Dual Temperature Switch Circuit for Compressor Overheat Lockout

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Solution Overview

Problem

Conventional compressors prone to overheating and repeated on-off cycles due to dust accumulation, leading to potential damage from thermal stress.

Innovation Solution

A dual temperature sensing system comprising an automatic and a passive temperature sensing switch that disconnects the power supply from the processor module when overheating is detected, preventing repeated on-off cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional automatic temperature sensing switch with a bimetallic strip is used, then the compressor can automatically restart after cooling down, but the compressor suffers from repeated on-off cycles that increase damage risk

Engineering Contradiction:

Improveautomatic restart capabilityVSAvoidcompressor durability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The protection system is divided into two independent temperature sensing switches: an automatic temperature sensing switch (first switch) and a passive temperature sensing switch (second switch). The first switch handles automatic restart when temperature drops, while the second switch prevents automatic restart when temperature was excessively high, thereby segmenting the protection functions to eliminate harmful repeated cycling while preserving beneficial automatic restart capability.

Inventive Principle:

Principle #1Segmentation

2Extent of automation

If the compressor is allowed to automatically switch on and off due to overheating and cooling, then the temperature sensitive strip can reset the circuit, but the repeated thermal cycling increases the chance of compressor damage

Engineering Contradiction:

Improveautomatic circuit resetVSAvoidthermal stress damage

Core Design Contradiction:

Extent of automationVSObject-affected harmful factors

Solution Approach 1:

The passive temperature sensing switch is positioned to detect high temperature conditions and sever the circuit connection before the compressor can undergo repeated thermal cycling. This preliminary protective action prevents the harmful thermal stress from occurring in the first place, rather than merely responding after damage has begun to accumulate from repeated on-off cycles.

Inventive Principle:

Principle #9Preliminary anti-action

3Device complexity

If only a single automatic temperature sensing switch is used, then the device complexity is low, but the protection against repeated thermal cycling is insufficient

Engineering Contradiction:

Improvenumber of temperature sensing switchesVSAvoidprotection effectiveness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The protection function is segmented into two specialized switches: the first automatic temperature sensing switch monitors for safe restart conditions, while the second passive temperature sensing switch specifically monitors for dangerous high-temperature conditions that should prevent restart. This functional segmentation provides comprehensive protection without requiring complex control logic within a single device.

Inventive Principle:

Principle #1Segmentation

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

Prevents compressor damage by maintaining it in an off state during overheating, extending its lifespan by avoiding repeated thermal cycling.

Implementation Method 1

When the compressor M overheats, the temperature sensitive strip 165 within the compressor M absorbs heat and curls

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The rectifier module is configured to electrically connect to a power supply for rectifying a voltage supplied by the power supply into a voltage signal

Methodology Applied

Scientific EffectRectification:

Data Source

PatentUS12492704B1Compressor temperature protection module and protection system thereof

Publication Date: 2025.12.09 NEW WIDETECH IND

AI summary

A compressor temperature protection module and protection system thereof, wherein the module includes an automatic temperature sensing switch that senses a first temperature in a compressor and a passive temperature sensing switch that senses a second temperature on the compressor. When the passive temperature sensing switch senses the second temperature is greater than a second default value, the passive temperature sensing switch automatically severs a connection between a direct current (DC) power source and a processor module. When the automatic temperature sensing switch senses the first temperature within the compressor is greater than a first default value, the automatic temperature sensing switch automatically severs a connection between the compressor and a power supply. Afterwards, when the first temperature becomes less than the first default value, the automatic temperature sensing switch electrically connects to the control switch of the control module.