

1,227,844. Patented May 29,1917.

5E E 51 .IIIII gmail. l

AUNITED sTATEs PATENT oEEIcE.

ARTHUR SIMON, OI MILWAUKEE, WISCONSIN, ASSIGNOB TO THE CUTLEBf-HAMMEB MFG CO., OF MILWAUKEE, WISCONSIN, CORPORATION OF WISCONSIN.

VARIABLE-VOLTAGE TRANSFORMER.

Specification of Letters Patent.

Patented May 29, 1917.

Appncationnled :my a, 191s. serial No. 37,998.

n To all inkom t may concern 4 will be apparent thatntransformers embodying various features of the invention may be advantageouslyemployed in other relations.

One of the objects of the invention is to provide an inclos'ed transformer of simple, compact and durable construction.

A further object is to provide an adjustable transformer Capable of voltage regulation. between predetermined limits in very minute degrees.

The accompanying drawin' illustrates one embodiment of the invention and the same will now be described, it being understood that`the inventionA is susceptible of various modifications falling within the spirit and scope of the appended claims.

Figure 1 is a top view of the transformer with a portion thereof broken away.

Fig. 2 is a front view thereof.

Fig. 3 is a sectional view taken along the lines 3--3 of Fig. 1.

Fig. 4' is a front view of the transformer with the cover removed, and

Fig. 5-is a diagrammatic view showing the transformer connectedin a lamp circuit.

Briefly described, the transformer includes coils 1 and 2 mounted on a core 3 and provided with an adjustable armature 4, all

. of the aforesaid elements being mounted in l j side plates 11 fastened together by rivets 12 and secured by screws 13 to lugs 14 projecting upwardly from the bottom of the casing section 5. It is to be here noted that the central leg 8 of the core 3 is shorter and of smaller cross sectional area than the legs 7 and 9, functioning in a manner which will be hereinafter set forth.

The armature 4 comprises a rectangular bar of suicient length to extend across the legs 7 and 9 of the core 3 and is preferably built up' of laminations 16 confined between side plates 17 and fastened together by rivets 18. The armature 4 is slidably mounted between a shoulder 19 within casing section 6 and an elongated lug 2O projecting upwardly from the bottom of casing section 5 and is provided with an adjusting screw 21. The screw 21V as best illustrated in Fig. 1, is connected to the armature 4 by a threaded nut 22 formed by projecting the side plates 17 of the armature 4 beyond the laminations 16 vand bending the same at right angles toward each other -in an overlapping` relation.. The screw 21 passes through an opening 23 in the endv wall of casing section 6 and is secured against endwise movement by a knob 24 on the outside of said section 6 and a shoulder 25 on the inside thereof. Rotation of the knob 24 rotates the screw 21 which through its screw threaded engagement with the nut 22 produces endwise adjustmenty of the armature 4 for a purpose which will be hereinafter set forth. In practice there is considerable tendency' for the armature 4 to vibrate and in order `to prevent i undue vibration the same is provided with a leaf spring 26 having reflexed ends 26 adapted to bear against the side wall of casing member 6 and resiliently hold the armature 4 in engagement withthe oo re 3. A

Before proceeding further the function and operation of the transformer will be described in connection with Fig. 5. As before stated the transformer is particularly adapted for use with projecting arc lamps and in Fig. 5 a lamp is diagrammatically illustrated as provided with carbons 27 and 28 connected by conductors 29 and 30 to the terminals of the coil 2. The coil 1 is Vconnected across the linesL and L and functions as the primary coil of the transformer to generate lines` of force which passing through the coil 2; or secondary coll of the transformer, excites the latter. However, due to the Efshaped construction of the core -j 3 two magnetic circ-uits are provided, for the lines of force generated by the primary coil 1, one extending through the leg 9 and the other in shunt thereto through the leg 8. It will be understood by those skilled in the art that if the magnetic reluctance of the circuit passing through the leg 9 is varied the ratio between the number of lines of force passing through this leg and those passing in shunt thereto through the leg 8, will vary and produce a variation in the 1nduced voltage of the coil 2. The reluctance of the magnetic circuit passing through the leg 9 is varied by the armature 4. which -is adjusted endwise to vary the contact surface between the same and the end of the leg 9.v An increase in contact area between these parts willefect a decrease in the magnetic reluctance of the circuit therethrough and a decrease in contact area will increase` the reluctance thereof. It is therefore obvious that movement of the armature 4 toward its extreme right hand position as shown in full lines in Fig. 5 increases the number of lines of force passing through the leg 9 thereby effecting an increase in the inv duced voltage of the coil 2 while movement towar the left hand position as shown in dotted lines Aproduces. an opposite effect.

It is to be here noted that the voltage limits between which the transformer isA adapted for regulation is'ldetermined by the relative vle .reluctances of the magnetic circuits passing through the legs 8 and 9. In the transformer illustrated .it is desired when the armature 4 is.in its extreme right hand position, `that the reluctance of the magnetic circuit passing through the leg 8 be high in comparison to that of the circuit passing through the leg 9. The magnetic reluctance of the circuit passing through the-leg 8 is made relatively high by making it shorter than the legs 7 and'9, to provide an air .gap between the same and armature 4v and also by making the cross sectional area thereof relatively small in comparison to .9. Here it should be noted that by slightly adjusting the armature 4 endwise the secondary voltage can ble regulated in very minute degrees and that the screw 21, due to its threaded engagement with the armature 4 enables a very line adjustmentv thereof.

Again referring to the mechanical struc` ture it will be observed from Figs. 1 and 2 that the casing sections '5 and 6 each comprise a rectangular box-like member having'j Ventilating openings 31 therein. The

casing sections

5 and 6 are secured together by screws 32 passing through the front wall of the casing .section 6 andengaging tapped lugs 33 f von the inside of the casing Y casing section, 5 is provided on opposi e section 5. T e

ends with openings containin insulating bushings 34 for the reception o conductors and is also provided with a projection 35 for' limiting adjustment of the armature 4 toward the left.

It will of course be understood that the 7 specific transformer above described is to be considered merely as illustrative of the present invention and that the same is susceptible of various modifications falling Within the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is l. In a variable voltage transformer, in

combination, a primary coil, a secondary,8

coil, an E-shaped core therefor, said Lcoils being separately mounted on two legs of said core, the third leg of said core providing a magnetic shunt for said primary coil and an armature bridging all of said A legs, said armature being adjustable to in.- crease and decrease the reluctance of the magnetic circuit passing through the leg of said secondarycoil to respectively decrease and increase the induced yvoltage of said secondary coil. y

2. In a variable voltage transformer, in combination, a primary coil, a secondary coil, an E-shaped core therefor, vsaid coils being .separately mountedon the end legs of core, the middle leg of said core providing a magnetic shunt for said primary coil and an armature bridg'in all of said legs, said armature being adjustable to increase and decrease the reluctance of I the magnetic circuit passing throughl the leg Aof said secondary coil to' respectively decrease and increase the induced voltage of said secondary coil.

-3. In a variable voltage transformer, in

combination, a primary coil, a secondary coil, an E-shaped core therefor, said coils being separately mounted on .two legs ofv said core and the third leg of said.v core providing a magnetic shunt for said pri-110' mary coil and being of relatively higher reluctance than the leg of said secondary coil and an armatue bridging all of'said legs, said armature being adjustable to increase and decrease the reluctancevof the 1(15 magnetic circuit passing through the leg of said secondary coil to respectively decrease and-'increase the induced voltage o said secondary coil.

-4. I n a `variable voltage transformer, .in

combination, a primary coil, a secondary coil, an E-shaped core therefor, said coils 1 being separatelmounted on the end-legs of said core, te middle leg of said core 'providin marycoll and bein of relatively hi 'her reluctance than the eg of said 'secon ary coil andan armature common to the three legs of said'core, said armature being 1011-V gitudinally adjustable "to increase and de- 1'30 a magnetic shuntfor said pri- 125 I crease the reluctance of the magnetic circrease the induced voltage of said second-` ary coil.

5. In avariable voltage transfoii'mer, in combination, a primary coil, a secondary coil a substantially E-shaped core therefor, said coils being mounted on two legs of said core and the third leg `being of restricted cross sectional area and length relative to said former legs and a longitudinally adjustable armature common to said legs.

In a variablevoltagc transformer, the combination with a two-part inclosing casing, of an E-shaped core carried within one part of said casing, coils carried by said core, an adjustable armature associated with said core, said armature being slidably supported on opposite sides between the parts of said casing and means operable from the outside of said casing for adjusting said armature.

7. In a variable voltage transformer, the combination with a two-part inclosing casing, of a laminated core mounted within 'said casing, coils carried by said core, an

adjustable armature associated with said core, said armature being slidably supported on opposite sides between the two parts of said casing, and means operable from the outside of said casing for adjusting said armature.-

8. In a variable voltage transformer, the combination with an inclosing casing comprising two relativelyl inverted box-like sections, of a core mounted within said casing tions, of an E-shaped core carried within,v

said casing and secured to one of the sections thereof, a coil mounted on each of the end legs of said core, an armature cooperating with the end legs of said core and adjustable relatively thereto, said armature being slidably mounted between projecting portions on each of the sections of said casing and a screw operable from the outside of said casing for adjusting said armature.

l0. In a variable voltage transformer, the combination with an inclosing casing comprising two relatively inverted `box-like sections, of a laminated E-shaped core mounted within said casing and secured to one of the sections thereof, a coil carried on each of the end legs of said core, a laminated armature bridging the extremities of the end legs of said core, said armature being slidably supported between projecting portions on each of the sections of said casing and a screw operable from the outside of said casing for longitudinally adjusting said armature.

11. In a variable voltage transformer, the combination with an inclosing casingcomprising two rectangular relatively inverted box-like sections provided with a plurality of ventilating openings, a fiat E-shaped laminated core mounted within said casing and secured to one of the sections thereof,

a coil carried on each of the end legs of said core, a laminated armature bridging the extremities of the end legs of said core, said member being slidably supported between projecting portions on each of the sections of said casing, a rotatable screw having an operating knob on the outside of said casing for longitudinally adjusting said armature and resilient means secured to said z armature and interposed between the same and the inside wall of said casing for yieldingly holding said armature in engagement with said core.

In witness whereof, I have hereunto subscribed my name.

ARTHUR SIMON.