CONDUCTOR RAIL ARC SUPPRESSION

Abstract: An arc suppression apparatus for attachment to the end of a conductor rail. The apparatus includes a ramp member (20) which defines a ramp surface which provides a gradually increasing gap between it and a contact element of a railway type vehicle and an insulating assembly (15) which is attachable to the ramp member to electrically isolate the ramp member (20) from the rail. The insulating assembly (15) can include a channel (19) into which any arc generated as the contact element disengages from the rail is drawn.

Description: Conductor Rail Arc Suppression This invention relates to conductor rails which are used to supply electrical power to vehicles such as underground trains and in particular to an arc suppression apparatus for use with such rails. Conductor rails are used to supply electrical energy to electrically powered vehicles such as underground trains. An underground train has a pick-up shoe which runs along the upper surface of a conductive rail to enable electrical energy to be conducted from the rail to the power unit of the train. Conductor rails have finite lengths and gaps exist between successive lengths of conductor rail. Thus at the end of a conductor rail, the pick-up shoe disengages from the rail and during such disengagement arcing can occur. Conventional conductor rails have a ramp at their end to provide a smooth and gradual disengagement of the shoe from the conductor rail, but even with such existing ramps arcing still occurs. Arcing is not necessarily a hazard in itself, but if it occurs in areas where combustible material such as dry leaves or litter exist then there is a potential fire hazard. The present invention is concerned with a ramp construction which is attachable to the end of a conductor rail and is designed to suppress the effects of arcing. According to a first aspect of the present invention there is provided an arc suppression apparatus for attachment to the end of a conductor rail to suppress the effect of arcing which can occur between the end of the rail and a contact element running along said rail, said apparatus comprising a ramp member which defines a ramp surface which in use provides a gradually increasing gap between it and a contact element as the contact element moves along its length, and an insulating assembly attachable to said ramp member and arranged so that in use it is located against said rail end to electrically isolate the ramp member from the rail end. The insulating assembly may include a channel into which any arc which is generated as the contact element disengages from the rail is directed. According to a second aspect of the present invention there is provided an arc suppression apparatus for attachment to the end of a conductor rail to suppress the effect of arcing which can occur between the end of the rail and a contact element running along the rail, said apparatus comprising an insulating assembly which is attachable to the end of the conductor rail so that in use it is located against the rail end, said insulating assembly including a channel into which any arc which is generated as the contact element disengages from the rail is directed. The channel may extend axially of the insulating member. The insulating material from which the insulating assembly is formed may be selected so that its wear characteristics are as far as possible similar to those of the conductor rail and ramp member. The material may be Permalli Mer20. .The width of the conductor rail may taper towards its end so that its end face has a width corresponding substantially to the lateral dimension of the channel in the insulating member. A tapered plate may be attached to the end of the conductor rail and project into said channel. The channel may be defined between a pair of plate-like elements formed of insulating material which are secured to opposite sides of the conductor rail at one end and to opposite sides of the ramp member at their other end. The invention will be described now by way of example only, with particular reference to the accompanying drawings. In the drawings: Figure 1 is a side elevation of the end of a conductor rail incorporating an arc suppression apparatus in accordance with an embodiment of the present invention; Figure 2 is a plan view of the arrangement of Figure 1; Figure 3 is a section along line A- A of Figure 1; Figure 4 is an exploded view of the assembly of Figure 3; Figure 5 is a section along the line B-B of Figure 1; Figure 6 is a side elevation showing the end of the conductor rail; Figure 7 is a plan view of the arrangement of Figure 6; Figure 8 is a side elevation showing part of the insulating member, and Figure 9 is a plan view of the member shown in Figure 8. Referring to the drawings the end of a conductor rail is shown at (10). The end of the conductor rail has a tapered portion shown at (11) and the end face of the tapered portion (11) has welded thereto a generally triangular plate (12) which is formed from mild steel. The plate (12) has formed therein two through holes (14). The conductor rail (10) and its attached plate (12) are connected to a ramp member (20) by an insulating assembly (15). The insulating assembly (15) includes a pair of generally planar elements (16, 17) which are secured to opposite sides of the plate (12) at one end thereof by means of huck bolts (18). The planar elements (16, 17) are formed from insulating material, preferably Permalli Mer20 and are spaced apart so that an axially extending channel (19) is formed therebetween. The other end of the planar members (16, 17) are secured to opposite side faces of the web (21) of the ramp member (20) by means of huck bolts (22). It will be seen that the upper surface (23) of the ramp member is generally flat and inclines downwardly and gradually towards its end (24). An in-fill member (25) is disposed between the planar members (16, 17) adjacent the end face of the ramp member (20). The in-fill member (25) which is formed of the same insulating material as the planar members (16, 17) is secured thereto by means of high tensile bolts (28). It will be seen that each planar member (15, 16) has a first relatively deep section (29) whose upper edge surface effectively forms a continuation of the conductor rail (10) and a second relatively shallow portion (30) which locates alongside the web of the ramp member (20). Also the material from which the insulating members (16, 17) are formed is designed to have wear characteristics which correspond as closely as possible to those of the conductor rail (10) and the ramp member (20). In use as a contact shoe moves towards the end of the conductor rail (10) it contacts the tapered portion (11) and moves on to the arc suppression apparatus which includes the insulating assembly (15). The insulating assembly (15) isolates the conductor rail (10) from the ramp member (20) and any arcing which occurs as the contact shoe leaves the conductor rail (10) is drawn down into the channel (19) between the insulating members (15, 16) by the triangular plate (12) which acts as an arc draw down surface. Thus, any arcing which occurs is confined and rapidly quenched in the space between the insulating members (16, 17) and this effectively minimises the likelihood of the arc affecting any external material such as leaves or litter. Thus this construction reduces considerably both the fire risk and environmental disturbance associated with arcing. By the time the contact shoe reaches the ramp (20) it has disengaged electrically from the conductor rail and therefore arcing will not occur beyond that stage. The ramp member (20) is retained to provide a mechanical runoff/smooth disengagement of the contact shoe from the conductor rail.

Claims: Claims: 1. An arc suppression apparatus for attachment to the end of a conductor rail to suppress the effect of arcing which can occur between the end of the rail and a contact element running along said rail, said apparatus comprising a ramp member which defines a ramp surface which in use provides a gradually increasing gap between it and a contact element as the contact element moves along its length, and an insulating assembly attachable to said ramp member and arranged so that in use it is located against said rail end to electrically isolate the ramp member from the rail end. 2. Apparatus according to claim 1, wherein the insulating assembly includes a channel into which any arc which is generated as the contact element disengages from the rail is directed. 3. An arc suppression apparatus for attachment to the end of a conductor rail to suppress the effect of arcing which can occur between the end of the rail and a contact element running along the rail, said apparatus comprising an insulating assembly which is attachable to the end of the conductor rail so that in use it is located against the rail end, said insulating assembly including a channel into which any arc which is generated as the contact element disengages from the rail is directed. 4. An arc suppression apparatus according to claim 4 including a ramp member which defines a ramp surface which in use provides a gradually increasing gap between it and said contact element as the contact element moves along its length, said insulating assembly, in use, being attached to the ramp member and electrically isolating it from the conductor rail. 5. Apparatus according to any one of claims 2 to 4, wherein the channel extends axially of the insulating member. 6. Apparatus according to any one of claims 1, 2, 4 or 5, wherein the insulating material from which the insulating assembly is formed is selected so that its wear characteristics are as far as possible similar to those of the conductor rail and ramp member. 7. Apparatus according to claim 6, wherein the material is Permalli Mer20. 8. Apparatus according to any one of claims 2 to 7, wherein the width of the conductor rail tapers towards its end so that its end face has a width corresponding substantially to the lateral dimension of the channel in the insulating member. 9. Apparatus according to claim 6, wherein a tapered plate is attached to the end of the conductor rail and projects into said channel. 10. Apparatus according to claim 2 or any one of claims 4 to 9, wherein the channel is defined between a pair of plate-like elements formed of insulating material which are secured to opposite sides of the conductor rail at one end and to opposite sides of the ramp member at their other end.

Inventors: NOLAN JOSEPH, NOLAN, JOSEPH
Applicants: INFRACO BCV LTD, NOLAN JOSEPH, INFRACO BCV LIMITED, NOLAN, JOSEPH
Application year: 2001
Main classification: B60M1
IPC codes: B60M1