RAT Auto-Deploy Logic Using AC Bus Tie Contactor Status

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Solution Overview

Problem

Conventional ram air turbine (RAT) automatic deployment systems in aerospace applications rely on human intervention when a generator source is online but not providing power, lacking automated logic for system configurations, which can lead to manual deployment uncertainties.

Innovation Solution

A system where auxiliary status contacts of generator line contactors and bus tie contactors are connected to a RAT automatic deployment controller, enabling automatic deployment of the RAT only when specific logical conditions are met, such as air mode detection and open generator or bus tie contactors, ensuring automated power distribution without human intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If conventional RAT auto-deploy systems rely on generator line contactor status only, then the system is simple to operate, but it cannot detect when generator is online but not providing power, requiring manual deployment

Engineering Contradiction:
ImproveRAT deployment automationVSAvoidcontrol system complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The control system monitors multiple contactor statuses (GLC1, GLC2, ALC, BTC1, BTC2) to perform a single function: determining whether RAT deployment is required. This multi-functional monitoring approach enables the system to detect all power distribution scenarios (generator offline, generator online but not powering, auxiliary generator status) using a unified control logic, achieving comprehensive automation without proportionally increasing system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system continuously monitors the status of multiple contactors and uses this feedback information to automatically determine when RAT deployment is necessary. The control system receives real-time status signals from GLC1, GLC2, ALC, BTC1, and BTC2 contactors, processes this feedback according to predefined logic, and automatically triggers RAT deployment when the generator is detected to be online but not providing power to AC buses, eliminating the need for manual intervention.

Inventive Principle:
Principle #23Feedback

2Reliability

If manual RAT deployment is required when generator is online but not powering, then human airmanship can recognize the condition, but deployment uncertainty and response time increase

Engineering Contradiction:
Improvedeployment reliabilityVSAvoiddeployment response time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The control system is pre-programmed with the logical conditions for RAT deployment based on contactor status patterns. When the generator is online but not providing power (detected through specific contactor status combinations), the system automatically triggers deployment without waiting for pilot recognition and action. This preliminary configuration of deployment logic ensures immediate response and eliminates uncertainty associated with manual judgment.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If the system monitors only generator line contactor status, then the control logic is simple, but it cannot distinguish between generator offline and generator online but not powering scenarios

Engineering Contradiction:
Improvesystem configuration detection capabilityVSAvoidcontactor monitoring complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The monitoring system is segmented into multiple independent contactor status sensors (GLC1, GLC2, ALC, BTC1, BTC2), each monitoring a specific point in the power distribution system. This segmentation allows the control system to detect different power distribution scenarios by combining information from individual contactor statuses, enabling distinction between generator offline and generator online but not powering conditions without requiring a single complex monitoring device.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3882157B1Ac bus tie contactor input into rat auto-deploy
Publication Date: 2023.08.30 HAMILTON SUNDSTRAND CORP
  • EP3882157B1 patent drawingFigure 1~2
  • EP3882157B1 patent drawingFigure 3~4

AI summary

A system includes a first AC bus (102) configured to supply power from a first generator (104). A first generator line contactor (GLC) (106) selectively connects the first AC bus to the first generator. A second AC bus (108) is configured to supply power from a second generator (110). A second GLC (112) selectively connecting the second AC bus to the second generator. An auxiliary generator line contactor (ALC) (114) is connected to selectively supply power to the first and second AC buses from an auxiliary generator (116). A first bus tie contactor (BTC) (118) electrically connects between the first GLC and the ALC. A second BTC (120) electrically connects between the ALC and the second GLC. A ram air turbine (RAT) automatic deployment controller (122) is operatively connected to automatically deploy a RAT (124) based on the combined status of the first GLC, the second GLC, the ALC, the first BTC, and the second BTC.