Configurable Motor Overload Detection via Adjustable Trip Thresholds

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Solution Overview

Problem

Thermal protectors in motor overload detection systems are not settable to allow various trip temperatures, limiting their application in different motor implementations, as they only protect against a fixed overload criterion.

Innovation Solution

A system and method incorporating a contactor, current sensing relay, and thermal overload solution that allows configurable trip values for both current and temperature thresholds, enabling protection against locked rotor situations and single phasing, using a sensing device and relays to control power delivery to the motor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermal protectors with fixed trip temperatures are used, then the motor is protected against thermal overload, but the system lacks adaptability to various trip temperature requirements

Engineering Contradiction:
Improvemotor protectionVSAvoidtrip temperature configurability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces fixed thermal protectors with adjustable thermal protectors that allow dynamic configuration of trip temperature values. This enables the same motor protection system to adapt to different thermal overload criteria across various applications while maintaining reliable protection.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the fixed parameter of thermal protectors into adjustable parameters. By allowing users to set different trip temperature values, the system can accommodate different thermal overload conditions without requiring different hardware components.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If fixed trip value protectors are used, then the motor is protected against current overload, but the system cannot be configured for different trip values in various applications

Engineering Contradiction:
Improvecurrent overload protectionVSAvoidtrip value configurability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces adjustable circuit sensing relays that replace fixed trip value protectors. These relays allow dynamic configuration of trip current values, enabling the motor protection system to adapt to different current overload criteria while maintaining reliable protection.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention transforms the fixed trip value parameter into an adjustable parameter. Users can configure different trip current values to match specific application requirements, making the protection system versatile across different motor implementations.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If thermal protectors alone are used, then thermal overload is detected, but the system cannot detect current-based overload conditions

Engineering Contradiction:
Improvethermal overload detectionVSAvoiddetection method flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent combines thermal protectors with circuit sensing relays to create a multi-functional protection system. This unified system can detect both thermal overload conditions (via temperature sensors) and current-based overload conditions (via current monitoring), providing comprehensive motor protection.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges thermal protection and current protection functions into a single integrated system. The control circuit receives inputs from both thermal protectors and circuit sensing relays, enabling coordinated detection and response to different types of overload conditions.

Inventive Principle:
Principle #5Merging (Combining)

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 adaptable thermal and current-based overload detection, protecting motors against various overload conditions by setting threshold values in advance, thus enhancing protection across different applications.

Implementation Method 1

a sensing device, a first circuit sensing relay and a second circuit sensing relay, the first circuit sensing relay being employed on the first lead line

Methodology Applied
Scientific EffectThermal sensing: Thermal Radiation

Implementation Method 2

the first circuit sensing relay is configured to detect a target current of the motor and trigger a first contact of the contactor

Methodology Applied
Scientific EffectElectrical current sensing: Electrical Resistance

Data Source

PatentEP3202004B1Compressor motor overload detection
Publication Date: 2022.03.23 CARRIER CORP
  • EP3202004B1 patent drawingFigure 1
  • EP3202004B1 patent drawingFigure 2
  • EP3202004B1 patent drawingFigure 3

AI summary

A system for detecting overloads of a motor comprises a motor configured to receive power via a lead line, a first sensing device configured to sense a temperature of a motor, and a second sensing device electrically coupled to the motor and configured to detect a target current of the motor and trigger a contact of the lead line associated with second sensing device when the target current equals or exceeds a trip value.