Pump Triac Feedback Control to Prevent Washer Motor Overheating
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Solution Overview
Problem
Household appliance pumps used in washing and drying processes often overheat due to exposure to direct current, leading to potential fires, and existing solutions rely on costly thermal protectors or incorrect triac failure detection.
Innovation Solution
A microprocessor-controlled system with a feedback circuit using electronic elements like resistors detects diode mode failures in the pump triac, cutting off power to prevent overheating and allowing reoperation after cooling, eliminating the need for thermal protectors and reducing unnecessary malfunction modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermal protector is used to prevent pump motor overheating, then the motor is protected from direct current exposure, but the component cost and labor cost increase
Solution Approach 1:
The patent replaces the mechanical thermal protector component with an electronic control system. The microprocessor monitors the triac state through feedback circuitry and controls the pump motor operation accordingly, eliminating the need for physical thermal protection components while achieving the same safety function through software-based detection and response
Solution Approach 2:
The patent implements a feedback mechanism where the microprocessor continuously monitors the triac operation through connected feedback circuitry. When the triac is detected to be in diode mode (faulty state), the system automatically responds by stopping the pump motor, creating a closed-loop control system that provides active protection without additional hardware components
2Measurement precision
If the microprocessor detects triac failures accurately, then false malfunction detections are reduced, but the detection system complexity increases
Solution Approach 1:
The patent employs feedback circuitry connected between the triac and microprocessor that monitors the electrical state of the triac. By analyzing the feedback signal characteristics, the microprocessor can distinguish between genuine triac failures and normal operating variations, achieving accurate detection without requiring complex external diagnostic equipment
Solution Approach 2:
The system uses its own existing microprocessor and feedback circuitry to perform self-diagnosis of the triac state. Rather than requiring separate detection devices or external monitoring systems, the control system monitors itself, eliminating the need for additional detection hardware while maintaining high detection accuracy
Data Source
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AI summary
The present invention relates to a household appliance (1) which comprises a pump (2) that provides the water to be circulated or discharged in washing and/or drying processes and that is driven by a pump triac (3); and wherein the overheating of the pump (2) motor is prevented without using thermal protector. The household appliance (1) has preferably the feature of washing laundry and comprises a drum wherein laundry is emplaced, a door providing access to the drum, a door lock (6) controlled by the microprocessor (5), preventing the door from being opened by being locked during washing and allowing the door to be opened at the end of the washing process, a door lock triac (7) providing the door lock (6) to be driven with alternating current (AC), a drum motor (8) providing the drum to be rotated, a drum motor triac (9) driving the drum motor (8), a heater (10) providing the washing water to be heated and a heater relay (11) providing the heater (10) to be turned on and off.