Motor Thermal Protection Using Capacitor-Based Cooling Time Tracking
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Solution Overview
Problem
Current motor thermal protection devices cannot accurately track and monitor accumulative heat accumulation in real time, leading to potential overheating accidents, as they cannot determine the remaining heat accumulation when the motor is powered on, relying on operator experience or prolonged cooling times.
Innovation Solution
A motor thermal protection device utilizing a capacitor timing circuit that calculates the power-off time by charging and discharging a capacitor, allowing for real-time monitoring of heat accumulation and automatic motor shutdown when overheating is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the motor is powered off for a long time to cool down completely, then the heat accumulation is reduced, but the productivity is decreased due to unnecessary waiting time
Solution Approach 1:
The system performs preliminary calculation of remaining heat accumulation when the motor is powered on, based on cooling time obtained from capacitor timing circuit. This allows the system to proactively determine safe operating conditions before actual operation begins, eliminating the need for conservative fixed waiting periods and enabling more efficient restart timing.
Solution Approach 2:
The system changes the parameter of heat accumulation assessment from a static, experience-based approach to a dynamic, calculated approach. By using the capacitor timing circuit to measure actual cooling time and calculating remaining heat accumulation based on this measured parameter, the system optimizes the balance between thermal safety and operational productivity.
2Ease of operation
If the accumulative heat accumulation is judged based on operator experience, then the operation is simple, but the measurement precision is low leading to unnecessary accidents
Solution Approach 1:
The system replaces the mechanical/cognitive method of operator experience-based judgment with an electronic measurement and calculation system. The capacitor timing circuit objectively measures cooling time, and the calculation unit precisely computes remaining heat accumulation, substituting subjective human judgment with objective electronic measurement while maintaining ease of operation through automatic functionality.
Solution Approach 2:
The system implements feedback by continuously monitoring motor operation status, measuring cooling time through the capacitor timing circuit, calculating remaining heat accumulation, and using this information to determine appropriate protective actions. This closed-loop feedback system replaces open-loop operator estimation with precise, data-driven decision-making.
3Device complexity
If the remaining heat accumulation is not determined when motor is powered on, then the device complexity is low, but the reliability is reduced due to inability to accurately track heat accumulation
Solution Approach 1:
The system performs preliminary determination of remaining heat accumulation at the moment the motor is powered on, using the capacitor timing circuit to measure cooling time and calculate the current thermal state. This preliminary assessment provides a reliable baseline for subsequent heat accumulation tracking without requiring complex continuous monitoring from scratch.
Solution Approach 2:
The capacitor timing circuit serves as an intermediary element that indirectly measures the thermal state of the motor by timing the cooling period. Instead of directly measuring temperature, the circuit uses electrical timing to represent thermal conditions, providing a simple yet reliable method to determine remaining heat accumulation with minimal device complexity.
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 real-time tracking of heat accumulation, preventing motor and equipment damage by automatically powering off the motor when overheating conditions are met, ensuring safer operation.
Implementation Method 1
A motor thermal protection device utilizing a capacitor timing circuit that calculates the power-off time by charging and discharging a capacitor
Data Source
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AI summary
It is disclosed a motor thermal protection device (100) and operation method thereof. The motor thermal protection device utilizes a power supply of a motor (Vin) for power supplying and comprises: a capacitor timing circuit (101), configured to time after the motor is powered off; a power-off time determining unit (102), configured to perform a reading operation of reading an output voltage of the capacitor timing circuit after the motor is powered on, and determine a power-off time from when the motor is powered off to when the motor is powered on according to the output voltage; and a heat accumulation calculating unit (103), configured to calculate a remaining heat accumulation (THS(0)) when the motor is powered on according to the power-off time and a heat accumulation when the motor is powered off.