Railroad Switch Machine Solid-State Relay Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Railroad switch machines face reliability issues due to contact erosion and mechanical malfunctions, which can lead to unintended track movements and potential derailments, and existing solutions are costly and require frequent replacement of vital relays.

Innovation Solution

A switch machine design featuring bi-polar relays and solid-state components that prevent simultaneous closure of contacts, ensuring directional accuracy and incorporating a current-integration mechanism to protect the motor from excessive current, thereby reducing the risk of arcing and thermal damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electromechanical relays are used for controlling switch machines, then the switching function is achieved, but contact erosion occurs due to arcing between contacts

Engineering Contradiction:

Improveswitching functionVSAvoidcontact erosion

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces electromechanical relays with solid-state electronic components including transistors, integrated circuits, and electronic switches. This substitution eliminates mechanical contacts and arcing, thereby preventing contact erosion while maintaining the switching control function for railroad track switches.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a second relay with high temperature coefficient resistor is used to protect against motor overload, then motor protection is achieved, but device complexity and cost increase considerably

Engineering Contradiction:

Improvemotor protectionVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple protection functions into a single integrated circuit that monitors motor current and integrates power consumption over time. This unified approach provides both overload protection and thermal protection without requiring separate relays and resistors, thereby reducing device complexity and cost while maintaining comprehensive motor protection.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of operation

If relay contacts are used for directional control, then switching direction is achieved, but unintended simultaneous closure can cause points to move opposite to intended direction

Engineering Contradiction:

Improvedirectional controlVSAvoiddirectional accuracy

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent replaces mechanical relay contacts with solid-state electronic switches controlled by logic circuits. The electronic control system uses binary logic states (0 or 1) to definitively control motor direction, eliminating the risk of simultaneous contact closure and ensuring that points move only in the intended direction without unintended reversals.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If frequent relay replacement is implemented to mitigate contact erosion, then contact reliability is maintained, but maintenance time and operational disruption increase

Engineering Contradiction:

Improvecontact reliabilityVSAvoidmaintenance time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces electromechanical relays with solid-state electronic components that have no wear-prone mechanical contacts. This eliminates contact erosion entirely, transforming the switching system from one requiring periodic maintenance to one that is maintenance-free for the lifetime of the electronic components, thereby eliminating maintenance time and operational disruption.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enhances the reliability and safety of railroad switch machines by preventing unintended track movements and protecting the motor from excessive current, reducing the need for frequent relay replacements and minimizing the risk of derailments.

Implementation Method 1

a motor (4) that is operatively coupled to the points (3) for selectively moving the points

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

a first relay (6) having one or more first normally open contacts (10) and one or more first normally closed contacts (8) provided in the normal connection path and a second relay (12) having one or more second normally open contacts (16) and one or more second normally closed contacts (14) provided in the reverse connection path

Methodology Applied

Scientific EffectElectromagnetic actuation: Electromagnet

Data Source

PatentUS8348202B2Railroad switch machine

Publication Date: 2013.01.08 ANSALDO STS USA INC

AI summary

A switch machine that includes a first relay having first normally open contacts and first normally closed contacts provided in the normal motor connection path and a second relay having second normally open contacts and second normally closed contacts provided in the reverse motor connection path. The normally open and closed contacts of each relay are associated in pairs and the first relays are structured such that each normally closed contact and the corresponding normally open contact cannot be simultaneously closed. Also, a method of protecting a motor of a switch machine that includes integrating a current being drawn by the motor and opening a motor circuit that includes the motor if the integrated current exceeds a threshold.