Circuit Breaker Interlock for Manual and Motorized Racking

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Solution Overview

Problem

Existing interlock systems for circuit breakers are not compatible with both manual and automatic racking assemblies, leading to potential damage and unsafe operation when using integral motors.

Innovation Solution

An interlock system with an actuatable motor control and a movable access door that ensures the separable contacts are in an open configuration before the integral motor operates, preventing damage and ensuring safe transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the interlock system uses a movable access door to control manual racking assembly access, then the separable contacts can be ensured to be in open configuration during manual operation, but the system becomes incompatible with automatic racking assemblies using integral motors

Engineering Contradiction:
Improvesafety of separable contacts configurationVSAvoidcompatibility with both manual and automatic racking assemblies
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The access door is made movable rather than fixed, allowing it to dynamically change position between open and closed states. This enables the door to adapt to different operational modes (manual vs automatic) while maintaining the safety function of ensuring separable contacts are in the open configuration during transitions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The access door acts as an intermediary element between the operator and the manual racking assembly socket. When closed, it prevents direct access to the socket, thereby mediating the interaction and ensuring that racking operations only occur when separable contacts are in the safe open configuration.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the access door blocks access to the manual racking assembly socket during automatic operation, then the integral motor can operate safely, but the interlock system may be damaged due to incompatible operation modes

Engineering Contradiction:
Improvesafe operation of integral motorVSAvoidinterlock system compatibility management
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The access door is closed in advance before automatic operation begins, preventing any manual intervention during motor-driven racking transitions. This preliminary action ensures that the integral motor operates without risk of damage from incompatible manual operations while maintaining safety.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the interlock system allows manual operation when the access door is open, then ease of manual racking is achieved, but potential damage occurs when automatic motor operation is attempted under the same conditions

Engineering Contradiction:
Improvemanual racking accessibilityVSAvoidprotection against interlock system damage
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The access door serves as a preliminary protective measure that prevents manual operation of the racking assembly when the integral motor is intended to operate. By blocking access to the socket, it preemptively eliminates the risk of damage from incompatible simultaneous operations.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP3903335B1Interlock system for a circuit breaker system
Publication Date: 2026.01.28 EATON INTELLIGENT POWER LTD
  • EP3903335B1 patent drawingFigure 1
  • EP3903335B1 patent drawingFigure 1A
  • EP3903335B1 patent drawingFigure 2

AI summary

An interlock system (100) including an actuatable motor control assembly (110), a movable access door (74) and an interlock assembly (120). The actuatable motor control assembly (110) is structured to energize and de-energize a racking assembly motor (56). The movable access door (74) is structured to move between an open, first position wherein the access door (74) does not block access to a manual racking assembly socket (72), and, a closed, second position wherein the access door (74) blocks access to the manual racking assembly socket (72). The interlock assembly (120) is structured to detect the configuration of the separable contact assembly (19) and the position of the access door (74), and, to actuate the motor control assembly (110) so as to energize the motor (56) only when the separable contact assembly (19) is in an open, first configuration and when the access door (74) is in a closed, second position.