Motor Winding Resistance Measurement for Instant Temperature Detection
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Solution Overview
Problem
Existing methods for determining the temperature of electric motor windings, such as using temperature sensors, suffer from latency issues and increase complexity and fault susceptibility, limiting the operational capacity of electric motors.
Innovation Solution
A method that determines the temperature of electric motor windings by measuring the electrical resistance, which is directly related to temperature, using a current sensing resistor and tabulated pairs of resistance/temperature values, eliminating the need for separate temperature sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are used to determine motor winding temperature, then temperature monitoring is achieved, but latency time increases and operational capacity is reduced
Solution Approach 1:
The patent replaces mechanical/physical temperature sensors with an electrical measurement method. Instead of using thermal sensors that physically contact or near the motor winding to detect temperature, the invention uses electrical resistance measurements of the winding itself. Since resistance changes with temperature according to the temperature coefficient of the winding material, this electrical substitution eliminates the thermal latency inherent in sensor-based methods while providing instantaneous temperature indication through resistance measurements.
Solution Approach 2:
The patent introduces electrical resistance as an intermediary parameter to indirectly determine temperature. Rather than measuring temperature directly with sensors, the method measures the winding's electrical resistance, which serves as a mediator that reflects temperature changes. This intermediary approach allows temperature determination through electrical properties that change predictably with temperature, avoiding the latency of thermal sensor response.
2Measurement precision
If temperature sensors are installed in the motor, then temperature detection capability is provided, but device complexity and fault susceptibility increase
Solution Approach 1:
The patent extracts the temperature sensing function from separate physical temperature sensors and integrates it into the motor winding itself. By utilizing the inherent electrical resistance property of the winding that changes with temperature, the invention removes the need for additional sensor components. This extraction principle eliminates the complexity and fault susceptibility associated with separate temperature sensor systems while maintaining temperature detection capability.
Solution Approach 2:
The patent makes the motor winding multi-functional by having it serve both its primary function of electrical energy conversion and the secondary function of temperature indication. The winding's electrical resistance, which is essential for its operation, also provides temperature information when measured. This universality eliminates the need for dedicated temperature sensing components, reducing overall system complexity while achieving temperature monitoring.
3Reliability
If temperature sensors are used for motor temperature monitoring, then overheating protection is achieved, but operational capacity must be reduced to account for latency
Solution Approach 1:
The patent enables preliminary temperature assessment by measuring the winding's electrical resistance at any moment, which instantly reflects the current temperature state. This preliminary information allows the control system to adjust operational parameters proactively before critical temperature limits are approached, eliminating the need to operate with capacity reserves that were previously required to account for sensor latency. The instantaneous resistance measurement provides advance warning capability.
Solution Approach 2:
By substituting thermal sensor-based temperature measurement with electrical resistance measurement, the invention eliminates the inherent thermal latency that forced operational capacity reductions. The electrical resistance method provides instantaneous temperature indication, allowing the motor to operate at full capacity while maintaining reliable overheating protection through real-time temperature monitoring via resistance measurements.
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
This approach allows for precise and instantaneous temperature determination, enabling energy management that prevents overheating without the latency and complexity issues of traditional methods, allowing electric motors to operate closer to their capacity limits.
Implementation Method 1
Due to the distinct temperature dependency, the electrical resistance is a suitable measure for this purpose, which moreover is metrologically easily accessible. In particular, the electrical resistance changes so to say instantly with the temperature of the motor winding
Implementation Method 2
determining the electrical resistance of the motor winding from the quotient of voltage to amperage
Data Source
AI summary
A method of determining the temperature of a motor winding of an electric motor, in particular of an electric door drive motor includes determining the electric resistance of the motor winding as a measure for the temperature. The method also includes the steps of providing the electric motor with at least one current sensing resistor and applying an electric voltage to the motor winding.