US2405457A - Coil winding for electric apparatus and method of making same - Google Patents

Description

A. T. SINKS Aug. 6, 1946.

COIL WINDING FOR ELECTRIC APPARATUS AND METHOD OF MAKING SAME Filed 0c'b..25, 1943 Inventor-z Allen "IT Sinks,

H15 1 Attor ney.

Patented Aug. 6, 1946 COIL WINDING FOR ELECTRIC APPARATUS AND METHOD OF MAKING SAME Allen T. Sinks, Beach Blufi, Mass, assignor to General Electric Company, a corporation of New York Application October 23, 1943, Serial No. 507,419

8 Claims.

My invention relates to a coil winding for an electrical induction apparatus and to a method of forming the coil winding.

Heretofore it has been customary to form some types of electrical induction apparatus such as instrument current transformers with a tunnel type porcelain body which includes a tubular shaped inner wall and a spaced outer wall forming a winding space. The outer Wall usually extends into a relatively long tubular member on the top of which is mounted the terminals of the transformer. Inside the winding space and between the spaced wall members there is provided a few turns of wire to form the primary winding of the transformer. Through the tunnel on the outside of the porcelain is placed the core winding leg and the low voltage secondary winding. It will be understood that the space between the porcelain walls inside the pot type porcelain is relatively narrow and some difliculty has been experienced in the past in winding the conductor around the inner porcelain body to provide the high voltage winding. This has usually been accomplished by taking an insulated conductor and working it around the inner body a suflicient number of times to form a plurality of turns so as to produce the high voltage winding. However, such prior methods have been susceptible of cracking or injuring the relatively hard surface of the porcelain and such prior methods are usually rather tedious and expensive.

It is therefore an object of my invention to provide an improved high Voltage primary winding for a pot type current transformer of the above mentioned type.

A further object of my invention is to provide an electric induction apparatus with an improved coil winding which is simple in construction and eflicient in operation.

A still further object of my invention is to provide an improved method for facilitating the forming of a high voltage Winding around a tubular body in the cavity of a pot type insulated transformer.

Further objects and advantages of my invention will become apparent from the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

In the drawing Fig. l is a side elevation in partial section illustrating a pot type instrument transformer which is provided with an embodiment of my invention; Fig. 2 is a perspective view of the pot type insulator employed in the construction of Fig. 1; Fig. 3 illustrates my improved method of winding the high voltage winding of the transformer illustrated in Fig. 1; and Fig. 4 is an exploded perspective view of a portion of the high voltage Winding employed in the construction of Fig. 1.

Referring more particularly to Fig. 1 of the drawing, I have illustrated an electrical induction apparatus which has particular application as a high voltage instrument current transformer which includes a pot type insulator II) having a cavity II, at the bottom of which there is provided a tubular shaped wall I2 and a spaced bottom wall I3 providing a winding space I l. The tubular shaped wall I2 is hollow so as to provide an opening or tunnel I5 through which extends a winding leg I6 of a core in the conventional manner. The core is formed in two halves with an outer yoke portion I! which connects with half of the winding leg I 6. The other half of the winding leg I6, it will be understood, connects with a yoke similar to I! and on the opposite side of the transformer. A base member I8 of suitable metallic material is provided which surrounds the core members and which supports the pot type insulator through a metallic flange member I9 which is in turn attached to the insulator in any suitable manner such as by cementing, as is indicated at 20. The top of the cavity I I is closed through a cover member 21 which is attached to the top of the insulator through a collar 22 which is in turn supported by a shoulder 23 of the insulator and is cemented, as is illustrated by the numeral 24. A pair of terminals 25 and 26 are provided on the cover which in turn connect to the high voltage primary winding, the construction of which will be described below. Low voltage terminals 21 are provided which are supported by the base I8 which are connected to a low voltage winding 28 through a conductor 29. The low voltage winding 28 surrounds the winding leg and is inside the tunnel I5.

In order to provide an improved high voltage winding arrangement, I provide a spool member 30 which is split and which is formed of two semicylindrical portions 3I and 32, as will be seen in detail in the exploded View of Fig. 4. These members may be made of any suitable material and are formed of conducting material such as copper for the reasons which will be apparent as the following description proceeds. The semi-cylindrical members 3| and 32 are placed around the tubular inner wall I2, as is illustrated in Figs. 1

e) and 3, with the abutting surfaces 33 slightly spaced and the surfaces as abutting. Suitable dowel pins which extend into holes 36 may be provided fOr properly positioning the semi-cylindrical members. In order that the spool will not provide a short-circuited turn around the Winding legs, the split spool is provided with a' longitudinal or axial discontinuity in the form of an insulating member 37 which is placed between the adjacent surfaces at 33.

In order to provide a convenient arrangement for winding a conductor around the spool to provide the high voltage winding, each of the semicylindrical portions 3! and 32 forming the spool is provided with spaced flanges 38 and 39 which have gear teeth it formed about the outer periphery thereof. Any suitable conducting material may be provided for the high voltage winding and in the construction illustrated it will be I seen that the high voltage conductor is in the form of a relatively wide and thin copper strip 4| which is wound off a suitable spool of the material 42. An end of the copper conductor 4| is attached to the spool in any suitable manner, such as by welding, as is indicated by the numeral 43. This connection may be made between the conduotor and the member 3! before the semi-cylindrical members are inserted in the porcelain. Also, as soon as one turn of the conductor is wound on the split spool, the semi-cylindrical members will be held together by the conductor. As the spool is wound up, interturn insulation may be provided between the turns of the conduotor by a suitable sheet of insulating material 14 which is wound off a spool 45.

In order to rotate the spool around the inner wall !2, I provide chain members 46 which mesh with the sprockets or teeth ii! on the peripheral flanges of the spool. It will be understood that a pair of continuous chains may be employed which mesh with each of the sprockets it, only one of which, however, is shown in Fig. 3. It is also to be understood that chains cooperate with suitable tooth wheels 55 which may be rotated by a suitable source of power (not shown) so as to rotate the spool. Thus by rotating the spool the copper conductor 4! with its insulation 44 will be wound around the tubular portions of the semicylindrical members 3! and 32, thus providing a continuous coil of concentric convolutions. It is to be understood that the spool is sufiiciently large so as to be able to rotate around the outer surface of the wall l2 and, to indicate this, there is shown a slight clearance between the wall l2 and spool 39.

In order to minimize binding between the inner surface of the spool and the outer surface of the wall 92, I provide a thrust member 59 which includes a rod having a pair of rollers 59 and 52 which roll on the outer surface of the spool and on the convolutions of the conductor as the con duotor is wound around the spool. Thus as the chain is rotated to produce a torque which in turn rotates the spool, the spool will tend to be forced upwardly against the bottom surface of the wall E2. Such rubbing, however, might tends to crack or injure the porcelain and in order to prevent this, the thrust member 563 with the rollers is provided which pushes downwardly with a force which may be made substantially equal to the upward force of the chain, thus allowing the spool to rotate relatively freely around the outer surface of the wall member Hi. This force is accomplished through a spring member 52' which is inside a tubular member 53 into which an end 4 of the rod 50 extends. The topsuriace of the tubular member 53 may be supported in any suitable manner, such as through a base 66 which in turn supports the rotatable wheels 65 which in turn cause the chains 46 to rotate.

My improved method of forming the high voltage winding around the tubular wall 12 at the bottom of the cavity of a pot type insulator, therefore, includes the steps of surrounding the tubular wall with the split spool with the conductor attached. The chain is then assembled for rotating the spool. A suitable amount of thrust is thereby provided through the thrust member 59 so that when the spool is rotated it will move relatively freely around the outer surface of the wall i2. After a suitable number of turns have been placed on the spool, the conductor may be cut and an end 55 attached to a conductor 55 which in turn connects to the terminal 25 or the conduotor M may continue up to and be attached to the terminal 25.

In order to provide the high voltage winding with another terminal, the terminal 26 is connected to the inner end of the high voltage wind ing through the spool. This may be accomplished in any suitable manner such as by providing a conductor lead 56' which has an inner end brazed. to the spool. It will be seen, particularly in Fig. 4, that both the semi-cylindrical members have on each of the flanges relatively flat portions 57 and, in order to facilitate the connection, a strap member 53 may be provided which bridges across the flat portions 57!. The strap 53 has depending legs 59 of suilicient length, which. is slightly longer than the thickness of the high voltage winding, so the outer convolutions will not touch the strap member 58 or are across during operation. Taped holes are provided in the flat portions 51, and suitable screws 50 attach the strap member to the axially spaced flanges of the semicylindrical portions 3!. This strap member pro vides a convenient place for attaching an end 5! of the conductor 55, as is illustrated in Fig. 1. It will be understood that the screws may be attached to the flat portions 51 by inserting a screw driver in the opening H of the porcelain when the spool is in position with the flat portions 51 facing upwardly. After the strap is assembled. the spool may be rotated a quarter of a turn so that the leads are attached to the winding substantially symmetrically. In. order to hold the high voltage winding snugly in the porcelain after assembly of the winding, a suitable filling compound may be put in the cavity H, as indicated by the line 62.

Although I have shown and described particular embodiments of my invention, I do not desire to be limited to the particular embodiments described, and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electrical induction apparatus including a pot type solid body of insulating material havintegral inner tubular shaped wall and an integral outer wall spaced from said inner wall providing a winding space between. said walls, a split spool of conducting material loose y surrounding said inner wall, a conductor wound around said spool with the inner end attached to said spool, a pair of terminals, and means for connecting one of said terminals to said spool and the other of the terminals to the outer turn of said wound conductor.

2. An electrical induction apparatus including a solid body of insulating material having a tubular inner wall and a spaced outer Wall providing a winding space, a spool of conducting material surrounding said inner wall, a conductor wound around said spool to form a winding, means for connecting the inner end of said conductor to said spool to form one terminal portion for said winding, and means for connecting a conductor to the outer turn of said winding to form another terminal.

3. An electrical induction apparatus including a solid body of insulating material having a tubular inner wall and a spaced outer wall providing a winding space, a split spool of conducting material loosely surrounding said inner wall, a conductor wound around said spool to form a winding, said split spool having an axially extending discontinuity so that it will not form a shortcircuited turn, one end of said conductor being attached to said spool so that said spool forms one terminal portion for the winding.

4. An electrical induction apparatus including a body of insulating material having a tubular inner wall and a spaced outer wall providing a winding space, a, pair of semi-cylindrical members of conducting material loosely surrounding said inner wall to form a winding spool, means for insulating adjacent surfaces of said members, a conductor wound around said spool to form a winding, said spool having axially spaced flanges, means including gear teeth formed about the outer periphery of said flanges for rotating said spool around said tubular wall for forming said winding.

5. An electrical induction apparatus including a body of insulating material having a tubular inner wall and a spaced outer wall providing a winding space, a pair of semi-cylindrical members of conducting material loosely surrounding said inner wall to form a winding spool, means for insulating adjacent surfaces of said members, a conductor wound around said spool in layers to form a winding, said spool having axially spaced flanges, means including gear teeth formed about the outer periphery of said flanges for rotating said spool around said tubular Wall for forming said winding, and means for attaching the inner end of said conductor to said spool.

6. An electrical induction apparatus including a body of insulating material having a tubular inner wall and a spaced outer wall providing a winding space, a pair of semi-cylindrical members of conducting material loosely surrounding said inner wall to form a winding spool, a conductor Wound around said spool to form a winding, said spool having axially spaced flanges, means including gear teeth formed about the outer periphery of said flanges for rotating said spool around said tubular Wall for forming said winding, and means for attaching one end of said conductor to said spool, a conducting bar bridging said flanges of said spool, a terminal, and means for connecting said terminal to said bar.

7. A winding for an electrical induction apparatus including a spool of conducting material, a conductor wound around said spool in layers with the inner end connected to said spool, means including said spool for providing one terminal connection for said winding, said spool having spaced flanges with gear integral teeth on the outer periphery thereof to provide means through which said spool may be rotated to wind on said conductor.

8. A method of forming a coil winding around a tubular wall at the bottom of the pot type insulated transformer including the steps of placing two semi-cylindrical metallic members in the cavity around the tubular wall to form a winding spool, placing a chain in the cavity around the spool for rotating the spool, rotating the spool, and placing a thrust member in the cavity and against the spool to prevent the spool from binding on the wall during rotation of the spool.

ALLEN T. SINKS.

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