Electromagnetic Switch Starter Relay Surge Suppression
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Solution Overview
Problem
Electromagnetic switches in starters, particularly in automobiles with idling stop functions, face contact wear due to arc discharges caused by counter electromotive forces, and existing surge absorption methods reduce arc discharges to the point where contact cleaning is insufficient.
Innovation Solution
Incorporating a surge suppression device that absorbs part of the energy from the coil when the starter relay turns off, allowing a controlled arc current to flow between the contacts, thereby reducing wear and ensuring adequate cleaning of the contact surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diode is connected in parallel to the coil to absorb counter electromotive force, then contact wear is suppressed, but arc discharge between contacts becomes insufficient for cleaning
Solution Approach 1:
The surge absorption function is divided into two stages: a first surge absorption element (diode) that operates initially to suppress counter electromotive force and protect contacts, and a second surge absorption element (resistor) that activates subsequently to provide controlled arc discharge for contact cleaning. This segmentation allows each element to specialize in one function, resolving the contradiction between contact protection and cleaning effectiveness.
Solution Approach 2:
The surge absorption circuit transitions dynamically from a low-resistance state (diode conducting) to a high-resistance state (resistor conducting) as the counter electromotive force decays. This dynamic behavior automatically adjusts the arc discharge intensity: strong initially for protection, then controlled for cleaning, eliminating the need for complex control circuits while achieving both contact protection and cleaning.
2Ease of operation
If arc discharge is allowed to clean contact surfaces, then contact surfaces are cleaned, but contact wear increases due to excessive arc discharge
Solution Approach 1:
The first surge absorption element (diode) is positioned to activate beforehand and absorb the majority of counter electromotive force energy, cushioning the contacts from excessive arc discharge. The second element (resistor) then provides a controlled, reduced-level arc discharge for cleaning. This prior cushioning protects contacts while still allowing beneficial cleaning action.
Solution Approach 2:
The circuit changes the electrical parameters (resistance and current level) of the surge absorption path over time. Initially, the diode provides low resistance for high current suppression; then the resistor provides high resistance for low current controlled arc discharge. This parameter change enables the system to achieve both contact protection and cleaning by adjusting the arc discharge intensity at different stages.
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 effectively suppresses contact wear while maintaining sufficient arc discharge for cleaning, thereby extending the life of the contacts in electromagnetic switches.
Implementation Method 1
an electromagnetic switch mounted on a starter is configured to generate a counter electromotive force across a coil depending on the inductance of the coil when a starter relay is turned off to interrupt a current flowing through the coil
Implementation Method 2
connect a diode as a surge absorption element in parallel to the coil... since a current generated due to the counter electromotive force across the coil is absorbed by the diode, the counter electromotive force can be prevented from being applied to the starter relay
Implementation Method 3
If the counter electromotive force is applied to the starter relay, since an arc discharge occurs between the contacts of the starter relay, the contacts are worn
Implementation Method 4
it is known to clean the surfaces of the contacts of an electromagnetic relay by generating an appropriate arc discharge between the contacts to burn off oil or dust adhered to the contacts
Data Source
AI summary
An electromagnetic switch for a starter includes a coil that includes a first lead wire connected to a power supply side and a second lead wire connected to a ground side, the coil being supplied with an energization current through the first and second lead wires to form an electromagnet while a starter relay is on. The electromagnetic switch further includes a surge suppression device that absorbs part of energy emitted from the coil when the starter relay is turned from on to off so that a remaining part of the energy is applied to the starter relay to cause an arc current to flow between contacts of the starter relay.