Compressor Fault Diagnostic Apparatus for Reverse Rotation Detection

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Solution Overview

Problem

Constant-speed compressors are prone to reverse rotation during instantaneous power outages, leading to abnormal pressure formation and reduced reliability, with existing solutions failing to address this issue effectively.

Innovation Solution

A compressor fault diagnostic apparatus that includes a current sensing unit to monitor motor current, a fault diagnostic unit to determine reverse rotation, and a cut-off unit to prevent power application, thereby preventing reverse rotation and improving compressor reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If constant-speed compressor is driven at fixed frequency, then compressor operation is simple and reliable, but reverse rotation occurs during power outage causing damage

Engineering Contradiction:

Improvecompressor operation reliabilityVSAvoidreverse rotation damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The diagnostic apparatus performs preliminary detection of reverse rotation conditions by monitoring current characteristics before actual reverse rotation damage occurs. The system identifies abnormal current patterns that precede reverse rotation and triggers preventive power cutoff, acting in advance to prevent the harmful effect.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors motor current and provides feedback to the control unit. When abnormal current characteristics indicating reverse rotation are detected, the feedback loop triggers the cut-off unit to remove power, creating a closed-loop control system that prevents reverse rotation damage through real-time monitoring and response.

Inventive Principle:

Principle #23Feedback

2Reliability

If power is continuously monitored to detect reverse rotation, then reverse rotation can be prevented, but system complexity increases

Engineering Contradiction:

Improvereverse rotation preventionVSAvoiddiagnostic apparatus complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system replaces complex mechanical reverse rotation prevention mechanisms with an electrical diagnostic approach. By monitoring electrical current characteristics and using electronic control to cutoff power, the system achieves reverse rotation prevention without adding mechanical complexity to the compressor mechanism.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The diagnostic apparatus utilizes the existing motor current that flows during normal operation for diagnostic purposes. The same current that powers the motor also provides the diagnostic information needed to detect reverse rotation conditions, eliminating the need for separate sensing systems and reducing overall system complexity.

Inventive Principle:

Principle #25Self-service

3Reliability

If compressor operation is interrupted frequently for fault checking, then reverse rotation is detected, but operation efficiency deteriorates

Engineering Contradiction:

Improvefault detection accuracyVSAvoidcompressor operation efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The diagnostic apparatus enables continuous monitoring of motor current without interrupting compressor operation. By analyzing current characteristics during normal operation, the system maintains continuous useful action of the compressor while simultaneously detecting reverse rotation conditions, avoiding efficiency deterioration from frequent interruptions.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The system performs partial diagnostic action by monitoring only specific current characteristics that indicate reverse rotation, rather than performing comprehensive fault checks. This selective monitoring approach detects reverse rotation conditions while minimizing interference with normal compressor operation and maintaining high operational efficiency.

Inventive Principle:

Principle #16Partial or excessive action

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 apparatus effectively prevents compressor reverse rotation during power outages, enhancing operational reliability and allowing for continuous operation without efficiency deterioration, while also diagnosing refrigerant leakage and condenser faults, and transmitting fault information for prompt user action.

Implementation Method 1

a current sensing unit for sensing a current value flowing through a motor

Methodology Applied

Scientific EffectElectrical measurement: Ohm's Law

Data Source

PatentUS11754073B2Compressor fault diagnostic apparatus and system

Publication Date: 2023.09.12 LG ELECTRONICS INC

AI summary

A compressor fault diagnostic apparatus including a current sensing unit to sense a current flowing through a motor of the compressor, a fault diagnostic unit to determine whether or not the motor performs a reverse rotation based on the current flowing through the motor, and a cut-off unit to remove power based on a determination of the fault diagnostic unit.