Relay Contact Assembly Layout for DC Short-Circuit Arcing
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Solution Overview
Problem
High-voltage DC relays face challenges with heat loss, anti-short circuit current capacity, and anti-short circuit voltage capacity, leading to contact bouncing and arcing due to electrodynamic repulsion forces, which existing solutions cannot adequately address while meeting requirements of small volume and low power consumption.
Innovation Solution
The relay design incorporates a contact assembly with inner contact portions on the stationary contact lead-out terminals, reducing electrodynamic repulsion forces by ensuring current paths are close to the center line of the movable contact piece, and an anti-short circuit assembly using magnets to resist faulty high currents, without increasing volume or size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the coil size is increased to improve holding force, then the anti-short circuit current voltage capacity is improved, but the volume and power consumption increase
Solution Approach 1:
The patent applies local quality by creating an inner contact portion with different geometric properties than the outer contact surface. The inner contact portion has a smaller radius of curvature and is positioned closer to the center line, creating localized structural differentiation that reduces electrodynamic repulsion without requiring overall coil enlargement
Solution Approach 2:
The patent introduces a new spatial dimension by positioning the inner contact portion at a different radial distance from the center line compared to traditional contact designs. This dimensional change in contact geometry allows the current path to be optimized for reduced electrodynamic repulsion while maintaining compact overall dimensions
2Reliability
If the contact pressure is increased to reduce contact resistance, then the contact resistance is reduced, but the electrodynamic repulsion force cannot be resisted and volume increases
Solution Approach 1:
The inner contact portion creates local structural differentiation with optimized geometric properties. By positioning the contact area closer to the center line and reducing the radius of curvature, the design locally enhances mechanical strength to resist electrodynamic repulsion forces without requiring overall contact pressure increase
Solution Approach 2:
The recess structure is pre-formed in the contact lead before operation. This preliminary geometric configuration ensures that during short-circuit conditions, the inner contact portion naturally resists electrodynamic repulsion through its pre-positioned geometry rather than relying on increased contact pressure
3Reliability
If the coil ampere-turn value is increased to improve holding force, then the anti-short circuit current capacity is improved, but the power consumption increases
Solution Approach 1:
The patent applies local quality by creating an inner contact portion with different geometric properties than the outer contact surface. The inner contact portion has a smaller radius of curvature and is positioned closer to the center line, creating localized structural differentiation that reduces electrodynamic repulsion without requiring overall coil enlargement
Solution Approach 2:
The patent introduces a new spatial dimension by positioning the inner contact portion at a different radial distance from the center line compared to traditional contact designs. This dimensional change in contact geometry allows the current path to be optimized for reduced electrodynamic repulsion while maintaining compact overall dimensions
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 design effectively reduces electrodynamic repulsion forces, preventing arcing and improving safety while maintaining a lightweight and compact form factor, thus enhancing the relay's performance in high-voltage DC applications.
Implementation Method 1
the electrodynamic repulsion forces generated by the short-circuit current, and then contact arcing will occur
Implementation Method 2
an anti-short circuit assembly using magnets to resist faulty high currents
Data Source
Figure 1~2
Figure 3~6
Figure 7~10
AI summary
A relay includes a contact assembly (2), the contact assembly (2) includes a movable contact piece (22) and a pair of stationary contact lead-out terminals (21), movable contact piece (2) is configured to contact with or separate from the pair of stationary contact lead-out terminals (21). At least one of the sides of the stationary contact lead-out terminals (21) and the movable contact piece (22) close to each other is provided with an inner contact portion (20), and the stationary contact lead-out terminals (21) and the movable contact piece (22) are abutted only by the inner contact portion (20), and the inner contact portion (20) is disposed on a side where the pair of stationary contact lead-out terminals (21) are close to each other.