Washing Machine Drain Pump Cut-Wave Control for Low-Flow Phases
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Solution Overview
Problem
Existing washing machine control systems waste energy and cause mechanical stress by continuously powering or shutting down the drainage pump motor during phases with minimal water flow, leading to reduced motor lifespan and vibrations.
Innovation Solution
Implementing a control device that switches the drainage pump motor to a cut-wave mode during phases with minimal water flow, applying a constant delay time in each half-cycle of the mains voltage to reduce power consumption and prevent sudden mechanical stress, using existing triac switches and zero setting points for ease of integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the discharge motor is continuously powered during phases with minimal water flow, then the motor remains ready to drain water immediately, but energy is wasted and mechanical stress increases
Solution Approach 1:
The patent applies periodic action by switching the discharge motor between full-wave mode (when water needs draining) and cut-wave mode (during phases with minimal water flow). The control device periodically adjusts the power supply to the motor based on the washing program phase, applying a constant delay time in each half-cycle to reduce power consumption while maintaining operational readiness when needed.
2Loss of energy
If the discharge motor is switched on and off continuously, then power consumption is reduced, but sudden mechanical stresses and vibrations occur
Solution Approach 1:
The patent applies dynamics by transitioning from binary on-off control to a dynamic cut-wave control mode. Instead of abrupt switching, the control device dynamically adjusts the power supply waveform by applying a constant delay time parameter, creating a gradual transition that reduces mechanical stress and vibrations while maintaining energy efficiency.
3Speed
If the discharge motor operates in full-wave mode during phases with minimal water flow, then immediate drainage response is maintained, but the motor lifespan is reduced due to continuous operation
Solution Approach 1:
The patent applies parameter changes by modifying the power supply characteristics to the discharge motor. The control device changes the voltage waveform parameter by applying a constant delay time in each half-cycle, transitioning from full-wave to cut-wave mode. This parameter adjustment reduces the effective voltage and current, lowering mechanical stress and extending motor lifespan while maintaining sufficient drainage capability when needed.
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 reduces power consumption, prolongs the motor's lifespan, minimizes vibrations and mechanical stress by optimizing the drainage pump's operation based on the washing program phases, without requiring additional sensors.
Implementation Method 1
The time reference that is normally used to carry out the phase control of the main motor is the zero setting of the mains voltage
Implementation Method 2
the effective voltage (or RMS voltage) applied to the discharge motor is reduced
Data Source
Figure 1~2
Figure 3~4
AI summary
A device and method for controlling a drainage pump of a washing machine. The drainage pump is powered by a discharge motor (3), the discharge motor (3) being a synchronous motor that is connected to a mains voltage (Vr) bus by a switch (5). During one or more stages of a washing program, the switch (5) is operated to apply in each half cycle of the mains voltage (Vr) a delay time (Tr) from the zero setting of the mains voltage to cause the discharge motor (3) to operate in a cut-wave mode.