Relay Control Circuit Reducing Power Dissipation via Two-Stage Voltage
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Solution Overview
Problem
Conventional relay control methods dissipate excessive power due to the need for high voltages to both energize and maintain relays, which is inefficient, especially in compliance with energy efficiency standards like Energy Star guidelines and Department of Energy requirements.
Innovation Solution
A relay control circuit that uses a first voltage to initially energize the relay and then switches to a second, lower voltage to maintain it in an energized state, with a switch and diode configuration to manage the voltage inputs and a pulse generator or processor to control the relay's state, reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full rated pick-up voltage is applied continuously to the relay coil, then the relay remains reliably energized, but power dissipation is excessive
Solution Approach 1:
The patent applies periodic action by using a two-stage voltage scheme: full rated pick-up voltage is applied only during the brief period needed to energize the relay coil and close the switch, then a lower hold-up voltage is applied to maintain the energized state. This periodic switching between voltage levels reduces average power dissipation while ensuring reliable relay operation during the critical energization phase.
Solution Approach 2:
The patent implements dynamics by making the voltage applied to the relay coil time-dependent and state-dependent. The control circuit dynamically switches between two voltage levels based on the relay's energization state: full voltage during energization, reduced voltage during maintenance. This dynamic voltage adjustment optimizes both reliability and energy efficiency throughout the relay's operational cycle.
2Reliability
If full rated voltage is used to energize the relay, then the relay activates reliably, but power consumption is doubled compared to using only hold-up voltage
Solution Approach 1:
The patent applies preliminary action by providing the full rated pick-up voltage to the relay coil in advance, specifically during the energization phase, to ensure reliable activation. Once the relay is energized and the switch closes, the circuit transitions to using only the lower hold-up voltage. This preliminary high-voltage action ensures reliable relay activation while minimizing energy loss during the subsequent maintenance phase.
3Speed
If high voltage is applied to the relay coil, then the relay energizes quickly and reliably, but energy efficiency standards are not met
Solution Approach 1:
The patent resolves this contradiction by applying full rated voltage periodically only during the brief energization interval needed for quick and reliable relay activation, then switching to lower hold-up voltage for the remainder of the operational cycle. This periodic high-voltage application maintains fast energization response while achieving compliance with energy efficiency standards through reduced average power consumption.
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
This approach significantly reduces power dissipation by using the full rated pick-up voltage only for the necessary duration to energize the relay, allowing a lower hold-up voltage to maintain it, thereby utilizing less than half the power of conventional methods.
Implementation Method 1
a capacitor electrically coupled between the coil voltage input and ground
Implementation Method 2
a diode electrically coupled in series between the second input and the coil voltage input
Implementation Method 3
a first voltage capable of energizing the relay from a de-energized state
Data Source
AI summary
A relay control circuit for use with a relay having a coil voltage input. The relay control circuit includes a first input to receive a first voltage capable of energizing the relay, a second input to receive a second voltage, less than the first voltage, that is capable of maintaining the relay in an energized state, and means, responsive to a relay control signal having one of a first state and a second state, for switchably coupling the coil voltage input to the first input in response to the relay control signal having the first state, and for switchably coupling the coil voltage input to the second input in response to the relay control signal having the second state.