US1521145A - Overload-indicating apparatus for transformers - Google Patents

Description

Dec, 30.- 1924 v T. D. ADAIR, JR OVER'LAD INDICATINQ APPARATUS-.FOR TRANSFO RMERS gr. ww.

Patented Der, Eil, i924.

narran stares ears THOMAS DONALD ADA1R,`JR., OF DORCHESTER, MASSACHUSETTS, ASSIGNiOR, BY

MESNE ASSTGNMENTS, TO LEONARD L.

ELDER', `GF BRQOKLTNE, MASSACHUSETTS,

" .AND DAVIS S. BOYDEN, 0F BOSTON, MASSACHUSETTS.

DVERLOAD-TNDICATING ATDPARATUS FOR TRANSFQRMERS.

Application filed August 15, 1922. Serial No. 582,057.

inent-s in @verload-nclicating Apparatus for Transformers; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it 'appertains to make and use the same.

The present invention relates to an improvement in overload indicating apparatus for transformers, and more particularly to semaphores for use in connection'with such apparatus.

In the transformer disclosed in the application iiled by T. Donald Adair, J r., April 8, 1921, Serial No.4 459,574, the semaphore was enclosed within a semaphore box having a window in one side. With suchconstruction whenl the semaphore drops it is exhibited at the window. ln practice, in order to render the semaphore visible and distinguishable, it is painted white. Upon the occurrence of transformer overload the white Lseniaphore'was exposed to view by the dropping behindA the window. The box, however, was made of metal and the inside was illuminated only by such light as could enter through the window, asia consequence jef which there was a mirror effect observed. The glass in cert-ain positions ofthe sun or clouds would reflect light to such an extent that the observer at a distance, as was necessary because the transformers are usually mounted on poles, would be unable to distinguish the lightr reflected from the glass from the white semaphore. Y

lt was attempted to overcome this objection by the construction disclosed in Vthe applicationl of T. `Donald Adair, Jr., filed October ll, 1921, Serial No. 507,029, byproviding the box with two windows, one at cach side, so that transmitted light might be availed of, that is to say,`ligh t passing clear through the box, to Vindicate the fallling of the semaphore when it stood against a light background, and at the sametime it was provided that a white Vscreen covering part of the area between'thevtwo windows should be exposed by the dropping of the semaphore for the purpose Vof rendering the signal visible-against a darli background. But the box in this case, as in the former, was made of metal and excluded v.light more or less, and consequently7 in this box, as'in the former, the mirror effect was still encountered, and under some condi.- tions it interfered with the visibility of the signal.

The value of these semaphores is considerable even if the visibility of the signal Y is low, but with a high visibility the value of the signal ismuch enchanced. To this end the present invention contemplates the production of a signal of high visibility, and consists in the semaphore hereinafter described and particularly defined in the claims.

In the accompanying` drawings illustrating the preferred form of the invention, Fig. l is a vertical sectional elevation of the construction ofthe invention; Fio. 2 is a transverse sectional elevation; anc Fig. 3 is a plan.

The illustrated embodiment of theinvention is described as follows: The overload indicating apparatus for transformers comprises a semaphore 19 operated by mechanism responsive to the overload conditions of the transformer coils, comprising a heat responsive element, such as a coil or spiral like that described in said applications, or of any suitable form, which is connected to a rotatable spindle 25 journaled at its upper end in a cross bar 27 within thesemaphore box 28, mounted on the upper end of a depending boss 29, having a threaded portion 30 adapted to be screwed into a hole in the cover of the transformer. Variations in the temperature of the coils in tlv,` transformer operate through the expansion or contraction of the heat responsive coil or spiral to cause rotation of the rotatable spindle 25. The semaphore box is made of one piece of glass. It is provided with bail groove projections 3l von its top which receive the horizontal portion of the `bail 32 which has two arms extending downward at the sides of the box which enter two slots 33 in the base plate 34 and receive on their ends the lmurled nuts 35. A rubber washer 36 is interposed between the base plate 34C and the lower edge of the boX 428. .By screwing upthe nuts jon 4the bail the box is clamped tightly against the base plate, and the entrance of water or air throughrsuch opening is prevented. yThe :semaphore 19 is suplrbortedjto slideon veri rotated to bring the notch under thepspring,

as in the construction ofI said applications. rlfhisspring 4lis permitted to all'by two steps, beingl provided with a shoulderl43 which, when'the semaphore is irst: permitted Y .to fall, catches 'on the disk 42 and holds thesemaphore in a position vhalffwaybetweenm its t'p,4 and bottom positions. This :construction is4 like that illustrated in the Davis S. Bot'vden'afplication tiled June 16,*V

. Y 1921, Serial No. 47 8,205.

l The semaphore `is provided witha re-set- Lting device consisting ont, a level-'44"pivoted at `45, adapted to be engaged on itsnnder side by the refsettingpin 46. The 1re-setting pin projects through the bottom ofthe -base of the, device and is covered byua 'cap 4 7 which has a hole extending downward in its center for a, distance to receive thelo-wer l lend ot'theLre-setting pin and which has a screw-threaded. shankl adapted to bereceived lin ascrewthreaded Vhole m the ibase, through. which the re-setting pin, much smaller ,in size, projects. A rubber washer the closure to be made tight. By means of the vwasher under the box and the washer .underl the resettingjpin cap the 'apparatus is made hermetically tight, and this prevents the entrance and 'egress'of airand of moisture,.an'd maintains the condition ollthe ap- .paratus tree from exposure to the mfiuenco o'litheweather and insects.

The upper'ends of the two rods 40 ,are receivedin two holes in the topV piece49 of a background 'against which' this device may? Eiframe, which asl seen in 2,`"co1i'sists ot' a j flat base 27 and two vertical supports 50 (see Fig. 1,),fupon the -upper ends of which the horizontal top piece 49 is formed. This fralnejis secured to-the two postsV 5l and 52 (fof which thepost 5l carries the resetting lever) which are formed on the base plate f vIrre'spective of the vsurroundings or the beviewed,` the full light which is enabld to illuminate the whole apparatus by reason of the box being made of glass, ,substantially completely obviates anyimirror liect on the glass.V yWhen 1t 1s viewed .against a darkV background the semaphore cuts otthat dark bacllground.` W Then viewed against a light background, the i a dark'object again'stit. The Kresultfis that the SemapbereisClient.high Visibility by reason of the employment ot' aglass vbox:

,or ,c,over. .The ideal condition Would, ot'V course, be that in which no Ycover at all was employed, but such cond1t1on,1sas.n matter ot`l practice, impossible because weather Vcmdition's and the, liabilitypof injiiry byianimais. such asbirds, vsquirrels `andfinsects would Vbe present, so fthat ,thejprsent coni. structionoffers .anY approximationto such ideal conditions.which,.secures a high de- `greener visibility-'lof thesemaphore,V

The use of thebail construction fnhold'ing the box on the baserplateisfof greatlconvjenf ience .in theuse'of the .device.becausefitienables the inspector to remove thecoverentirely .andto have'full and `tree ,accessft'o the apparatus for thepfurpose ocleaning itJsjfor removing any rust,fdust,.fcorr0sion o r other e f'presents impediments. to.. its goocl-f.0pe1-ation,and Y quickly to restore it to itsl originalti'ghtconydition'attach cleaning operation.,1

V-The feature of ^he initicallyl-,sealing the box is one [which contributes greatly to 'the life and durability ofithe instrument be-V cause itgprevents the` corrosion and ,deterio- Vration incident tothe ohangefof the Vair Y oontent of the 'box due tothe expansion and contraction such air resulting j from changes of temperature, A

:n will .befobseifved that itis, essntialjthat Vthe front vandback walls of thecasingjwshall .be tramsparenty and Athatfthe semaphoreplate `l9 shall nothonly be substantiallyfopaque ,but` shall have substantial width, so that 48interposed` between'. the head of the cap x .4 7 and the bottom of thebase plate enables whenitfis in itsfjup' posit-ion Ywill, so to Speak, block ol-ajrlarge part ofthe 'top anel Ot' vthe, casing, g1 eavingtheflower haia or panel substantially transparent tonenable the light rays tofpassclearthrough the 'cas ing. lVhen theopaque semaphore-plate is down, thenthe conditions are reversed, the

yligljit `passing 'clear through the'top zone or panel of the casing,u l ,Ijn':thiswvayjthe'panel blocked ofi; bythev opaqueplate will, by comf p arison with the "transparent 7'sectimI oaf` the basing, be, readily observable Iat consideru indicating apparatus V 'for transformers havingf in"A combination, a

semaphore, a heat sensitive elemengjconnections between' the semaphfle.` and` the 'heat Y sensitive Y element 'perm ittingrV thelsemaphore tto' `drop",upon theindication' et, ritic'al; tem perature by the heat sensitive eleV Vent', a box Yl'or covering the semaphore, a Wire bail extending over the box, and means for securing it to the base plate to hold the box in place thereon.

2. Overload indicating` apparatus :for transformers comprising a heat sensitive element, a semaphore, connections between the heat sensitive element and the semaphore acting to drop the semaphore upon the attainment of a critical temperature at the heat sensitive element, .a base plate for supporting the semaphore, a box for covering the semaphore, means for packing the joint between the box and the base plate, a re-setting device having a portion extending through the base plate, and a cap for coverino' the rea-setting device, said box and ap hermetically closing access to the box.

3. An overload indicating apparatus for transformers having, in combination, a box for enclosing the indicating apparatus, the Walls of this box being transparent, said indicating apparatus embodying a light-obstructing semaphore-plate of substantial Width adapted to be held in the upper part of the casing or in the lower part thereof, so that in either position it Will render the casing nontransparentl at that point and thus indicate at a glance under all light conditions Whether the semaphore-plate be up or down.

T. DONALD ADAIR, JR.

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