Washing Machine Drum Blockage Detection Using Motor Current Monitoring
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Solution Overview
Problem
Laundry care appliances often experience drum jams due to slippage caused by uneven laundry distribution, leading to drive belt wear and tear, complex repairs, and high maintenance costs.
Innovation Solution
A method to detect drum jams by monitoring motor torque-forming current, torque, and phase current, calculating a parameter set, and adjusting motor control to prevent further damage, which includes reversing the motor direction or reducing speed to release the jam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor continues to operate after drum jam detection, then the motor maintains its driving function, but the drive belt wears through and tears causing complex repairs
Solution Approach 1:
The control device interrupts motor operation before the drive belt suffers irreversible damage. By detecting drum jam conditions through current monitoring and prematurely stopping the motor, the system prevents belt wear-through and tear, eliminating the need for complex repairs and maintaining drive belt durability.
2Reliability
If the motor speed is reduced to prevent belt wear, then the drive belt durability is improved, but the washing productivity decreases
Solution Approach 1:
The system periodically monitors motor current to detect drum jam conditions and intermittently interrupts motor operation only when jams are detected. During normal operation, the motor runs at full speed maintaining washing productivity. This periodic detection and selective interruption prevents belt wear while minimizing impact on overall productivity.
Solution Approach 2:
The system allows the motor to operate at full speed through normal washing cycles to maintain productivity, but rapidly interrupts operation when drum jam conditions are detected. This rushing through of normal operation at high speed while quickly stopping when problems arise prevents belt damage without significantly reducing overall productivity.
3Reliability
If current monitoring is continuously performed to detect drum jams early, then the drive belt durability is improved, but the energy consumption increases
Solution Approach 1:
The control device continuously monitors motor current as feedback to detect changes indicating drum jam conditions. This real-time feedback enables early detection of jams before belt damage occurs. The monitoring uses the existing motor current signals already present in the control system, so the additional energy consumption is minimal while significantly improving drive belt durability.
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 method allows for early detection and prevention of drive belt wear, reducing repair costs and downtime by enabling quick response to drum blockages and preventing belt tears.
Implementation Method 1
a motor (13) with a motor pinion (15), a drive belt (17) that mechanically couples the motor to the drum via the motor pinion
Implementation Method 2
a drive belt (17) that mechanically couples the motor to the drum via the motor pinion (15), the motor pinion (15), together with the drive belt (17), transfers torque from the motor (13) to the drum (7)
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The present invention relates to a method for detecting a drum blockage in a laundry care appliance (3), the laundry care appliance (3) comprising a rotatable drum (7) which can be driven by a motor (13) via a drive belt (17), wherein the method comprises the steps: a) determining at least one or more of the following values of the motor (13): torque-generating current, torque, phase current and/or envelope of the phase current, b) calculating a parameter set from the values determined in step a), c) checking the parameter set for a signal characteristic of a drum blockage, d) adjusting the control of the motor (13) when a characteristic signal has been detected. The present invention further relates to a laundry care appliance (3) which is designed and configured to carry out the method according to the invention.