Household Appliance Drive Motor Power Limiting Under Low Mains Voltage
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Solution Overview
Problem
Existing drive devices for laundry drums in washing machines require significant material and space due to the need to withstand increased operating temperatures caused by varying mains voltage amplitudes, leading to higher manufacturing costs and less compact designs.
Innovation Solution
A control device that limits electrical power to the drive motor based on the amplitude of the mains voltage, maintaining the operating temperature within a predetermined limit, thereby reducing material requirements and allowing for a more compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive motor is designed to withstand increased operating temperatures caused by varying mains voltage amplitudes, then the motor can operate reliably under all voltage conditions, but the material consumption and installation space increase
Solution Approach 1:
The patent applies dynamics by making the electrical power delivery to the drive motor adjustable rather than fixed. The control device dynamically adapts the power delivery based on detected mains voltage amplitude, allowing the motor to operate reliably across varying voltage conditions without requiring design for maximum extreme conditions. This dynamic adaptation resolves the contradiction by enabling reliable operation without over-engineering for worst-case scenarios.
Solution Approach 2:
The patent changes the operational parameters of the drive motor based on detected mains voltage conditions. When the mains voltage amplitude falls below the limit value, the control device limits the electrical power delivered to the motor, thereby controlling the motor current amplitude and operating temperature. This parameter adjustment allows the motor to be designed with reduced material consumption while maintaining reliability through adaptive operation.
2Reliability
If the drive motor is designed to withstand increased operating temperatures caused by varying mains voltage amplitudes, then the motor can operate reliably under all voltage conditions, but the installation space increases
Solution Approach 1:
The control device dynamically adjusts the electrical power delivered to the drive motor based on detected mains voltage amplitude. This dynamic operation allows the motor to maintain reliable performance across varying voltage conditions without requiring the physical dimensions and installation space necessary for a motor designed to withstand maximum operating temperatures under all conditions.
3Temperature
If the electrical power is limited when mains voltage amplitude is below the limit value, then the operating temperature of the drive motor is controlled, but the speed of the laundry drum may decrease
Solution Approach 1:
The patent converts the potentially harmful effect of limited electrical power (which could reduce motor speed and drum spin speed) into a beneficial outcome by establishing that the mains voltage amplitude detection and power limiting actually prevents overheating. The speed reduction that would normally occur is reframed as a controlled operational parameter that ensures reliable motor operation within safe temperature boundaries, transforming a potential disadvantage into a protective mechanism.
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 results in a more cost-effective and space-efficient drive motor that maintains performance while reducing material usage and operating temperatures, even during spin cycles with varying voltage conditions.
Implementation Method 1
The control device can detect a measured variable that is correlated with the amplitude of the mains voltage and can use the measured variable to identify whether the amplitude of the mains voltage is below a predetermined limit value
Implementation Method 2
In such a case, the control device limits the electrical power to a value greater than zero
Implementation Method 3
If the amperage of the motor current increases, the operating temperature of the drive motor also increases
Data Source
AI summary
The invention relates to a drive device (2) for driving a component (3) of a household appliance (1), comprising an electric drive motor (4) and a control device (10) for setting an electric power output delivered to the drive motor (4), wherein the control device (10) is designed to detect a measurement variable US, which is correlated with an amplitude of a mains voltage UN that can be supplied to the drive device (2), and to identify on the basis of said measurement variable US whether the amplitude of the mains voltage UN is below a predefined threshold value and, if this is the case, to limit the electric power output to a value greater than zero. Using such a procedure, a limit in terms of the current intensity of the motor current I1, l2, I3 and also in terms of an operating temperature of the drive motor are set. This is advantageous with respect to material savings during the production of the drive motor (4). At lower operating temperatures, less material via which the heat has to be evacuated is correspondingly required for the drive motor (4). As a result, savings can be achieved in terms of the production costs of the drive motor (4) and the valuable installation space in the household appliance (1).