US2537384A - Electrical surge recorder - Google Patents

Description

Jan. 9, 1951 Filed Jan. l5,

P05/Tl VE F/GURE J. H. WAGHORNE ELECTRICAL SURGE RECORDER 2 Sheets-Sheet l Jan. 9, 1951 J. H. wAGHoRNE 2,537,384

ELECTRICAL SURGE RECORDER Filed Jan. 15, 1948 2 Sheets-Sheet 2 o 5 l0 l5 zo 25 3o 35 40 SUI-mg penn 1N H/Lovours am Patented Jan. 9, 1951 UNITED STATES PATENT OFFICE ELECTRICAL SURGE RECORDER John Henry Waghorne, Toronto, Ontario, Canada Application January 15, 1948, Serial No. 2,484 In Canada June 10, 1947 -the electrostatic photo-sensitive type, in which a record of the characteristics vof a surge is obtained through the instrumentality of aconduct- Ying electrode in engagement with a photo-sensitive surface, thereby producing so-calledLichtenbergA figures.

It is a main object of this invention to provide a device of this character having a light-proof` and weather-proof casing for containing the sheet of sensitized material on which the surge is to be recorded, the casing being so constructed that it may be readily dismantled to permit the lm of4 sensitized material to be replaced.

It is another object of this invention to` provide a surge recorder which may be coupled to high voltage lines or other electrical devices by connecting it on the line-side ofthe capacitance voltage divider.

, mechanically movable element, having appreciable inertia, may be made to sensibly record. y Such a, surge may be caused in electrical circuits by... various agencies, such as lightning, grounds of exceedingly short duration and other causes,

and may adversely affect the operation of the circuit in accordance with the steepness, duration, amplitude and polarity thereof. It is therefore highly desirable that observation of these characteristics be obtained from an instrument that shall be easy to operate and that shall other- .wise be adapted as a standard electrical instrughment.

1 1@Apparatus of this nature for recording electrical: surges was iirst disclosed in an article entitled ..The- Klydonograph by J. F. Peters which ap- ,peared in Electrical Worldon April 10th, 1924.

graphic development. The pattern has a characteristic design if the voltage is positive, and a `different characteristic design if .the voltage is negative. The diameter of the pattern is a funci 5 tion of the peak value of the voltage applied and hence, through proper calibrati-on, the pattern can be used to measure the value of an applied voltage. Y

- For a more complete description of the operat- Y Ving principles of `such devices, reference is made to the aforesaid article by J. F. Peters and also to U. S. Patent No. 1,649,180 dated November th, 1927. Several improvements have since been made in this method of surge recording, including `15 the recording of botha positive and negative fig- Y Yure regardless of the actual surge 'polarity by us- 'ing'za double film unit, as disclosed in U. S. Patent .No. 1,702,412 dated 4February 19th, 1929. l

There have similarly been many methods of coupling surgeprecorders to high voltage lines and other electrical devices in order to supply n reduced voltage to the recording units. Various 'arrangements of rings, bars and insulator strings have been used to provide the capacitances to produce a voltage divider. However, they have all been large more or less permanent installations which are relatively expensive, and these frequently couple in some degree to other phases or circuits as well as to the one desired.

All of the foregoing and still further objects and advantages of the invention will become apparent from a study of the following specification, taken in conjunction with the accompanying drawings, wherein like characters of reference designate corresponding parts throughout' 'the several views, and wherein:

Figure l is a view partly in elevation and partly in vertical cross-section of a completely assem- .bled surge recorder constructed in accordance 40 with. this invention and shown connected to a .power line,

'Figure 2 .is a perspective view of the said surge recorder,

Figure 3 is an exploded perspective view of the recording unit, y

Figure .4. is achart illustrating the directcalibration of atypicaLrecording unit constructed K 'with the rods 3l and 4.

tween the peripheriesfoi the dishes.,

Figure 5 is a chart illustrating the calibration of the combined recording and coupling units with sensitivity control extensions of three dfferent lengths, and

Figure 6 is a chart illustrating the potential distribution between a conductor and ground plane.

Referring particularly to Figures l and 3, the recording unit comprises two' concave dishes. I and 2 made of electrically non-conducting material disposed with their peripheries abutting one, another to provide a hollow shell. said dishes extend threaded rods 31'and- 4' respectively, the said rods being secured to the respective dishes by oopoitely facing pairs of locking nuts 5 and 6.

Through the I carrying the surge.

4 Thus resistor 29 may be connected between hood 2i! and rod 4.

` Remarks vlneutral plane is established through the center of the unit. Thus, the recording is similar to Films of electrically conducting paint 'I and B are painted on a portionofithe..

inside surfaces of dishes I and 2 respectivelyso, as to be electrically insulated from one another,

and these are respectively in electrical contact The inner end ofy each rod is hollowed4 out, and

Vinsertedtherein are spring-pressed pins 9 and t0; Coiled around the. rod-s are( hel-ical springs l l .and f2 respectively,l one end of the said springs y' of the rod in which'i't is inserted. The` spring is vtherefore in tension when it is attempted to force the, pin inside, its rod, and` therefore each assembly of rod, pin and tension spring provides. a .spring-pressed electrode.

The hollow shell provided bythe two concave dishes, with, theirperipheri'es abutting one `another is. divided by a` flat partition of. electrically non-conducting. material,` [31 which is gripped' besensitized films 1.4 and lare disposed on opposite faces of t0 are in intimate contact therewith.. If desired, the nlm may be in sheets cut ton dimensions. such that portions thereof` may be gripped between the peripheries of the dishes. A'rubber v'band .i67 securely closes the assembly and makes it light-proof and weatherproof- The coupling unit` comprisesy an aluminum hood 20 through the center of which extends a bushing 2| provided with internal. threads 22; An

,aluminumhinged hanger 23 is. secured to the hood by means of the bushing 2| extending; therethrough the nut 24. which is screwed on the .said bushing. At thel opposite end of the hanger a hoolr 2.5 provided with a screw clamp 26 whereby the device.. may be secured to a power line 21 or other power device wherein. the surge Ais toy be. measured.

An extension 28 issecured to the'outer: end. of

.frod 4L,- The length of the extension 28 which s used is determined by the operating voltage of fthe: equipment;- undery test; with differentlengths of extensions diierent voltage ranges maybe re.'-

cordect It is'usualto choose an. extensionof a length such that it will record voltagesgreater than twice the', normal line voltage, as. surgesv below this value are not of interest'. Y With high operating voltages a dark; spot may under somey conditions beproduced on the sensi:-

Vtizedlrns4 even'4 when no .surges have occurred.

. `40 theV partition, and the spring-pressed pins 9 and when it is mounted closely to the line.

that inv a unit with a ground plane, except that twiceA the voltage.. is required to produce the same sized' figures.' 1n Figure 4 is shown a direct calibration of a typical recording unit constructed in accordance with this invention, for both posiytive .and negative Lichtenberg figures using a 11/2 x 40 microsecond weave. To obtain this cali- .brat/fion, voltage surgesfof various known magnitudes. are applied-J' between the "terminals of the recording unit (therecording unit oi course hav- 'ing tobe reloaded with fresh sensitized'iilrn'after i each voltage surge), andafter the films are developed'the radii of the'patterns produced are plottedagainstthe known applied voltages, as shown in Fig. 4.' n i l Heretoforefsurge recorders have been' coupled to high voltage 'lines and other electrical devices with the recording unity at the grounded end; this has required 4a small'electrostatic capacitance irom the unit to the line compared to the capaci- 'tance from the lijve terminal of the unit to ground ror neutral plane. In accordance with this invention, the unit is coupled' on the line side of` the capacitance divider therebyreversing this condition of operation.'v This makes the recorder practically independent of location with respect to other circuits and" to ground because the'. volt'- age distributionin the neighbourhood' of acon- `ductor is relatively independent of the location of the ground planefor grounded objectsv when the spaoing'be'tween the two is greater than about 5feet. For a conductor of radius' 0.04 feetv ('one inch difameterlnthe voltage distribution isfsho'wn in Figure 6', for values of conductor height of`5 feet land 20 feet above the reference plane. It will be seen from these curves that wide variations in the height of the; conductor above the reference plane -will'have negligible effect upon the voltage adjacent the conductor, provided the conductor is at a height greater than 5 feet vfrom ground. vThe hood '20 will 'not materiallyv affect the voltage distribution as given in these curves (Figure 6) 4 The hood is not intended'to be nor is it a corona shield; it

is an electrostatic shield, whose function is to control andreduce the effectiveelectrical distance of rod ll' from the line, thereby allowingy use makes the recording practically independent of variations in proximity of vother lines" ror of y'grounded objects.

Figure 5 shows the calibrations for thefrecording and coupling unitscoinbined, using three different-sizes;v of sensitivity-control extension 28.

A 1% x40` microsecond wave was used for these .calibrationsA Itwill bev noted that the concave downward curvature seen in these curves is not present in the calibration curve of the. recording vunitperse shown in Figure 4; this cannot be dentely. accounted,or, Vbut; ionization., around f I It is thought the edge' of the hood at the' higher voltages "may be' a possible explanation of this variation.'

. The surge recorder disclosed -herein may be in- Ystalled'andfremoved from the live highvoltage linesor'electrical devices by means of atreated 1 l.wooden stick having a head designed to engage clamp`26.

that the construction anduse of the invention will be apparent from the above description of the various parts and their purpose. It is to be understood that the form of my invention herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of my invention or the scope of the subjoined claims.

What I claim as my invention is:

l. A surge recorder of the electrostatic photosensitive type for electrical apparatus, comprising a hollow non-conducting member having spaced walls disposed opposite to each other, an electrically non-conducting partition therebetween, a lm of sensitized material on one side of the partition, a rod-type electrode secured to one of the said walls and having one end in contact with the film, another rod-type electrode secured to the other wall in substantial alignment with the rst mentioned electrode and having one end adjacent to the other side of the partition, the other end of one of the said electrodes being adapted to be directly connected to the electrical apparatus in which a surge to be recorded passes, the other` end of the other of the said electrodes being adapted to be electrostatically coupled to ground, and an electrically conducting electrostatic shield connected to the electrode which is adapted to be connected to the electrical apparatus, the said shield extending around the hollow member and being spaced from i yeries abutting one another to provide a hollow shell, a film of electrically conducting material on a face of each dish, the said films being spaced and insulated from one another, a partition of electrically non-conducting material adapted to divide the hollow shell at the abutting peripheries, a film of sensitized material on at least one face of the partition, a pair of` rod-type electrodes disposed normal to the dishes in substantial alignment with each other and having their adjacent ends spaced apart by the partition, each of the said electrodes having an outer end extending through one of the dishes, and being in electrical contact with the film of electrically conducting material on a face of the dish through which it extends, means for electrically` connecting the outer end of one of the electrodes to the electrical apparatus in which a surge to be recorded passes, and .means for grounding the outer end of the other electrode.

3. A surge recorder of the electrostatic photosensitive type for electrical apparatus, compris-I ing two concave dishes made of electrically nonconducting material disposed with their peripheries abutting one another to provide a hollow shell, a film of electrically conducting material on a face of each dish, the said films being spaced and insulated from one another, a partition of electrically non-conducting material adapted to 6 f i divide the hollow shell at the abutting peripheriles, .agfilm of sensitized material on each face ofthe partition, a'rod-ty'pe electrode extending normally through one of the said dishes and having one end in contact with one ofthe films of sensitized material, electrically conducting means to .secure .the other end of the said electrode to the electrical apparatus in whicha surge to be recorded passes, another rod-type electrode substantially in alignment with the first mentioned electrode and having one end extending through the other dish and in contact with the other nlm of sensitized material at a point opposite the point of contact of the first mentioned electrode with a lm, the end in contact with a lm of at least one of the electrodes being spring pressed, each of the electrodes being in electrical contact with the lm of conducting material on the dish through which it extends, an electrically conducting open ended hood connected to the first mentioned electrode at a point outside the hollow shell and extending around the said hollow shell and being spaced from the other electrode, the other end of the said other electrode being adapted to be coupled to ground.

4. A surge recorder of the electrostatic photosensitive type for electrical apparatus, comprising two concave dishes made of electrically nonconducting material disposed with their peripheries abutting one another to provide a hollow shell, a partition of electrically non-conducting material adapted to divide the hollow shell at the abutting peripheries, a film of sensitized material on each face of the partition, a rod-type electrode extending normally through onel of the said dishes and having one end in contact with one of the films, electrically conducting means to secure the other end of the said electrode to the electrical apparatus in which a surge to be recorded passes, another rod-type electrode substantially in alignment with the first mentioned electrode and having one end extending through the other dish and in contact with the other lm at a point opposite the point of contact of the first mentioned electrode with a film, the end in contact with a nlm of at least one of the electrodes being spring pressed, an electrically conducting open ended hood connected to the rst mentioned electrode at a point outside the hollow shell and being spaced from the other electrode and extending around the said hollow shell, the other end of the said other electrode being adapted to be coupled to ground, and a resistor of the order of 20 to 100 megohms connected between the hood and the said other electrode.

5. A surge recorder of the electrostatic photosensitive type for electrical apparatus, comprising two conducting members one of which is adapted to be connected to the electrical apparatus and one of which is a rod-type electrode, a non-conducting partition between the yconducting members, a film of sensitized material between the electrode and the partition and engaged by the electrode, an electrostatic shield of conducting material extending around and electrically connected to the conducting member which is adapted to be connected to the electrical apparatus and spaced from the other ccnducting member, and a resistor of the order of 20 to l0() megohms electrically connecting the two conducting members.

JOHN HENRY WAGHORNE.

(References on following page) REFERENCES CITED ANumber v j The following references are of record in the 111e of this patent: 210911521 UNITED STATES PATENTS 5 212611675 Number Name Date 2,269,225 1,526,770 Brain Feb. 1T, 1925 2,377,622 1,649,180 Peters Nov. 15, 1927 2,463,125

8 Name Date Foust June 17, 1930 Tanberg May 12, 1931 Pattison Aug. 31, 193'? Edler Nov. 4, 1941 Rich Jan. 6, 1942 Finzi June 5, 1945V Silver Apr. 26, 1949

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