Terminal Blocks With Integral Relays and Testable Contacts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Safety instrumented systems with safety relays require high diagnostic coverage and fault tolerance, but existing terminal blocks lack efficient methods for testing the operability of relay contacts to ensure they can break electrical paths as intended, particularly in scenarios where contacts may weld or fail to open.
Innovation Solution
The development of terminal blocks with integral relays and independently testable contacts, including test points that allow users to verify the functionality of relay contacts by measuring resistance and voltage across them, ensuring they can properly break or maintain electrical paths during proof tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple force-guided relays with mechanically linked relay contacts are used to provide fault tolerance, then the reliability of the safety relay is improved, but the ability to independently test individual relay contacts deteriorates
Solution Approach 1:
The patent divides the mechanically linked relay contact system into independently testable segments by providing separate test points for each relay contact. This allows individual testing of each contact while maintaining the mechanical linkage for fault tolerance during operation.
Solution Approach 2:
The patent introduces test points as intermediary access points between the mechanically linked relay contacts and the testing device. These test points enable independent measurement and testing of each contact without disrupting the mechanical linkage that provides fault tolerance.
2Reliability
If relay contacts are mechanically linked to move together, then the diagnostic coverage is improved through coordinated failure detection, but the ability to verify individual contact operability deteriorates
Solution Approach 1:
The patent segments the measurement capability by providing separate test points for each relay contact, enabling individual measurement of each contact's resistance and voltage while the contacts remain mechanically linked for coordinated operation.
Solution Approach 2:
The patent enables preliminary testing of individual relay contacts before system operation through the provision of accessible test points. This allows verification of contact integrity and operability prior to energizing the safety relay system.
3Reliability
If proof testing is performed on mechanically linked relay contacts, then the system-level functionality is verified, but the detection of welded or stuck individual contacts deteriorates
Solution Approach 1:
The patent segments the testing capability by providing individual test points for each relay contact, enabling independent measurement of each contact's electrical properties. This segmentation allows detection of welded or stuck contacts at the individual component level while maintaining system-level testing capability.
Solution Approach 2:
The patent replaces purely mechanical testing methods with electrical measurement methods through the use of test points that allow resistance and voltage measurements. This substitution enables more sensitive detection of welded or stuck contacts through electrical property measurement rather than relying solely on mechanical movement observation.
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
Enables reliable testing of relay contacts to ensure they are operational and not welded, thereby enhancing the fault tolerance and diagnostic coverage of safety instrumented systems by allowing users to verify the integrity of the electrical paths in both de-energize-to-fail and energize-to-actuate circuits.
Implementation Method 1
relay contacts that move together when one or more relay coils are energized or de-energized
Implementation Method 2
relay contacts that move together when one or more relay coils are energized or de-energized
Implementation Method 3
measure the resistance across the contacts (e.g., the voltage should be zero) and then actuate the relays and measure the voltage between the test point and the first and/or second relay contacts
Data Source
AI summary
An example apparatus includes a terminal block couplable to an electronics cabinet or mounting rail. The terminal block defines a first receptacle to receive a first circuit and a second receptacle to receive a second circuit. The terminal block includes an integral relay. The integral relay includes a first contact and a second contact. The first and second contacts are externally accessible relative to the terminal block. The integral relay further includes a first switch and a second switch. The first and second switches are electrically coupled between the first and second contacts. The first and second switches are respectively movable between corresponding open and closed positions. The first and second switches are independently testable to verify the respective operability of the first switch and the second switch.