Relay Contact Weld Detection Using Spanner Voltage Measurement
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Solution Overview
Problem
Existing relay systems struggle to detect single welded double break contacts, which can lead to catastrophic failures and damage to industrial equipment due to undetected short circuits.
Innovation Solution
A method and system for detecting single welded relay contacts by measuring voltage between the spanner of a first relay and the input side of a second relay, determining the presence of a weld based on measured voltage thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional relay contact monitoring methods are used, then the system structure remains simple, but the ability to detect single welded contacts is insufficient leading to undetected short circuits
Solution Approach 1:
The patent introduces a spanner terminal as an intermediary measurement point that provides access to the contact state without requiring direct contact with the welded contact. By measuring voltage between the spanner and input terminal, the system can detect welded contacts through the electrical state reflected at the spanner, which is electrically coupled to the contact assembly
Solution Approach 2:
The patent replaces mechanical detection methods (such as physical inspection or mechanical test mechanisms) with electrical voltage measurement. The controller measures voltage signals between the spanner and input terminal to detect the welded state, substituting electrical sensing for mechanical detection approaches
2Reliability
If voltage measurement between spanner and input side is performed, then single welded contacts can be detected early, but additional measurement points and control logic are required
Solution Approach 1:
The spanner terminal serves multiple functions: it acts as a connection terminal for the contact assembly, provides a measurement reference point for weld detection, and enables electrical access to the contact state. This multi-functionality reduces the need for separate dedicated detection components
3Reliability
If continuous monitoring is implemented to ensure detection accuracy, then reliability improves, but energy consumption and system complexity increase
Solution Approach 1:
The patent implements periodic monitoring by having the controller measure voltage between the spanner and input terminal at specified intervals or at predetermined moments in the relay operation cycle. This periodic measurement approach provides sufficient detection capability while minimizing continuous energy consumption compared to constant monitoring
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 early detection of welded relay contacts, preventing potential short circuits and equipment damage by allowing for proactive system shutdown or disconnection.
Implementation Method 1
measuring a voltage between a spanner of a first relay of a plurality of relays and an input side of a second relay of the plurality of relays
Data Source
AI summary
A system includes a relay system and a controller. The relay system includes a plurality of relays, each having a first contact on an input side of the respective relay, the input side coupled to a power source, a second contact on a load side of the respective relay coupled to a load, and a spanner configured to close the first and second contacts of the respective relay when activated by a close signal. The load sides of each of the respective relays are coupled through their respective loads. The controller is configured to measure a voltage between a spanner of a first relay and an input side of a second relay. Based on the voltage between the spanner of the first relay and the input side of the second relay, the controller determines whether an electrical weld of one of the contacts of the first relay exists.