Load Resistor Short-Circuit Protection via Spark Gap

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Solution Overview

Problem

Load resistors in electrical systems are prone to uncontrolled voltage flashovers due to overloading, which can lead to overheating, electrical conductivity of insulating materials, and potential explosions, posing a risk to personnel and equipment, especially in environments with explosive atmospheres.

Innovation Solution

A short-circuit protection device with two parallel heating coil sections forming a spark gap is introduced, which causes a controlled short circuit at a predetermined limit load, preventing uncontrolled discharges and ensuring safe energy reduction through a voltage flashover, thus avoiding risks to people and equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the load resistor is continuously loaded beyond its limit, then the electrical energy dissipation increases, but the insulating material becomes electrically conductive causing uncontrolled voltage flashover

Engineering Contradiction:
Improveelectrical energy dissipationVSAvoidelectrical insulation stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The short-circuit protection device is designed to preemptively counteract the harmful effect of continuous overload by causing a controlled voltage flashover at a predetermined, safe energy level. This preliminary protective action prevents the insulating material from reaching its breakdown point and becoming electrically conductive, thus avoiding uncontrolled flashovers.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The heating coil sections are configured with a spark gap distance that corresponds to a specific energy threshold. When this threshold is reached, the insulating material between the heating coil sections breaks down first, causing a controlled short circuit. This preliminary action occurs before the main insulating material of the load resistor is affected, preventing catastrophic failure.

Inventive Principle:
Principle #10Preliminary action

2Strength

If the metal jacket is closed for protection, then the mechanical protection improves, but the heat dissipation decreases leading to overheating

Engineering Contradiction:
Improvemechanical protectionVSAvoidheat dissipation
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The short-circuit protection device acts as an intermediary safety mechanism between the electrical energy input and the thermal management system. By providing a controlled discharge path at a predetermined energy level, it prevents the accumulation of excessive thermal energy that would otherwise occur in a closed metal jacket system, thus avoiding overheating without requiring the jacket to be open.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Power

If the voltage flashover occurs uncontrolled, then the energy release increases, but the risk of explosion and damage to personnel increases

Engineering Contradiction:
Improveenergy releaseVSAvoidexplosion risk
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The invention converts the potentially harmful uncontrolled voltage flashover into a beneficial controlled protective mechanism. By designing the heating coil sections with a predetermined spark gap, the harmful high-energy discharge is redirected to occur at a safe, lower energy level between the heating coil sections, protecting the load resistor and surrounding environment from catastrophic failure.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The short-circuit protection device extracts the dangerous voltage flashover function from the main load resistor system. The controlled discharge occurs in the heating coil sections with their specifically designed spark gap, separating this protective function from the main energy dissipation function of the load resistor, thus preventing damage to the load resistor and reduction of explosion risk.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If the short-circuit protection is added, then the safety against uncontrolled discharge improves, but the device complexity increases

Engineering Contradiction:
Improvesafety against uncontrolled dischargeVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The short-circuit protection function is merged with the existing load resistor structure by integrating the heating coil sections into the load lines. This combination allows the protective function to be achieved without adding a completely separate device, thus limiting the increase in device complexity while still providing reliable protection against uncontrolled discharge.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heating coil sections serve dual functions: they are part of the load resistor structure for energy dissipation and simultaneously form the short-circuit protection device with the spark gap. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving the safety improvement.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 prevents uncontrolled discharges and overheating, ensuring safe energy dissipation within the short-circuit protection device, thereby enhancing personal safety and preventing damage to the load resistor and surrounding environment.

Implementation Method 1

two heating coil sections running parallel to one another, which form a spark gap and cause a short circuit due to a voltage flashover when a limit load predetermined by the load resistance is reached

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the two heating coil sections form a kind of spark gap, the size of which is to be set as a function of the limit load determined by the load resistance

Methodology Applied
Scientific EffectElectrical breakdown: Electric Spark

Data Source

PatentEP2221834B1Load resistor with defined short circuit protection
Publication Date: 2011.09.21 TUERK & HILLINGER GMBH & CO
  • EP2221834B1 patent drawingFigure 1~2
  • EP2221834B1 patent drawingFigure 3
  • EP2221834B1 patent drawingFigure 4~5

AI summary

The power resistance (1) has at least one resistance element (5) as a spiral (6) with two electrical connections (13,14) at the power line (15,16). A short circuit protection (2) has two electrodes (24,25) in a common housing (20), electrically linked to the connections, forming a spark gap (26) between them. They form a short circuit when a voltage overload breaches a threshold.