AC Motor Spin-Drying Control to Avoid Washer Resonance
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Solution Overview
Problem
Washing machines with non-control type motors experience resonance phenomena during spin-drying operations, leading to vibrations and noise, and lack precise control over rotary speed, making it difficult to maintain optimal operating conditions.
Innovation Solution
Incorporating an alternating current (AC) motor with a clutch assembly that selectively transfers torque to a rotating tub and pulsator, a speed detector to monitor rotary speed, and a controller that adjusts the motor's operation based on predetermined target speeds and error tolerances, gradually increasing torque and controlling phase angles of AC power to minimize resonance and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a non-control type motor is used to reduce cost, then the device complexity is reduced, but the manufacturing precision and control accuracy deteriorate due to inability to precisely control rotary speed
Solution Approach 1:
The patent introduces a speed detector that provides feedback on the actual rotary speed of the motor to the controller. This feedback mechanism enables the controller to adjust the motor operation dynamically, achieving precise speed control without requiring a complex control-type motor. The feedback loop allows the system to compensate for speed deviations and maintain accurate control.
Solution Approach 2:
The patent implements periodic operation of the motor during spin-drying, where the motor is repeatedly started and stopped in controlled cycles. This periodic action allows the system to build up speed gradually and maintain it within acceptable ranges, preventing resonance phenomena while using a simpler non-control type motor.
2Productivity
If the motor operates continuously at high speed to improve productivity, then the spin-drying efficiency is improved, but harmful factors increase due to resonance phenomenon and violent vibration
Solution Approach 1:
The patent employs periodic start-stop operation of the motor during spin-drying cycles. By intermittently operating the motor rather than running it continuously, the system achieves spin-drying effectiveness while avoiding sustained resonance conditions. The periodic operation allows the tub to pass through critical resonance speeds quickly and maintain operation outside resonant frequency ranges.
Solution Approach 2:
The patent makes the motor operation dynamic by continuously adjusting its operation based on real-time speed detection. The controller dynamically modulates the motor's on/off timing to maintain optimal spin-drying performance while avoiding resonance zones, transforming the static continuous operation into a dynamic adaptive process.
3Ease of manufacture
If the motor is operated with simple turn-on and turn-off control to reduce device complexity, then the ease of manufacture is improved, but the stability deteriorates due to inability to deviate from resonance speed
Solution Approach 1:
The patent introduces a speed detector that provides real-time feedback on motor speed to the controller. This feedback enables the simple non-control type motor to operate stably by allowing the controller to adjust operation timing based on actual speed conditions, preventing resonance and maintaining stable spin-drying performance.
Solution Approach 2:
The patent replaces complex mechanical speed control mechanisms with an electronic control system that uses electrical timing and phase angle control. This substitution maintains the simplicity of the motor itself while achieving stable operation through electronic intervention rather than mechanical complexity.
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
The solution effectively reduces resonance and noise, allows for precise control of rotary speed, and detects potential failures in the speed detection system, enhancing the operational stability and efficiency of the washing machine during spin-drying operations.
Implementation Method 1
an alternating current (AC) motor which generates torque
Implementation Method 2
a clutch assembly which selectively transfers the torque to a rotating tub and a pulsator
Implementation Method 3
laundry is spin-dried using a centrifugal force generated by rotation of a rotating tub
Data Source
AI summary
A washing machine includes an alternating current (AC) motor which generates torque, a clutch assembly which selectively transfers the torque to a rotating tub and a pulsator, a speed detector which detects a rotary speed of the clutch assembly, and a controller configured to repetitively perform operating and stopping the operating of the AC motor based on a predetermined target speed and the rotary speed of the clutch assembly in a spin-drying operation. The controller gradually increases the torque of the AC motor while operating the AC motor.