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

Patent metadata

Field	Value
Publication number	US-10256013-B2
Application number	US-201715584676-A
Country	US
Kind code	B2
Filing date	May 2, 2017
Priority date	Jun 20, 2014
Publication date	Apr 9, 2019
Grant date	Apr 9, 2019

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:
a row of front portions of a plurality of arc attenuating boxes supported within the motor control center, the front portions being grouped together as a front cover, each front portion of the plurality of arc attenuating boxes being configured to be horizontally inserted over a free end of a respective one of a plurality of vertical bus bar phases in the motor control center;
a row of rear portions of the plurality of arc attenuating boxes supported within the motor control center, the rear portions being grouped together as a rear cover, each rear portion of the plurality of arc attenuating boxes being configured to be horizontally inserted over a rear end opposite to the free end of a respective one of the plurality of vertical bus bar phases;
the front cover and the rear cover being configured to join together with the front portion of the arc attenuating boxes fitting over the free end of the vertical bus bar phases and the rear portion of the arc attenuating boxes fitting over the rear end of the vertical bus bar phases, each arc attenuating box surrounding an individual one of the vertical bus bar phases;
each arc attenuating box being configured to provide a physical barrier to arc flash energy and gases intruding into an adjacent one of the arc attenuating boxes surrounding an adjacent one of the vertical bus bar phases, and
each arc attenuating box being open at its top and bottom to form a chimney along a respective vertical bus bar phase, to provide directed venting of arc flash energy and gases out of the motor control center.

2. The passive arc control system for a motor control center of claim 1 , further comprising:
a plurality of independently moveable, box-shaped shutters, each shutter being configured to align with the front portion and the rear portion of a respective one of the plurality of arc attenuating boxes, each box-shaped shutter having an opening through which a respective vertical bus bar phase passes within the respective arc attenuating box, each shutter being configured to slide horizontally along the respective vertical bus bar phase, away from an insulator cap on the free end of the respective vertical bus bar phase, in response to a force applied by a leading edge of a connector assembly of a motor control unit when the motor control unit is being connected to the respective vertical bus bar, each shutter being configured to slide horizontally along the vertical bus bar phase toward the insulator cap, in response to a force applied by a spring, when the motor control unit is disconnected from the vertical bus bar, each box-shaped shutter being open top to bottom, with the opening aligned with the top to bottom opening in the arc attenuating box, as part of the chimney formed along the vertical bus bar.

3. The passive arc control system for a motor control center of claim 2 , 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.

4. The passive arc control system for a motor control center of claim 2 , wherein the insulator cap is a coating of insulator material on the free end of the vertical bus bar.

5. The passive arc control system for a motor control center of claim 1 , further including 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 one of the vertical bus bars, when the connector assembly is moved toward the respective vertical bus bar.

Assignees

• Schneider Electric Usa Inc
• Richards Nathan

Inventors

• Romero Legorreta German
• Faber Tim
• Richards Walter J

Classifications

• H01H9/22

  for interlocking between casing, cover, or protective shutter and mechanism for operating contacts {(explosion-proof cases H01H9/045; built-in fuses and interlocking mechanisms H01H9/104; by automatic release of circuit breakers H01H71/126)} · CPC title

• H02B1/14

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

• H02B1/21

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

• H02B1/30

  Cabinet-type casings; Parts thereof or accessories therefor · CPC title

• H02B11/24

  Shutters or guards · CPC title