Multipole Relay Pole Deterioration Detection Using Shunt Voltage
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Solution Overview
Problem
Existing relay state determination devices struggle to accurately assess deterioration in multipole relays, as they cannot individually determine the condition of each pole.
Innovation Solution
A relay state determination device that includes a primary-side switch, operation coil, shunt resistor, and diode, with a voltage value acquisition unit, voltage value difference calculation unit, and state determination unit, which measures and calculates voltage differences across the shunt resistor and secondary-side contacts to determine relay deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If maximum current value measurement method is used, then relay deterioration can be determined, but deterioration of each individual pole in multipole relay cannot be determined
Solution Approach 1:
The patent divides the measurement process into separate segments for each pole of the multipole relay. By measuring the voltage across the shunt resistor individually for each pole's operation coil, the system can determine deterioration of each individual pole separately, rather than measuring the combined current of all poles together.
2Measurement precision
If voltage measurement across shunt resistor is performed, then individual pole deterioration can be detected, but device complexity increases
Solution Approach 1:
The patent introduces a shunt resistor as an intermediary component connected in series with each operation coil. This shunt resistor enables voltage measurement that reflects the current flowing through each pole's operation coil, allowing individual pole deterioration detection without requiring direct current measurement or complex measurement circuits.
3Measurement precision
If diode is added in parallel to operation coil and shunt resistor, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The patent addresses the harmful effect of counter electromotive force (which can cause voltage spikes and measurement errors) by converting it into a beneficial measurement opportunity. The diode provides a discharge path for the counter EMF, and the voltage across the shunt resistor during this discharge phase is used to determine relay deterioration, turning a potentially harmful electrical phenomenon into a useful measurement signal.
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 accurate determination of each individual pole's deterioration in a multipole relay by calculating and comparing voltage value differences, allowing for timely maintenance and preventing operational failures.
Implementation Method 1
an armature that opens and closes at least a pair of secondary-side contacts in response to on and off of the primary-side switch, the armature being configured to be displaced relative to the operation coil by an electromagnetic force generated by the operation coil
Implementation Method 2
a diode connected in parallel to a series connection of the operation coil and the shunt resistor in a direction in which current due to a counter electromotive force of the operation coil flows to the shunt resistor when the primary-side switch is turned off
Data Source
AI summary
A relay state determination device according to the present invention includes: a voltage value acquisition unit that measures every moment a detected voltage detected from two ends of a shunt resistor; a voltage value difference calculation unit that calculates a voltage value difference between a first voltage value of when the detected voltage becomes minimum by an armature starting displacement after a primary-side switch is turned off and a second voltage value of when secondary-side contacts are opened; and a state determination unit that determines that a relay has deteriorated when the voltage value difference falls below a predetermined threshold value.