Dishwasher Motor Current Sensing for Heater Overheating Prevention
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Solution Overview
Problem
Conventional dishwashers lack an effective method to sense the water level in the space with a heater, leading to potential overheating issues.
Innovation Solution
A dishwasher control method that uses a pump to supply water to a spray arm, measures the electric currents supplied to a motor to determine the water level, and adjusts the impeller rotation and water supply to prevent overheating by operating the heater only when a preset current level is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a water-level sensor is installed in the storage space to sense water level, then the heater overheating is prevented, but the device complexity increases
Solution Approach 1:
The pump motor serves dual functions: pumping water and sensing water level. The control unit monitors the motor's electric current to detect water level, eliminating the need for a separate water-level sensor. This self-service approach prevents heater overheating while avoiding additional device complexity
Solution Approach 2:
The pump motor is given multiple functions: it both pumps water from the sump to the spray arm and acts as a water-level sensor. By measuring the electric current consumed by the motor during operation, the system determines water level, thus one component performs multiple roles without increasing overall system complexity
2Productivity
If the impeller rotation speed is increased to spray water effectively, then the washing performance is improved, but the energy consumption increases
Solution Approach 1:
The impeller rotation speed is dynamically adjusted based on water level conditions. During the water supply phase, the impeller rotates at a first rotation speed to efficiently fill the housing. During the heating phase, it rotates at a second rotation speed to maintain water circulation without excessive energy consumption. This dynamic adjustment optimizes both washing performance and energy efficiency
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 the dishwasher to accurately sense the water level and prevent overheating, ensuring efficient and safe operation by controlling the heating process based on measured electric currents.
Implementation Method 1
a motor configured to rotate the impeller
Implementation Method 2
a heater provided in the housing... heating step of heating the washing water held in the housing by operating the heater
Implementation Method 3
an impeller provided in the housing, above the heater... driving step of rotating the impeller
Data Source
Figure 1
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AI summary
There is disclosed a dish washer and a control method for a dishwasher (100) including a spray arm (3, 5) configured to spray washing water to a washing object; a sump (13) configured to provide a space where the washing water is stored and to collect the washing water sprayed from the spray arm (3, 5); a housing (91) configured to connect the sump (13) and the spray arm (3, 5) with each other; a heater (98) provided in the housing (91); an impeller (96) provided in the housing (91), above the heater (98); and a motor (97) configured to rotate the impeller (96), the control method including a water supply step (S11) of supplying washing water to the sump (13); a driving step (S12) of rotating the impeller (96), using the electricity supplied to the motor (97); a measuring step (S14) of measuring the amount of the electric currents supplied to the motor (97) in the driving step (S12); and a heating step (S21) of heating the washing water held in the housing (91) by operating the heater (98), when the amount of the electric currents measured in the measuring step (S 14) is a preset reference amount or more.