Electrical appliance with an electrical resistance heating element and method for operating an electrical appliance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrical appliances face challenges in reducing the number and effort of components required to limit inrush current when connecting to the main circuit, while maintaining reliability, as high initial currents can exceed nominal currents by up to 40 times, violating European appliance standards.
Innovation Solution
An electrical appliance with an electrical resistance heating element and a two-way switching means connects the heating element in series with the load or power regulating means, allowing it to function as an inrush current limiter, then disconnects after the initial pulse, allowing the heating element to operate independently for heating functions without additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a discharge capacitor is connected to the AC main circuit, then the electrical appliance can be switched on, but a high inrush current appears that can be up to 40 times higher than the nominal current
Solution Approach 1:
The heating element is used as an intermediary component to limit inrush current. During the switching-on phase, it acts as a current-limiting resistor in series with the discharge capacitor, protecting the circuit from excessive current while allowing the appliance to be switched on normally.
Solution Approach 2:
The heating element serves dual functions: it limits inrush current during switching-on and performs its primary heating function during operation. This eliminates the need for separate inrush current limiting components, reducing overall device complexity.
2Object-affected harmful factors
If a current limiter component such as a large and robust resistor is connected in series with the discharge capacitor, then the inrush current is limited, but the number of components and effort increase
Solution Approach 1:
The heating element is repurposed to serve as the inrush current limiting component, eliminating the need for separate resistors or NTC elements. This multi-functional approach reduces the number of components while maintaining effective current limiting.
Solution Approach 2:
The heating element serves itself by performing both its primary heating function and the secondary function of limiting inrush current. This self-service approach eliminates the need for additional dedicated components for current limiting.
3Object-affected harmful factors
If an NTC element is used for limiting the capacitor charge current, then the inrush current is limited, but the reliability may be compromised
Solution Approach 1:
The heating element is used for both heating and inrush current limiting, eliminating reliance on NTC elements that may have reliability issues. This approach uses a robust, simple resistive element that can withstand repeated inrush current pulses without degradation.
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 solution reduces the number of components needed to manage inrush current, maintaining reliability and efficiency by utilizing existing heating elements and switching means, minimizing heating energy consumption during the brief inrush current period.
Implementation Method 1
An electrical appliance with an electrical resistance heating element and a two-way switching means connects the heating element in series with the load or power regulating means, allowing it to function as an inrush current limiter
Implementation Method 2
the heating element to function as an inrush current limiter
Data Source
Figure 1~5
Figure 6~3
AI summary
An electrical appliance has an electrical resistance heating element, an electrical load such as an electrical motor, a switching means with one input and two outputs, wherein the input can be switched to either one of the two outputs, wherein the second output is connected to the second pole of the feed voltage and the first output is connected to the electrical load and/or to power regulating means for the electrical load. The electrical resistance heating element has two connectors, wherein a first connector is connected to a first pole of a feed voltage and wherein a second connector is connected to the input of a switching means.