Passive arc control with sequestered phases in a vertical bus system of a motor control center

Patent metadata

Field	Value
Publication number	US-9748024-B2
Application number	US-201414557817-A
Country	US
Kind code	B2
Filing date	Dec 2, 2014
Priority date	Jun 20, 2014
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

A passive arc control system for a motor control center 60 includes an arc attenuating box having sides separating adjacent vertical bus bar phases 54 , providing a physical barrier to arc flash energy. The box is open at its top and bottom forming a chimney 55 . A shutter assembly for each box includes an insulator cap 62 on a free end of the bus bar and an independently moveable, box-shaped shutter 64 that slides along the bus bar away from the insulator cap, when a device is connected to the bus bar. The shutter has an opening 65 through which the bus bar passes when the device is connected to the bus bar and an opening 55′ aligned with the box's chimney. The arc control system provides a high degree of arc protection for personnel working around open motor control centers and is highly modular and easy to construct.

First claim

The invention claimed is:

1. A passive arc control system for a motor control center, comprising:
an arc attenuating box surrounding an individual, vertical bus bar phase at a point of electrical connection between a circuit interrupting device and the vertical bus bar, sides of the arc attenuating box separating and sequestering one vertical bus bar phase from an adjacent vertical bus bar phase, the arc attenuating box being configured to provide a physical barrier to arc flash energy and gases intruding into an adjacent arc attenuating box surrounding an adjacent bus bar, the arc attenuating box being open at its top and bottom to form a chimney along the vertical bus bar to provide directed venting of arc flash energy and gases out of the motor control center; and
a shutter assembly including an insulator cap on a free end of the vertical bus bar and an independently moveable, box-shaped shutter composed of an insulator material, which slides horizontally within the arc attenuating box, the box-shaped shutter being configured to slide along the vertical bus bar away from the insulator cap, in response to a force applied by a leading edge of a connector assembly for the circuit interrupting device, when the device is being connected to the vertical bus bar, the main body of the box-shaped shutter having an opening through which the vertical bus bar passes when the device is connected to the vertical bus bar, the box-shaped shutter being open top to bottom, with the opening aligned with the top to bottom opening in the arc attenuating box, in both the connected and disconnected positions of the device, as part of the chimney formed along the vertical bus bar.

2. The passive arc control system for a motor control center of claim 1 , wherein the moveable, box-shaped shutter being configured to slide horizontally along the vertical bus bar toward the insulator cap, in response to a force applied by a spring, when the circuit interrupter device is disconnected from the vertical bus bar, the insulator cap being configured to closely fit within the opening in the shutter, thereby providing a physical barrier to debris, tools, and operator fingers by denying access to the vertical bus bar.

3. The passive arc control system for a motor control center of claim 1 , wherein the arc attenuating box includes a front portion that fits over the free end of the vertical bus bar, the front portion of the arc attenuating box having sides with a rear-facing mating surface, the arc attenuating box further including a rear portion that fits over a rear portion of the vertical bus bar, the rear portion of the arc attenuating box having sides with a front-facing mating surface, the rear-facing mating surface of the front portion of the arc attenuating box being configured to mate with the front-facing mating surface of the rear portion of the arc attenuating box to form the sides of the arc attenuating box.

4. The passive arc control system for a motor control center of claim 3 , wherein the insulator cap on the free end of the vertical bus bar is formed as an integral part of the front portion of the arc attenuating box.

5. The passive arc control system for a motor control center of claim 1 , wherein the insulator cap is a coating of insulator material on the free end of the vertical bus bar.

6. The passive arc control system for a motor control center of claim 1 , wherein a motor control unit configured to be inserted into the motor control center, the motor control unit including a circuit breaker, the motor control unit further having an exterior face of a rear wall of the motor control unit being configured to be located adjacent to the vertical bus bars when the motor control unit has been inserted into the motor control center, the motor control unit including movable connector assemblies for the motor control unit, each of the connector assemblies being configured to electrically connect to a respective vertical bus bar, when the connector assembly is moved toward the power bus.

7. The passive arc control system for a motor control center of claim 1 , wherein the connector assembly comprises a female connector and one or both of a connector protector surrounding the female connector, and a fixed shroud surrounding the connector protector.

8. The passive arc control system for a motor control center of claim 7 , wherein a leading edge of the female connector applies the force on the shutter to slide the shutter along the vertical bus bar away from the insulator cap, when in the connected position.

9. The passive arc control system for a motor control center of claim 7 , wherein a leading edge of the connector protector surrounding the female connector, applies the force on the shutter to slide the shutter along the vertical bus bar away from the insulator cap, when in the connected position.

Assignees

• Schneider Electric Usa Inc

Inventors

• Romero Legorreta German
• Faber Tim
• Richards Walter J J

Classifications

• H02B11/24

  Shutters or guards · CPC title

• H02B11/04 Primary

  Isolating-contacts, e.g. mountings or shieldings · CPC title

• H02B1/21

  Bus-bar arrangements for rack-mounted devices with withdrawable units · CPC title

• H01B17/42 Primary

  Means for obtaining improved distribution of voltage (capacitor-type lead-through insulators H01B17/28); Protection against arc discharges · CPC title

• H02B1/14

  Shutters or guards for preventing access to contacts (shielding of isolating-contacts in withdrawable switchgear H02B11/24) · CPC title