Contactor-Less Motor Starter for Voltage Sag Ride-Through
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Solution Overview
Problem
Traditional low voltage (LV) motor starters require a continuously energized contactor coil, making them susceptible to voltage sags and necessitating a perpetual power source, leading to energy inefficiencies and potential power interruptions.
Innovation Solution
A contactor-less motor starter design incorporating a Motor Circuit Protector (MCP) with a motorized mechanism, including a shaft, controller, and electric actuator, which allows the MCP to remain closed during power dips and self-reset upon power recovery, eliminating the need for a contactor and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contactor with normally energized coil is used to maintain circuit continuity, then the motor remains powered during operation, but the contactor trips and opens the circuit during voltage sags or power interruptions
Solution Approach 1:
The patent removes the contactor component entirely from the motor starter system. Instead of using a contactor with coil to maintain circuit continuity, the invention uses a motorized mechanism with electric actuator that can be controlled to close and hold the circuit without requiring continuous power to maintain the closed state, thereby eliminating vulnerability to voltage sags.
Solution Approach 2:
The motorized mechanism includes a self-holding feature where the electric actuator closes the circuit and maintains it in the closed position through its own mechanical holding mechanism, without requiring continuous external power signaling. The system serves itself by maintaining circuit continuity through mechanical means rather than continuous electrical energization.
2Ease of operation
If a contactor with normally energized coil is used to control the motor, then the motor can be started and stopped, but continuous power is required to keep the contactor operable
Solution Approach 1:
Instead of continuous power consumption to maintain the contactor coil energized, the system uses periodic action where the electric actuator is powered only momentarily to close the circuit, then the mechanical holding mechanism maintains the closed position without additional power. Power is consumed only during actuation events, not continuously during operation.
Solution Approach 2:
The motorized mechanism maintains circuit continuity through its own mechanical holding capability without requiring continuous external power input. The system serves itself by using the actuation energy to both close and hold the circuit, eliminating the need for continuous power consumption associated with contactor coil energization.
3Reliability
If a contactor is used to protect against overload and power loss, then the circuit can be opened under fault conditions, but manual intervention is required to reset the circuit after tripping
Solution Approach 1:
The motorized mechanism automatically resets the circuit by receiving reset signals from the controller after fault conditions are cleared. The electric actuator is powered to open the circuit during faults and can be automatically commanded to close the circuit again when protection conditions are satisfied, eliminating the need for manual intervention to reset the system.
Solution Approach 2:
The controller monitors protection conditions and provides feedback signals to the electric actuator. When overload or power loss conditions are detected, the controller signals the actuator to open the circuit. When conditions return to normal, the controller automatically sends a reset signal to close the circuit, creating a closed-loop feedback system that automates the protection and reset cycle.
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 design maintains power connectivity during voltage sags and self-resets after power recovery, reducing energy consumption and eliminating the need for manual intervention, while providing robust protection against overloads and ground faults.
Implementation Method 1
The motorized mechanism includes a shaft, a controller, and an electric actuator. The electric actuator actuates the shaft upon receiving the power
Implementation Method 2
The shaft is fixed to each of the one or more contacts, and actuates the contacts to the open or closed positions
Data Source
AI summary
A device for transmitting power includes a Motor Circuit Protector (MCP) and a motorized mechanism. The MCP includes contacts that electrically connect a power supply to a low voltage motor in a closed position, and disconnect the power supply from the low voltage motor in an open position. The motorized mechanism includes a shaft, a controller, and an electric actuator. The shaft is fixed to each of the one or more contacts, and actuates the contacts to the open and closed positions. The controller is electrically connected to the power supply, and processes operating instructions and transfers power to the electric actuator according to the operating instructions. The electric actuator actuates the shaft upon receiving the power, and the low voltage motor rotates when the power supply is connected thereto.