EP0972326A1

EP0972326A1 - Three-phase compact electrical bus structure

Info

Publication number: EP0972326A1
Application number: EP97920030A
Authority: EP
Inventors: John I. Ykema; John P. Barber
Original assignee: SPD Tech Inc
Current assignee: SPD Tech Inc
Priority date: 1997-04-01
Filing date: 1997-04-01
Publication date: 2000-01-19
Also published as: WO1998044612A1; CA2285912A1; AU2432497A; JP2001517420A

Abstract

A bus for transmitting three-phase electrical power comprises longitudinally elongated insulatively sandwiched lamina for carrying respective power phases with respective phase lamina having substantially equal cross-sectional areas at respective transverse locations within said sandwich.

Description

THREE PHASE COMPACT ELECTRICAL BUS STRUCTURE

Background of the Invention—Field of the Invention

This invention relates to electrical power transmission equipment, specifically to three-phase electrical power transmission equipment and to direct current electrical power transmission equipment.

Background of the Invention—Description of the Prior Art Means for transmitting three-phase electrical power are known and include conventional lines and cabling used in utility, industrial and nautical applications. Means for transmitting direct current electrical power are also known. A disadvantage associated with conventional transmission lines is that substantial inductance may be present.

An additional problem inherent in much of the prior art equipment for transmitting three-phase electrical power is lack of impedance balance between phases.

There is a continuing need in heavy duty industrial and nautical applications for three-phase electrical power transmission equipment having a high degree of impedance match among phases while having low inductance. Additionally, there is a continuing need for such equipment in small, light-weight form. Small size and light weight are especially desirable characteristics in three-phase power transmission equipment intended for nautical applications. There is also a continuing need in heavy duty industrial and nautical applications for direct current power transmission equipment having high efficiency with minimal component costs and exhibiting minimal cost for installation and replacement. Such direct current power transmission equipment should have minimum size, minimum mass and exhibit maximum survivability with low fire hazard in the event of a catastrophe; this is especially desirable for nautical applications.

Summary of the Invention

In one preferred embodiment this invention provides a bus for transmitting three-phase electrical power having longitudinally elongated insulatively sandwiched lamina for carrying respective power phases with respective phase lamina having substantially equal cross-sectional areas at respective transverse locations within the sandwich.

In another of its aspects in the preferred embodiment this invention provides apparatus for transmitting three-phase electrical power including a sandwich of insulatively layered longitudinally elongated lamina for carrying respective power phases in respective three-phase alternating disposition respecting a vertical direction along a lateral direction within the sandwich.

In yet another of its aspects in a preferred embodiment this invention provides a three-phase electrical power bus which includes a conduit. The bus further includes a plurality of electrically conductive longitudinally elongated members within the conduit. A first one of those members has a central portion and respective extremity portions extending substantially in a vertical direction from the central portion. The extremity portions are respectively offset relative to the central portion along a lateral direction.

Second ones of the elongated members of the plurality of electrically conductive longitudinally elongated members have respective portions offset from one another in the lateral direction by an amount substantially that of the amount of offset of respective first member extremity portions relative to the central portion of the first member.

The bus further includes third ones of the plurality of electrically conductive longitudinally elongated members where the third ones are of length in the vertical direction substantially that of the offset portions of the second ones of the elongated members and of the central and extremity portions of the first one of the elongated members.

In the bus as assembled the second members have respective portions which insulatively overlap the first member central portion on opposite sides. The second member offsets are substantially aligned with respective offsets of the first member so that remaining portions of the respective second members are proximate respective extremity portions of the first member.

Further, in the bus as assembled respective ones of the third members are substantially aligned in the lateral direction with the respective remaining portions of the second members and insulatively sandwich respective remaining extremity portions of the second members between such a respective third member and a respective extremity portion of the first member. In yet another of its aspects the preferred embodiment of the invention may be considered to provide a bus for transmitting three-phase electrical power which includes a plurality of electrically conductive longitudinally elongated lamina having transversely offset parts respecting one another and a plurality of electrically conductive longitudinally elongated lamina devoid of offsets. When assembled, the bus has lamina of the pluralities nested together with each of the offsets being transversely aligned with an offset of another member of the first plurality and with a lateral extremity of a lamina of the second plurality.

The lamina carrying respective phases of the three- phase electrical power are in an overlapping insulated sandwich disposition with lamina carrying each of the phases having substantially equal transverse cross- sectional area proximate the exterior of the lamina sandwich. Similarly, lamina carrying each of the phases have substantially equal transverse cross-sectional area at respective transverse locations within the lamina sandwich. Most desirably, the offsets in the lamina are perpendicular.

When assembled into the bus, the lamina of the second plurality preferably extend transversely to the direction of offset substantially the same length as parts of lamina of the first plurality on respective sides of the offsets. Most preferably, offset of respective parts of the lamina of the first plurality exceeds thickness of the lamina of the first plurality in the direction of offset. In yet another of its aspects, in the preferred embodiment this invention provides apparatus for connecting respective sections of a bus for transmitting three-phase electrical power where the apparatus includes male and female sections. The male section preferably includes a plurality of longitudinally elongated extendable pins arranged in horizontal and vertical rows for transmitting the respective phases. Pins carrying each of the phases are respectively preferably generally vertically and horizontally adjacent to pins for respectively carrying respective ones of the remaining two phases. The male section preferably further includes manually operable means for extending and retracting the pins into and out of connecting disposition with a female section of the connecting apparatus. The female section preferably includes spring- loaded or otherwise radially biased radially expandable receptacle members for receiving respective ones of the pins when extended from the male section. The receptacle members are preferably arranged in horizontal and vertical rows for carrying each of the respective phases, with receptacle members carrying each of the phases respectively being vertically and horizontally adjacent to receptacles for respectively carrying the respective two remaining phases.

In the preferred embodiment of the connector aspect of the invention the receptacle members preferably comprise a plurality of longitudinally elongated leaves which are circularly arranged about a longitudinal axis and include outwardly facing concavities defining a transverse annular recess around the exterior of the circularly arranged leaves. The receptacle means further preferably include resilient means residing within the recesses for biasing the leaves radially inwardly.

Most desirably, the receptacle members further include sleeves for receiving respective ones of the pins including annular lips around the sleeve exteriors with the leaves having an inwardly curving hook at a longitudinal extremity remote from the male section. The hook engages the exterior lip of the sleeve.

Desirably, the male section includes sleeves electrically connecting with respective power conductors of the bus, where the pins slidably reside within the sleeves.

In the preferred embodiment of the connection means, the manually operable means for extending and retracting the pins further includes a shaft which is manually rotatable about a transverse axis and means, preferably in the form of two-bar linkage, for converting rotation of the shaft into longitudinal motion and applying such longitudinal motion to the pins to extend or retract the pins according to the direction of rotation of the shaft. In the preferred embodiment of the connection means, the apparatus may further be considered to include longitudinally elongated extendable male members for carrying each phase of three-phase electrical power, means for extendably engaging and retractably disengaging the male members with and from female members of the connection apparatus, where the female members include spring-loaded means for resiliently releasably receivingly engaging respective male members for transmitting each of the respective phases of three- phase electrical power.

Brief Description of the Drawings Figure 1 is a transverse cross-sectional view of the preferred embodiment of a bus for transmitting three-phase electrical power manifesting aspects of the invention.

Figure 2 is a transverse cross-sectional view of the preferred embodiment of a bus for transmitting DC electrical power manifesting aspects of the invention. Figure 3 is a partially sectioned side view of a preferred embodiment of apparatus for connecting respective sections of a bus for transmitting three- phase electrical power manifesting aspects of the invention, showing portions of the connecting means extended in connecting disposition and other portions of the connecting means retracted from the connection position.

Figure 4 is a partially sectioned side view of a preferred embodiment of apparatus for connecting respective sections of a bus for transmitting three- phase electrical power manifesting aspects of the invention, similar to Figure 3, showing respective male and female parts of apparatus for connecting respective sections of the bus for transmitting three-phase electrical power. Figure 5 is a top view of the apparatus of Figure 4 taken as if the upper portions of the housings for the connecting apparatus of Figure 4 had been removed.

Figure 6 is a broken view illustrating the manner in which the housing and the connecting apparatus are connected by a bus for transmitting electrical power.

Figure 7 is an end view of a female section of the preferred embodiment of apparatus for connecting respective sections of a bus for transmitting three phase electrical power looking from the left hand side of Figure 6 as indicated by arrows 7-7 in Figure 6.

Numbers in the drawings correspond to numbers in the following description.

Description of the Preferred Embodiments and Best Mode Known for Practicing the Invention Referring to Figure 1 there is illustrated a preferred embodiment of a bus for transmitting three- phase electrical power manifesting aspects of the invention. The preferred embodiment of the three-phase power transmission bus is designated generally 10 and includes a conduit 12 filled with insulator material designated generally 14 and conductive means designated in Figure 1 but described in detail below.

Conduit 12 includes two sections, an upper element 400 and a lower element 402, which fit together as illustrated, with section 400 fitting generally within section 402 in a press-fit assembly. Upper element 400 has a generally planar top 404 and two sides extending transversely to the planar top. Lower element 402 has a generally planar bottom 406 and two generally planar sides extending transversely to the planar bottom.

The directions in the following discussion are taken with respect to Figure 1. The vertical direction is referred to as vertical, the horizontal direction is referred to as lateral, and the direction perpendicular to the paper is referred to as longitudinal.

The conductive means includes a plurality of electrically conductive longitudinally elongated elements disposed within conduit 12. Preferably, the conductive means includes a double-offset central element 410, two single-step elements 420, 421 and two straight elements, 440, 441.

As illustrated in Figure 1, central element 410 has a two-step shaped cross-section. Central element 410 has a middle portion 412 and two offset extremity portions 414, 415. Preferably middle portion 412 and extremity portions 414, 415 extend laterally, parallel to one another and are substantially the same length and thickness. Extremity portions 414, 415 are offset vertically in opposite directions and are connected to middle portion 412 by angled sections.

As illustrated in Figure 1, both single-step elements 420, 421 have a single-step shaped cross- section. The step shaped cross-section is configured so that single-step elements 420, 421 correspond to central element 410 in a nesting relationship. In this relationship, single-step elements 420, 421 are located on opposing sides of central element 410. Each single- step element 420, 421 comprises an intermediate portion 424, 425 and an offset portion 428, 429 joined by a preferably angled portion.

To properly nest with central element 410, intermediate portions 424, 425 of respective single- offset elements 420, 421 are parallel to and substantially the same length and thickness as middle portion 412. Additionally, offset portions 428, 429 are parallel to and substantially the same length and thickness as corresponding extremity portions 414, 415 of central element 410. The third conductive elements are straight elements 440, 441. Straight elements 440, 441 correspond to single-step elements 420, 421 in a nesting relationship, in which straight element 440 is adjacent to and in nesting relation with single-step element 420 and straight element 421 is adjacent to and in nesting relation with single-step element 441. Preferably, straight elements 440, 441 are parallel to and substantially the same length and thickness as respective extremities 414, 415. With the above nesting configuration, each of the conductive element is a separate lamina, which is stacked within conduit 12 as follows: Within the conduit, straight element 440 is located adjacent the right side of conduit 12 and adjacent planar bottom 406 of lower conduit element 402. Single-step element 420 overlaps straight element 440, so that offset portion 428 is adjacent the right side of conduit 12 and vertically separated by insulation from straight element 440 and intermediate portion 424 is adjacent planar bottom 406 and laterally separated by insulation from straight element 440.

Double-offset central element 410 overlaps single- step element 420, so that extremity 414 is adjacent the right side of conduit 12 and planar top 404 and is vertically separated by insulation from offset portion 428. In this relation, middle portion 412 is vertically separated from intermediate portion 424 of single-step element 420 and is laterally separated by insulation from offset portion 428. Extremity 415 is adjacent the left side of conduit 12 and planar bottom 406. Single-step element 421 overlaps extremity portion 415 and middle portion 412 of central element 410. In this way, offset portion 429 is adjacent the left side of conduit 12 and vertically separated by insulation from extremity portion 415. Intermediate portion 425 is adjacent planar top 404 and vertically separated by insulation from middle portion 412.

Straight element 441 overlaps offset portion 429 of single-step element 421. In this way, straight element 441 is adjacent the left side of conduit 12 and planar top 404, and vertically separated by insulation from offset portion 429.

Preferably the insulation separating each portion of the lamina that are vertically overlapping is less than the thickness of each respective portion. For example, offset portion 429 of single-step element 421 overlaps extremity portion 415 of central element 410. Preferably the insulation separating offset portion 429 from extremity 415 is less than the thickness of either offset portion 429 or extremity 415.

Preferably the three phase power is connected to the conductive means so that each phase passes through an element or combination of elements having equal cross-sectional area. Preferably, the three phases are connected as follows: one phase is connected to central element 410; the second phase is connected to single- step element 420 and straight element 441; and the third phase is connected to single-step element 421 and straight element 440. When connected in this manner, each side of conduit 12 is adjacent a conductor for each phase of power.

Figure 2 illustrates another embodiment of the modular bus, which is used for transmitting direct current power. The conduit 12 is configured in the same manner as the conduit used in the three-phase power transmission bus described above. The preferred embodiment of the DC power transmission bus is designated generally 10' and includes a conduit 12 filled with insulator material designated generally 14 and conductive means comprising positive conducting element 510 and negative conducting element 520.

Positive element 510 and negative element 520 are longitudinally elongated within conduit 12. Both elements are also laterally elongated, and are preferably the same lateral width. Each element has generally parallel upper and lower surfaces, positive element 510 having upper surface 512 and lower surface 514, negative element having upper surface 522 and lower surface 524. Preferably, the positive and negative elements have curved sides 516 and 526 respectively.

Insulation 14 is provided around the positive and negative elements, spacing them from each other and from conduit 12. Insulation 14 comprises five portions: three laterally elongated blocks, namely upper block 530, intermediate block 532, lower block 534, and two vertically elongated side blocks 536. Each block is longitudinally elongated within conduit 12.

Upper block 532 is separates positive element 510 from planar top 504 of conduit 12 by facingly contacting planar top 504 and upper surface 512 of positive element 510. Intermediate block 534 separates positive element 510 from negative element 520 by facingly contacting lower surface 514 of positive element and upper surface 522 of negative element. Lower block 534 separates negative element 520 from planar bottom 406 of conduit 12 by facingly contacting lower surface 524 of negative element and planar bottom. Side blocks 536 extend transversely respecting positive and negative elements 510 and 520, separating the elements from the sides of conduit 12. By contacting both elements and the three laterally elongated insulative blocks, and facingly contacts planar top 404 and planar bottom 406, each of side blocks 536 facingly contacting a different side of conduit 12, i.e. a right side or a left side. Referring now to Figures 3-7, a bus connector is designated generally 600. Bus connector 600 is used to connect sections of three-phase power transmission bus 10 described above, thereby allowing bus 10 to be extended in sections. The bus connector has a male connector 602 and a female connector 604 that connect with respective male and female connectors on adjoining sections of bus 10 as shown in Figures 3 and 4.

Figure 4 illustrates a cross-sectional view of bus connector 600, showing the male connector 602 at the end of one section and the female connector 604 at the end of an adjoining section. Male connector 602 comprises a series of pins 610 that can be extended or retracted through a series of receptacles 620 via a series of levers 615. Female connector 604 comprises the same receptacles 620, but does not have pins 610 or levers 615. To distinguish the receptacles in the following description female receptacles are designated as 620'.

In Figure 3 the upper pin 610 is shown in the extended position, engaging a corresponding female connector 604 in an adjoining connector. The lower pin

610 is shown in the retracted position in which there is no contact between the pin and the adjoining connector.

Lever 615 operates as a slider-crank mechanism, being rotated by a shaft 616. The rotation of shaft 616 in one direction causes lever 615 to extend pin 610 through receptacle 620. The opposite rotation causes lever 615 to retract pin 615. A lever stop 617 is provided to prevent lever 615 from rotating beyond the fully extended position. As illustrated in Figure 7, the male connector comprises two vertically separated horizontal rows of individual connectors. As shown in Figure 5, the levers 615 for each horizontal row are all connected to a single shaft 616 so that each horizontal row of levers rotates simultaneously. The conductive elements of bus 10 are designated generally 630 in Figure 4. A bracket 612 provides an electrical connection between each element 630 and a corresponding receptacle 620. Preferably, each bracket 612 is connected to one element 630 and two receptacles 620. The receptacles are configured so as to contact pins 610. When pin 610 extends into a receptacle in an adjoining female connector, an electrical connection is made between the pin and the receptacle of the female connector. In this way, electrical connection is made between adjoining section of three-phase power transmission bus 10.

As mentioned above, pin 610 slides within receptacle 620.

Preferably receptacle 620 is a generally bulbous- shaped longitudinally elongated shell, so that the base of the receptacle has a larger interior area than the area near the top. An opening through the top and the base of receptacle 620 allows pin 610 to slide through the receptacle. Preferably the base flares outwardly to provide an interior area large enough for a sleeve 626 having an annular lip.

Sleeve 626 resides within receptacle 620 to guide pin 610. Beyond sleeve 626, toward the top, receptacle 620 tapers inwardly, providing an interior area smaller than the sleeve so that the sleeve is engaged within the receptacle. Receptacle 620 also flares outwardly at the top opening, creating a lip 625.

Preferably, receptacle 620 has at least one and preferably two outwardly facing convex annular recesses 624. Recesses 624 are transverse respecting the longitudinal axis of receptacle 620 and are large enough to receive a resilient means such as a coil spring 628. Coil springs 628 urge receptacle 620 inwardly to ensure contact between the receptacle and pin 610. Receptacle 620 is preferably not a unitary piece. Instead, receptacle 620 preferably comprises a series of longitudinally elongated leaves circularly arranged about a longitudinal axis. This configuration is illustrated in Figure 7 which shows the end view of the series of leaves.

Referring further to Figure 7 , the arrangement of the individual receptacles can be seen with reference to the cross-section of the conductive elements 630 of three-phase power transmission bus 10. As described previously, three-phases of electricity flow through bus 10. In the present instance, twelve receptacles 620 are arranged on six brackets 612, to form six groups of two receptacles each.

Three groups designated Gl, G2 , G3 form an upper horizontal row of six receptacles, and three groups G4 ,

G5, G6 form a lower horizontal row of six receptacles. Groups Gl and G5 preferably conduct one phase of electricity; groups G2 and G6 preferably conduct a second phase of electricity; and groups G3 and G4 preferably conduct the third phase of electricity.

Referring now to Figures 3 and 4, adjoining sections of three-phase power transmission bus 10 are connected as follows: The outer casing of male connector 602 is brought into contact with a flange on the outer casing of female connector 604 so that the flange overlaps the outer casing of male connector 602. The casings of the two connectors are then coupled by such means as bolting or welding.

Once the casings of the adjoining connectors are coupled, the shafts 616 for the upper and lower rows of levers 615 are rotated. Rotating shafts 616 cause levers 615 to extend pins 610 out of receptacles 620 to engage corresponding adjoining receptacles 620' in female connector 604. Preferably, the conductive elements of the invention are fabricated of copper. However, aluminum or even silver may also be used as may other conductive materials.

A major advantage provided by the invention in all of its embodiments is that all components of the particular current being carried are in one compact package as opposed to use of conventional individual cables. Conventional cables must be provided with stuffing tubes where they pass through a wall or bulkhead. In the instant invention, the bus is preferably fabricated effectively as a piece of or built into the wall or bulkhead. The bus is preferably welded in place after being checked for structural integrity and, in nautical applications, for water-tight integrity.

In the invention the candidate materials for contructing the conduit are materials such as steel, aluminum, plastic or carbon fiber composites. Steel may be preferred in nautical applications, to protect the bus from shrapnel. The insulative members separating the conductive elements may be epoxy, polyester, teflon, nylon or even ceramic. In this regard, inorganic materials are preferable to avoid any charring in the event of dielectric effects. Inorganic materials do not produce smoke since there is no charring.

Respecting the facingly contacting surfaces of the respective conductive and insulative members, there is no need for bonding at such surfaces for purposes of achieving mechanical strength characteristics; however, there may bonding provided at such surfaces for thermal conductance at such interfaces.

Claims

The following is claimed:

1. A bus for transmitting three-phase electrical power comprising longitudinally elongated insulatively sandwiched lamina for carrying respective power phases with respective phase lamina having substantially equal cross-sectional areas at respective transverse locations within said sandwich.

2. A bus for transmitting three-phase electrical power comprising a sandwich of insulatively layered longitudinally elongated lamina for carrying respective power phases in respective three-phase alternating disposition, respecting a vertical direction, along a lateral direction within said sandwich.

3. A three-phase electrical power bus comprising: a. a conduit; b. a plurality of electrically conductive longitudinally elongated members within said conduit; i. a first one of said elongated members having a central portion and respective extremity portions extending in a lateral direction therefrom, said extremity portions being respectively vertically offset relative to said central portion; ii. second ones of said elongated members having respective portions vertically offset from one another by an amount substantially that of offset of respective first member extremity portions relative to said central portion; and iii. third ones of said elongated members being of length in said lateral direction substantially that of said portions of said second ones of said elongated members and of said central and extremity portions of said first elongated member; said second members having respective portions insulatively overlapping said first member central portion on opposite sides; second member offsets being substantially aligned with respective offsets of said first member so that remaining portions of respective second members are proximate respective extremity portions of said first member; respective third members being substantially vertically aligned with said respective remaining portions of said second members and insulatively sandwiching respective remaining extremity portions of said second members between respective third members and respective extremity portions of said first member.

4. A bus for transmitting three-phase electrical power comprising: a. a plurality of electrically conductive longitudinally elongated lamina having transversely offset parts respecting one another; b. a plurality of electrically conductive longitudinally elongated lamina devoid of offsets; and c. lamina of said first and second pluralities being nested together, each of said offsets being transversely aligned with an offset of another member of said first plurality and with a lateral extremity of a lamina of said second plurality.

5. The bus of claim 4 wherein said lamina carrying respective phases of said three-phase electrical power are in overlapping insulated sandwiched disposition with lamina carrying each of said phases having substantially equal transverse cross- sectional area proximate the exterior of said lamina sandwich.

6. The bus of claim 4 wherein said lamina carrying respective phases of said three-phase electrical power are in vertically overlapping insulated sandwiched disposition with lamina carrying each of said phases having substantially equal transverse cross-sectional area at respective transverse locations within said lamina sandwich.

7. The bus of claim 6 wherein lamina of said second plurality extend transversely to the direction of offset substantially the same length as parts of said lamina of said first plurality on respective sides of said offsets.

8. The bus of claim 7 wherein offset of respective parts of lamina of said first plurality are a given thickness and are vertically separated from said lamina of said second plurality a distance greater than said thickness.

9. Apparatus for connecting respective sections of a bus for transmitting three-phase electrical power comprising: a. a male section including: i. a plurality of longitudinally elongated extendable pins arranged in horizontal and vertical rows for transmitting said respective phases, pins for carrying each of said phases respectively being vertically and horizontally adjacent to pins for respectively carrying respective remaining phases; ii. manually operable means for extending and retracting said pins into and out of connecting disposition with a female section of said apparatus; b. said female section including a plurality of spring-loaded radially expandable receptacle members for receiving respective ones of said pins when extended from said male section, arranged in horizontal and vertical rows for carrying each of said respective phases.

10. The connector of claim 9 wherein said receptacle members comprise: a. a plurality of longitudinally elongated leaves circularly arranged about a longitudinal axis, including outwardly facing concavities defining an outwardly facing transverse annular recess around the exterior of said circularly arranged leaves; and b. resilient means residing within said recess for biasing said leaves radially inwardly.

11. The connector of claim 10 wherein said receptacle members further comprise: a. sleeve means for receiving respective ones of said pins, including an annular lip about the sleeve exterior; and b. said leaves having an inwardly curving hook at a longitudinal extremity thereof remote from said male section for engaging said exterior lip of said sleeve.

12. The connector of claim 9 wherein said male section includes: a. sleeve means electrically connecting with respective power conductors of said bus and having said pins slidably resident therewithin; wherein said manually operable means for extending and retracting said pins further comprises: b. shaft means manually rotatable about a transverse axis; and c. means for converting rotation of said shaft into longitudinal motion and applying the same to said pins.

13. Apparatus for connecting respective sections of a bus for transmitting three-phase electrical power comprising: a. longitudinally elongated extendable male members for carrying each of said phases; b. means for extendably engaging and retractably disengaging said male members with and from female members of said connection apparatus; c. said female members including spring-loaded means for resiliently releasably receivingly engaging respective male members for transmitting each of said respective phases of three-phase electrical power.

14. Apparatus for connecting respective sections of a bus for transmitting D.C. electrical power, comprising: a. a male section including: i. a plurality of longitudinally elongated extendable pins arranged in rows for transmitting respective polarities; ii. manually operable means for extending and retracting said pins into and out of connecting disposition with a female section of said apparatus; b. said female section including a plurality of spring loaded radially expandable receptacle members for receiving respective pins when extended from said male section, arranged in rows for carrying said respective polarities.

15. The connector of claim 14 wherein said receptacle members comprise: a. a plurality of longitudinally elongated leaves circularly arranged about a longitudinal axis, including outwardly facing concavities defining an outwardly facing transverse annular recess around the exterior of said circularly arranged leaves; and b. resilient means residing within said recess for biasing said leaves radially inwardly.

16. The connector of claim 15 wherein said receptacle members further comprise: a. sleeve means for receiving respective ones of said pins, including an annular lip about the sleeve exterior; and b. said leaves having an inwardly curving hook at a longitudinal extremity thereof remote from said male section for engaging said exterior lip of said sleeve.

17. The connector of claim 14 wherein said male section includes: a. sleeve means electrically connecting with respective power conductors of said bus and having said pins slidably resident therewithin; wherein said manually operable means for extending and retracting said pins further comprises: b. shaft means manually rotatable about a transverse axis; and c. means for converting rotation of said shaft into longitudinal motion and applying the same to said pins.

18. Apparatus for connecting respective sections of a bus for transmitting D.C. electrical power comprising: a. longitudinally elongated extendable male members for carrying each of said polarities; b. means for extendably engaging and retractably disengaging said male members with and from female members of said connection apparatus; c. said female members including spring-loaded means for resiliently releasably receivingly engaging respective male members for transmitting said respective polarities;

19. A modular direct current bus, comprising: a. an axially elongated conduit comprising a generally planar top, a generally planar bottom, a right side and a left side, said right and left sides extending transverse said planar top and said planar bottom; b. axially elongated positive and negative conductive members within said conduit, said conductive members having generally planar and parallel upper and lower surfaces, and curved sides; c. axially elongated insulative means for maintaining said conductive members spaced from said conduit and from each other, comprising: i. an upper laterally elongated insulative block facingly contacting said planar top and said upper surface of said positive conductive member; ii. an intermediate laterally elongated insulative block facingly contacting said lower surface of said positive conductive member and said upper surface of said negative conductive member; iii. a lower laterally elongated insulative block facingly contacting said lower surface of said negative conductive member and said planar bottom; iv. two side vertically elongated blocks extending transverse said upper, intermediate and lower insulative blocks, both of said side blocks contacting said upper, intermediate and lower insulative blocks, said side blocks facingly contacting said planar top and said planar bottom, one of said side blocks facingly contacting said conduit right side, the remaining side block facingly contacting said conduit left side.