Disposer Motor Control Circuit for Startup and Excess Load Switching
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Solution Overview
Problem
Existing food waste disposer motors lack efficient control mechanisms to manage startup and excess load conditions, leading to potential motor overload and reduced performance.
Innovation Solution
A disposal assembly with a motor that includes a stator core, main and start windings, and a control circuit that manages power supply through switches. The control circuit closes switches during startup, detects voltage thresholds to ensure successful startup, and adjusts power supply based on voltage levels to handle excess load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical centrifugal switch is used to control main and auxiliary windings based on motor RPM, then the motor can be controlled during startup, but the control mechanism is complex and lacks efficiency in managing excess load conditions
Solution Approach 1:
The patent replaces the mechanical centrifugal switch with an electronic control circuit that uses voltage detection and electronic switching components. This substitution eliminates the mechanical moving parts and complex RPM-based mechanical control, providing a more reliable and efficient electronic control system that can also detect and respond to excess load conditions.
Solution Approach 2:
The control circuit incorporates voltage detection capabilities that monitor the motor's operational state and provide feedback to the switching mechanism. This feedback system allows the controller to detect voltage thresholds indicating successful startup or excess load conditions, and automatically adjust power supply accordingly, enhancing both reliability and load management.
2Reliability
If no voltage detection mechanism is implemented, then the control circuit is simple, but the motor cannot detect startup completion or excess load conditions
Solution Approach 1:
The control circuit incorporates voltage detection capabilities that monitor the motor's operational state and provide feedback to the switching mechanism. This feedback system allows the controller to detect voltage thresholds indicating successful startup or excess load conditions, and automatically adjust power supply accordingly, enhancing both reliability and load management.
3Reliability
If the start winding remains connected during normal operation, then the motor has continuous startup assistance, but the motor experiences overload and reduced performance
Solution Approach 1:
The control circuit dynamically adjusts the electrical configuration of the motor by switching the start winding connection status based on detected operational conditions. During startup, the start winding is connected to provide necessary starting torque; once the motor reaches operational speed (detected via voltage threshold), the control circuit disconnects the start winding to prevent overload and optimize performance. This dynamic switching resolves the contradiction between needing continuous startup assistance and maintaining optimal performance.
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 solution ensures reliable motor startup, prevents overload by dynamically adjusting power supply, and extends motor lifespan by effectively managing load conditions.
Implementation Method 1
The control circuit is configured to detect a voltage of at least one of the main winding and the start winding
Implementation Method 2
a capacitor coupled between the line terminal and the second switch
Implementation Method 3
The motor includes a stator core having a stator yoke and a plurality of teeth extending from the stator yoke toward a central opening
Data Source
AI summary
A disposal assembly includes a motor coupled to operate a grinding mechanism of a food waste disposer. A first switch is coupled to selectively inhibit the supply of power from a power source to a main winding of the motor, and a second switch is coupled to selectively inhibit the supply of power from the power source to a start winding of the motor. A control circuit is configured to close the first and second switches during an initial startup time period, detect a voltage of at least one of the windings, and open the second switch in response to detection of the voltage above a start voltage threshold value. The control circuit is also configured to subsequent to opening the second switch, close the second switch in response to detection of the voltage below a low voltage threshold value indicative of an excess load condition of the motor.