GB2285183A

GB2285183A - Shrouding busbars

Info

Publication number: GB2285183A
Application number: GB9326159A
Authority: GB
Inventors: Kenneth Neill
Original assignee: Square D Co
Current assignee: Schneider Electric USA Inc
Priority date: 1993-12-22
Filing date: 1993-12-22
Publication date: 1995-06-28
Also published as: GB9326159D0

Abstract

A motor control centre having vertically positioned busbars (10) located at the rear thereof, the busbars (10) being shrouded with electrically insulating material (11) except at access positions (12) to facilitate the plug-on of a saddle device, in use. Guard means comprises an electrically insulating guard member (13) which is mounted to close the access positions (12) when no saddle member is plugged-on thereto and to be moved to open the access positions (12) by a saddle member being moved towards the plug-on position thereat, in use. The guard member (13) may be mounted to span between the one end of each of a pair of pivotally mounted linkage members (14), the other ends of which are mounted to a counterweight (16) located behind the busbars (10). <IMAGE>

Description

IMPROVEMENTS RELATING TO ELECTRIC POWER DISTRIBUTION The invention relates to electric power distribution arrangements and more particularly to electric motor control centre power distribution arrangements for housing saddle devices.

Typical motor control centres comprise a group of motor starters contained in one or more vertical columns, each column containing a number of motor starters. Each starter is contained in a saddle which has reawardly projecting power supply connection members for plugging onto vertical busbars of the motor control centre.

Our copending United Kingdom patent application No. 2,258,568A discloses a saddle device with a lever actuation arrangement for facilitating ease of engagement of such saddle device with the busbars of a motor control centre. Further, our copending United Kingdom patent applications No. 93131161.3 and 93131162.1 disclose safety arrangements for use in saddle devices and motor control centres therefor.

However, in all presently known arrangements the busbars at the rear of motor control centres are unshrouded to accommodate plugging onto by the supply connection members of saddle devices. Although such busbars are at the rear of the motor control centre housing these do still form a hazard of possible shocks to engineers working with the equipment.

It is an object of the invention to obviate or mitigate the above problem.

According to the invention there is provided a motor control centre having vertically positioned busbars located at the rear thereof, the busbars being shrouded with electrically insulating material except at access positions to facilitate the plug-on of a saddle device, in use, and guard means comprising an electrically insulating guard member which is mounted to close the access positions when no saddle member is plugged-on thereto and to be moved to open the access positions by a saddle member being moved towards the plug-on position thereat, in use.

The guard means may comprise the guard member mounted to span between the one end of each of a pair of pivotally mounted linkage members, the other ends of which are mounted to a counterweight located behind the busbars and at least one of the linkage members may carry a cam bracket, a striker plate being slidably mounted on a runner member carried by racking of the motor control centre whereby entry of a saddle member engages the striker plate to move the cam bracket and linkage member(s) to raise the counterweight and lower the guard member to its open position.

The runner member may carry a pin which engages through a slot formed in the striker plate so as to limit travel of the striker plate between the open and closed positions of the guard member.

The striker plate may be resiliently urged to its position corresponding to the closed position of the guard member and this be achieved by a spring which is located to span pins carried on the striker plate and a bracket attached to the racking of the motor control centre.

The foregoing and further features of the invention may more readily understood from the following description of a preferred embodiment thereof, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a front elevational view of a part of a motor control centre showing busbar access positions open for use; Fig. 2 is a similar view to Fig. 1 but with the busbar access positions guarded; Fig. 3 is a side elevational view of part of a motor control centre with busbar access positions guarded, and Fig. 4 is a view similar to Fig. 3 with the busbar access positions open.

Referring now to Figs 1 and 2 of the drawings there is shown a front elevational view of the rear interior of a part of a motor control centre having three vertically extending busbars 10 which are each shrouded with electrically insulating material 11. The busbars 10 have access positions 12 where the shrouding 11 is cut away to enable the power connectors of a saddle device (not shown) to be plugged-on. Fig. 1 shows the access positions 12 open for use, with an electrically insulating guard member 13 in a lowered open position and Fig. 2 shows the access positions guarded, with the guard member 13 in an upper closed position.

Referring now to Figs 3 and 4 of the drawings guard member 13 is pivotally mounted between the first ends of two links 14 which are pivotally mounted at 15 to racking of the motor control centre. A counterweight 16 is located to span the other ends of links 14 behind busbars 10. A cam bracket 17 is attached to at least one of the links 14.

A striker plate 18 is slidably mounted on a runner member 19 and passes through a runner plate 20, the member 19 and plate 20 being carried by racking of the motor control centre. The runner member 19 carries a pin 21 which engages through a slot 22 formed in the striker plate 18 so as to limit travel of the striker plate 18 between the open and closed positions of the guard member 13. A spring 23 is located to span a pin 24 on striker plate 18 and a pin 25 on a bracket 26 carried on the racking of the motor control centre and is arranged to bias the striker plate 18 to its position in which guard member 13 is in its closed position.

In use, with the arrangement positioned as shown in Fig. 3, when a saddle device is moved to plug-on busbars 10, such device engages the left hand (outer) end of striker plate 18 and moves it to the right against the bias of spring 23 to engage cam bracket 17 and pivot link 14 counter-clockwise. This raises counterweight 16 and lowers guard member 13 from its closed position covering access positions 12 to its open position (Fig. 4) to allow the power connectors of the saddle device to engage busbars 10.

Conversely, when the saddle is removed from the motor control centre the arrangement moves from the position shown in Fig. 4, by the counterweight 16 and spring 23 pivoting link 14 clockwise to move guard member 13 back to its upper, closed position covering access position 12 and moving striker plate 18 leftwards (outwardly) to return to the position as shown in Fig. 3 ready for further use.

Hence the arrangement provides a "finger safe" closure for access positions of busbars in a motor control centre which can operate automatically under control of insertion and removal of a saddle device.

The guard member 13 is preferably fabricated of synthetic plastics material.

Claims

CLAIMS:

1. A motor control centre- having vertically positioned busbars located at the rear thereof, the busbars being shrouded with electrically insulating material except at access positions to facilitate the plug-on of a saddle device, in use, and guard means comprising an electrically insulating guard member which is mounted to close the access positions when no saddle member is plugged-on thereto and to be moved to open the access positions by a saddle member being moved towards the plug-on position thereat, in use.

2. A motor control centre as claimed in claim 1 wherein the guard means comprises the guard member mounted to span between the one end of each of a pair of pivotally mounted linkage members, the other ends of which are mounted to a counterweight located behind the busbars.

3. A motor control centre as claimed in claim 2 wherein at least one of the linkage members carries a cam bracket, a striker plate being slidably mounted on a runner member carried by racking of the motor control centre whereby entry of a saddle member engages the striker plate to move the cam bracket and linkage member(s) to raise the counterweight and lower the guard member to its open position.

4. A motor control centre as claimed in claim 3 wherein the runner member carries a pin which engages through a slot formed in the striker plate so as to limit travel of the striker plate between the open and closed positions of the guard member.

5. A motor control centre as claimed in claim 3 or 4 wherein the striker plate is resiliently urged to its position corresponding to the closed position of the guard member.

6. A motor control centre as claimed in claim 5 wherein a spring is located to span pins carried on the striker plate and a bracket attached to the racking of the motor control centre.

7. A motor control centre substantially as hereinbefore described with reference to the accompanying drawings.