Circuit Breaker Interlock Preventing Backfeed
Solution Overview
Problem
In electrical systems without automatic transfer switches, human intervention can lead to the unintended connection of multiple power sources, risking back feeding, damage, and electrocution, as portable generators require manual switching between main and backup power sources.
Innovation Solution
An interlock article with movable handles and limiter plates associated with circuit breaker switches, ensuring that only one power source is connected at a time by configuring the switches between 'on' and 'off' positions, with limiter plates interacting to prevent simultaneous activation of adjacent switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If manual switching between main power source and back-up generator is used, then cost is reduced by eliminating automatic transfer switch, but safety is worsened due to possibility of inadvertent connection of multiple power sources
Solution Approach 1:
The patent introduces an interlock mechanism as an intermediary device between the main power source and back-up generator circuits. This interlock comprises a first actuator associated with the main power source and a second actuator associated with the back-up generator, where the actuators are mechanically interconnected to prevent simultaneous operation. The interlock serves as a mediator that enforces safety constraints while allowing manual switching operations.
Solution Approach 2:
The interlock mechanism is designed to automatically prevent inadvertent simultaneous connection of multiple power sources without requiring external monitoring or control systems. The mechanical interconnection between actuators creates a self-enforcing system where the physical state of one actuator automatically determines the available states of the other actuator, making the safety function self-service and eliminating the need for expensive automatic transfer switches.
2Reliability
If automatic transfer switch is installed to prevent simultaneous connection of power sources, then safety is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces an interlock mechanism as an intermediary device between the main power source and back-up generator circuits. This interlock comprises a first actuator associated with the main power source and a second actuator associated with the back-up generator, where the actuators are mechanically interconnected to prevent simultaneous operation. The interlock serves as a mediator that enforces safety constraints while allowing manual switching operations.
Solution Approach 2:
The interlock mechanism replicates the safety function of an automatic transfer switch through a simpler mechanical copying approach. Instead of using complex electronic sensing and automatic switching mechanisms, the patent creates a mechanical copy of the interlocking logic through physically interconnected actuators that mimic the protective behavior of automated systems at a fraction of the complexity and cost.
3Device complexity
If human intervention is used for switching between power sources, then device complexity is reduced, but reliability worsens due to human error in switching operations
Solution Approach 1:
The patent introduces an interlock mechanism as an intermediary device between the main power source and back-up generator circuits. This interlock comprises a first actuator associated with the main power source and a second actuator associated with the back-up generator, where the actuators are mechanically interconnected to prevent simultaneous operation. The interlock serves as a mediator that enforces safety constraints while allowing manual switching operations.
Solution Approach 2:
The interlock mechanism is designed to automatically prevent inadvertent simultaneous connection of multiple power sources without requiring external monitoring or control systems. The mechanical interconnection between actuators creates a self-enforcing system where the physical state of one actuator automatically determines the available states of the other actuator, making the safety function self-service and eliminating the need for expensive automatic transfer switches.
Data Source
AI summary
An interlock for a circuit breaker having a first circuit breaker switch and a second circuit breaker switch. The interlock includes a first actuator movably associated with the first circuit breaker switch, a first limiter plate and a first handle securely associated with the first actuator and the first limiter plate. The interlock further includes a second actuator movably associated with the second circuit breaker switch, a second limiter plate, and a second handle securely associated with the second actuator and the second limiter plate. The first limiter plate and second limiter plates are configurable between a first configuration and a second configuration. When the first plate is in the second configuration, the second plate is non-movably configured in the first configuration, and when the second plate is in the second configuration, the first plate is non-movably configured in the first configuration.