Feb. 3, ,525,282 J. L. ENT WISTLE WIRE INSULATION TESTER. 2 Sheets-Sheet l. Filed Oct. 15, rvuertot. 1, 2a-2az/ZSZZe.

Transcription

1 Feb. 3, J. L. ENT WISTLE WIRE INSULATION TESTER Filed Oct. 15, ,525,282 2 Sheets-Sheet l rvuertot 1, 2a-2az/ZSZZe eye &ltter 11c -

2 Feb. 3, ,525,282 J. L. ENT WISTLE... WIRE INSULATION TESTER Filed Oct, 15, l92l 2 Sheets-Sheet 2 v 5 s s Sy f S ula \ YYYYYYY AAA TTT R s 1-Ue11 tot z7%zapteas Zazzazz/des Ze a 77-2, a 2 year &ltto: 1c -

3 1,525,282 UNITED STATES PATENT OFFICE. Patented Feb. 3, JAMES L. ENTWISTLE, OF CENTRAL FALLS, RHODE ISLAND. WIRE-INSULATION TESTER, Application filed October 15, Serial No. 507,860. To all whom it may concern. Referring more in detail to several Be it known that I, JAMEs L. ENTWISTLE, views, present device is adapted to be a citizen of United States of America, connected to any A. C. lighting or power residing at Central Falls, in county of mains involving a means 5 for generating 60 is Providence and State of Rhode Island, A. C. current of commercial frequency and have invented certain new and useful Im capable of furnishing a current of high provements in Wire-Insulation Testers, of amperage. The wires of main are indi which following is a specification. cated by numerals 6 and 7 and cur 65 This invention relates to certain new and rent may be taken from supply through 10 useful improvements in devices for testing a separable connector including a double insulation of insulated conductor Wires, contact plug S and receptacle 9, flow of present application being a continuation current to plug 8 being controlled in in part of my copending application for any suitable Way as by means of a double wire insulation testers, Serial Number pole switch The present device includes a portable set , The primary filed December object of 11, invention is to or unit having a casing 11 preferably of provide a wire insulation tester composed rectangular form with receptacle 9 mounted in rear wall 12 reof. Wires of parts connected and related so that 75 operation of device will be economical 13 lead from receptacle 9 to individual 20 and safe as well as efficient. fuses 14 which are preferably mounted in Anor object of invention is to gen wall 12 beneath receptacle 9 in such erally simplify and improve wire insula manner that said fuses may be changed when necessary from exterior of cas tion Still testing anor devices. 80 object of invention is to ing. A wire 15 leads from one of fuses 25 provide a portable testing unit embodying 14 to one side of a three-way electrolier a casing with electric elements carried switch 16 which is preferably of indicat and housed reby in such manner as to ing type adapted to engage contacts 17, 18 provide practical construction and in and 19 respectively connected to one side of 85 volving a minimum number of movable low current capacity indicating lamp 20, a resistance coil 21 and a second resistance 30 parts. o With above general objects in view coil 22 for connecting se various elements and ors that will appear as nature in parallel, said lamp and resistance coils of invention is better understood, all being connected at ir or sides by 90 invention consists in novel form, com means of wire 23 with one side of pri 35 bination and arrangement of parts herein mary winding or coil 24 of a low capacity after more fully described in connection step-up transformer, 25. The transformer with accompanying drawings, and in 25 is preferably of closed core type and which like characters of reference indicate its primary winding 24 is connected at its 95 corresponding parts throughout several or side by means of a wire 26 with or fuse 14 so that lamp 20 and re 40 views. In drawings, sistances 21 and 22 are in series parallel Figure 1 is a top plan view of main with primary coil 24 in primary cir portion of testing set with top of cuit. A small step-down transformer 27 is con 45 Figure casing 2 removed, is a front elevational view of nected across primary circuit with one device shown in Figure 1 with top of its windings connected with a pilot lamp of casing in place, 28 which is of low voltage and which ac Figure 3 is a rear eleyational view of cordingly has a short filament not easily device shown in Figure 1 with top of broken by oscillation which I have 50 casing in place, and found to occur in long filament high Figure 4 is a diagrammatic view partly voltage, lamps due to inductance from in perspective, partly in elevation and high tension partly in plan showing various elements The transformer 25 is provided with a magnetic leakage gap or shunt 29 and is of present device and circuits of 55 same as well as complete parts employed mounted within casing 11 beneath a in use of device. transverse support 30 upon which resist O

4 2 1,525,282 ance coils 21 and 22 are mounted, while 14. The current flows to transformer transformer 27 is preferably fixed to a side 27 and immediately causes lighting of wall of casing 11 between rear Wall lamp 28, and latter visibly indicates 12 and resistance as shown in Figure 1. that high tension terminals or binding The wires from transformer 27 lead to posts 34 are alive, whereby subjecting an outlet box 31 fixed to front wall of operator to annoying shocks is reduced to a casing 11 and carrying a socket for minimum as would occur should opera lamp 28. Also, electrolier switch 16 tor not be warned that current was on and receptacle 9 are mounted side by and he should unknowingly grasp bind 10 side in outlet boxes 46, 47, fixed to rear ing post 34 at such time. The wire 42 is wall of casing 11. fed longitudinally through testing coil The secondary winding or coil 32 of 37 in any well known or preferred manner transformer 25 is connected by means of and with voltage impressed across leads 33 with a pair of high tension bind primary circuit, a high voltage will be is ing posts 34 which are preferably fixed in induced across secondary circuit and front wall of casing 11 beneath will have same frequency as pri pilot lamp 28, and a condenser 35 is con mary frequency. As poor insulation passes nected by means of suitable wires to testing terminal 37, resistance of leads 33 so that said condenser is connected... secondary circuit is accordingly decreased 20 across secondary circuit of device, and spark jumps gap from as will be apparent erminal:37 to wire 42 being tested. At From foregoing, it will be seen t current in secondary elements 5, 6, 7, 8, and 10 are separ to condenser, of very and apart from portable part of, which causes a crater to be 25 device, and that remaining elements in poor insulation and spark thus far described are carried or housed by is exceedingly loud and bright casing 11 so as to provide a portable. ue high current, thus insuring a unit. In using present device, a sepa positive location of faulty insulation. rate testing wire 36 is employed which is Due to oscillations set up by dis 30 adapted to be connected at one end to one charging of condenser when spark of binding posts 34 and which has at occurs, high current mentioned is of a its or end a helical testing contact or high frequency and is refore safe, as coil 37 as well as a testing hook 38, coil distinguished from a low frequency current 37 and hook 38 being wired in parallel with at same voltage as would be case 35 wire leading to hook of such length as to permit engagement of hook with were condenser omitted. As resistance in secondary circuit wire being tested at a point outwardly becomes very low due to carbonizing of of coil 37 whereby bad insulation may insulator material around fault in be detected finally and quickly after 40 wire insulation being tested, current same has passed through said coil 37. The in and voltage across secondary cir hook 38 is preferably provided with a han cuit become negligible due to shunting dle 39 which is well insulated, and or of flux, induced by primary wind high tension binding post 34 is connected by ing of transformer, through mag means of a wire 40 to reel bracket 41. netic gap. This shunting of flux also 45 which carries roll of wire 42. The limits current in primary circuit so bracket 41 is provided with a suitable reel that, even upon continued short circuiting, rotatably mounted upon a shaft 43. The apparattis will not overheat and danger wire 42 is wound upon said reel and suit-. of damage to device is prevented. The ably electrically connected through shaft. magnetic gap or shunt 29 is adjusted so as to bracket 41. The free end of to limit current in primary circuit, wire 42, having insulation which is to when secondary circuit is shorted, to an be tested, is fed in any suitable manner amperage which is necessary to light through testing coil 37. As shown in indicating lamp 20 to full brilliancy and Figure 1, condenser 35 is preferably lamp 20 is of comparatively low voltage, SS located in rear of high tension wind so as to not cut down supply voltage ing or coil of transformer 25 and under at period of spark discharge. The in resistances 21 and 22 so as to provide a dicating lamp 20 is of low current capacity neat and compact arrangement of so that it will light instantly to full bril various parts, while lamp 20 is suitably liancy without lagging which is due to 60 removably mounted in a socket 44 secured heating heavy filaments used in high upon upper surface of cover 45 of current capacity lamps. A feature of casing 11.. leakage gap 29 is that same insures In operation, switch 10 is closed and drawing of a current from supply of plug 8 is inserted in receptacle 9 with no greater value than that required for bril 85 entire apparatus protected by fuses liant lighting of low current capacity 9. ( t 3

5 i 1,525,282 B lamp 20, whereby voltage impressed transformer, means to electrically con nect wire to be tested to or side across primary is reduced only by rated voltage of Said low voltage lamp, of said secondary winding, a condenser con refore reducing secondary voltage nected to opposite sides of said secondary winding, a casing in which transformer, 70 5 only maintaining a correspondingly of high small voltage amount. in This sec condenser ondary hastens carbonizing of in means and for first connecting named means is secondary carried, winding to testing terminal and to sulating material of Wire being tested, wire being tested including high tensign and also insures locating of a second binding posts projecting outwardly from fault which may enter coil 37 before one wall of casing, a tell-tale lamp above first fault leaves it. Y said high-tension binding posts, a step-down As carbonizing of insulating ma terial takes place, resistance between transformer mounted within casing and connected to said lamp, and means connect testing terminal 37 and wire 42 de 15 creases and voltage in secondary ing step-down transformer across 80 circuit drops. At this time, current in primary 2. A device for testing insulation of secondary winding of transformer 25 sets up an opposing magneto-motive insulated wires comprising a casing having a pair of high tension binding posts mount force which forces flux through ed upon exterior of one wall reof, a magnetic shunt instead of allowing same low capacity step-up transformer arranged to flow through secondary winding, and within casing and having its secondary in this way current and voltage in secondary becomes substantially negligible winding connected by a pair of leads to said to prevent overheating of secondary binding posts, a condenser connected across said leads and arranged within casing, while at same time allowing enough cur a receptacle mounted in anor wall of rent to flow in primary circuit to keep casing adapted for connection with a source During lamp brilliant. period of high current in of commercial frequency A. C. electric cur rent supply and connected to opposite sides secondary or when spark occurs, said of primary of said transformer, an indi high current does not flow in secondary cating lamp in series with primary of winding of transformer 25 but merely comparatively low rated voltage, and a mag flows in circuit of condenser and gap and ir connecting wires so that netic leakage gap for making E. e transformer have a high magnetic lea by use of condenser, a low capacit for transformer adjusted to limit E transformer may be used and yet a hig voltage, high amperage current will be current in circuit of primary wind ing to an amperage proper to light said in available for producing a loud bright spark dicating lamp to full brilliancy when and burning a crater around fault in circuit of secondary winding is shorted, insulation of wire being tested. said indicating lamp being mounted so as By use of electrollier switch 16, to be visible from exterior of casing. lamp 20 and resistances 21 and 22, vol 3. A device for testing insulation of tage may be increased across primary insulated wires comprising a casing having and secondary so that wires with different a pair of high tension binding posts mount thicknesses of insulating material may be ed upon exterior of one wall reof, a fested with substantially equal efficiency by low capacity step-up transformer arranged From present device. foregoing description, it is he within casing and having its secondary winding connected by a pair of leads to lieved that construction and operation said binding posts, a condenser connected of present invention as well as ad 50 vantages reof will be readily understood across said leads, and arranged within 115 casing, a receptacle mounted in anor wall and appreciated by those skilled in art. of casing adapted for connection with a Minor changes may be made without de parting from spirit and scope of source of commercial frequency A. C. elec tric current supply and connected to oppo invention as claimed. site sides of primary of said trans What is claimed as new is: former, an indicating lamp in series with 1. A device for testing insulation of primary, a magnetic leakage gap for insulated wires comprising a step-up trans former having a magnetic leakage gap, for making step-up transformer have a high magnetic leakage, for transformer ad making step-up transformer have a high justed to limit current in circuit of magnetic leakage, a primary circuit hav primary winding to an amperage proper ing electricity means and to be including connected to primary a source wind of to light said indicating lamp to full bril liancy when circuit of secondary ing of said transformer, a testing terminal, winding is shorted, said indicating lamp be means to electrically connect said terminal 65 to one side of secondary winding of ing mounted so as to be visible from ex- 180 H

6 O tarior of casing, a step-down trans former connected across circuit of primary winding of first named trans former, and a tell-tale lamp connected to step-down transformer and mounted in easing above said binding posts So as to be visible exteriorly of casing. 4. A device for testing insulation of insulated wires comprising a casing having a pair of high tension binding posts mount ed low upon capacity exterior step-up of transformer one wall reof, arranged a within easing and having its seconday. winding connected by a pair of leads to said binding posts, a condenser connected across said leads and arranged within casing a receptacle mounted in anor Wall of casing adapted for connection with a source of commercial frequency A. C. electric cir rent supply and connected to opposite sides of primary of said transformer, an indi cating lamp in Series with primary, a magnetic leakage gap for making step up transformer have a high magnetic leak age for transformer adjusted to limit current in circuit of primary. wind ing to an amperage proper to light said in dicating lamp to full brilliancy when cir cuit of secondary winding is shorted, said indicating lamp being mounted so as to be visible from exterior of casing, resistance coils mounted within casing and connected at one side to one side of primary winding of first named trans former in parallel with indicating lamp, and a three-way electrollier switch mounted in wall of casing beside said socket for selectively cutting out opposite sides of said resistances from primary circuit or to include same in primary cir cuit with said lamp. i5. In testing device of class de scribed, a source of supply of alternating current having a substantially fixed voltage, a step-up transformer having a magnetic leakage gap for producing a high magnetic leakage rein, a primary circuit including primary coil of said step-up transformer, means for connecting said primary circuit with source of supply, means for con necting said primary circuit to a step-down transformer, a signal in circuit with secondary coil of step-down transformer for indicating when current is flowing through primary circuit, fuse protec tion for primary circuit, means for vary ing voltage in primary circuit, said lineans including a series of resistance ele ments adapted to be connected in series par allel in said circuit, a secondary circuit including secondary coil of step up transformer, a condenser shunted across secondary circuit, means for electrically 1,525,282 connecting one side of secondary circuit with conducting portion of insulated wire to be tested, and a testing terminal connected to or side of secondary 6. In testing device of class de scribed, a source of supply of alternating current having a substantially fixed voltage, a step-up transformer having a magnetic leakage gap for producing a high magnetic leakage rein, a primary circuit including primary coil of said step-up transformer, means for connecting said primary circuit with source of supply, fuse protection for primary circuit, a signal light, a step-down transformer having its primary coil shunted across primary circuit, lineans for connecting secondary coil of step-down transformer through signal light, means for varying voltage of primary circuit, a secondary circuit including secondary coil of step-up transformer, a condenser shunted across secondary circuit, means for electrically connecting one side of secondary circuit with conducting portion of insulated wire to be tested, RF a testing terminal con nected to or side of secondary m 7. In a testing device of class de scribed, a source of supply of alternating current having a substantially fixed voltage, a step-up transformer having a magnetic leakage gap for producing a high magnetic leakage rein, a primary circuit including primary coil of said step-up trans former, means for connecting said primary circuit with source of supply, fuse pro tection for primary circuit, means for varying voltage in primary circuit including a series of resistance coils and a switch element adapted for connecting said coils in series parallel in primary circuit, a step-down transformer having its primary coil shunted across primary cir cuit, a signal element connected in series with secondary coil of step-down transformer for producing a signal when current is flowing through primary cir cuit, a secondary circuit including sec ondary coil of step-up transformer, a con denser shunted across secondary circuit, a metallic bracket for supporting a coil of wire to be tested, said coil of wire having its inner end grounded on said bracket, means for electrically connecting one side of secondary circuit, with said metallic bracket. and a pair of testing terminals con nected to or side of secondary In testimony whereof I affix my signature. JAMES L. ENT WIST.E l t