Software Thrust Bearing Failure Detection in Motor Driven Compressors

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Solution Overview

Problem

Conventional motor driven compressors (MDCs) face challenges in detecting thrust bearing failures, as surface-mounted thermal switches can shift and become non-operational over time, leading to increased surface temperatures and potential shutdowns.

Innovation Solution

A software-based system with sensing elements, a servo control element, and a timing element, controlled by a processor, which monitors rotational speeds, shuts down and restarts the MDC based on predicted minimum speeds, tracks successful restarts, and ceases operations after a predefined number of consecutive failures, ensuring continuous functionality without physical component shift.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If surface mounted thermal switches are used to detect thrust bearing failures, then failure detection capability is provided, but the thermal switches can shift in position and cease to be fully operational over time

Engineering Contradiction:

Improvefailure detection capabilityVSAvoidposition stability of thermal switch

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent replaces the mechanical thermal switch system with a software-based detection system that uses sensor data processing and algorithmic analysis to detect thrust bearing failures. The controller executes software routines that monitor compressor operation parameters, calculate thrust bearing temperature based on operational data, and detect failures without physical thermal switches, thereby eliminating the position stability issue inherent in mechanical thermal switch systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If software-based detection is implemented, then reliability of failure detection is improved without physical component shift, but device complexity increases due to additional sensing elements and control logic

Engineering Contradiction:

Improvefailure detection reliabilityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The controller in the patent performs multiple functions: it controls compressor operation, processes sensor data, calculates thrust bearing temperature, detects failures, and executes protective shutdown routines. By making the controller multi-functional, the patent avoids adding separate dedicated hardware for each function, thereby reducing overall system complexity while maintaining high reliability through integrated software-based detection and control.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The software-based detection system uses existing sensor data from the compressor's normal operation to detect thrust bearing failures. The system self-monitors its own operational parameters and uses this data to calculate temperatures and detect anomalies without requiring additional independent measurement systems, thereby reducing complexity while improving reliability.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS10830245B2Software-based detection of thrust bearing failures for use with a motor driven compressor

Publication Date: 2020.11.10 HAMILTON SUNDSTRAND CORP

AI summary

A system for controlling a motor driven compressor (MDC) is provided. The system includes a sensing element and a controller coupled to the sensing element. The controller is configured to determine whether an actual speed of the MDC sensed by the sensing element is below a predicted minimum speed, shut down and then restart the MDC and detect if the restart of the MDC is successful.