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Reed Switch Blade Alignment Explained
Have you ever considered the importance of reed switch blade alignment to ensure long life and optimum performance when using reed relays? We have created a short video explaining how crucial blade alignment is within a reed relay.
Click play to watch the video below:
The reed switch is the most important part of a relay. They are sealed in a glass tube filled with inert gases or a vacuum. This sealing process holds the reeds in place, giving the required blade gap the right sensitivity and correct aligned overlap.
Why is it so important for blades to be aligned?
It is essential for blades to be parallel and aligned to ensure the maximum contact area when the blades come together. This provides the lowest contact resistance and the best contact resistance stability.
In misaligned switches, the blades do not come together correctly. This leads to a higher contact resistance and provides less area for heat dissipation during hot switching. These factors combined will lead to a lower performance and life expectancy of the reed relay.
Similarly, skewed blades will make an edge connection first, before completing the full contact. This will give higher, and unstable, contact resistances, as well as giving the blades uneven wear. Again, this will largely reduce the performance and life expectancy of the overall product.
How can blades be misaligned?
The first reason the blades may be misaligned is due to the manufacturing process of the switches themselves. Some relay manufacturers use lower cost parts and do not perform the testing required to eliminate the use of misaligned or skewed, non-parallel blades.
Blades can also become misaligned during the process of assembling the reed relay. Many moulding techniques require high pressure and temperatures. When this is combined with rigid moulding materials, these stresses can deflect the blades and result in misalignment.
Finally, external forces applied to the final product can also misalign the blades. This includes physical force, but also things such as competing magnetic fields.
How can misalignment be avoided?
All of our instrument-grade reed switches are tested for resistance stability, which ensures that they are correctly aligned before creating the relay. To ensure a long life and optimal performance, the reed switch also needs to be protected. Pickering’s solution to this is our SoftCenter™ technology; which provides the maximum cushioned protection of reed switches, without applying too much stress to the part. This will extend the working life and contact stability of the relay.
If you found this video helpful / interesting please take a look at our other useful videos which can be found here.
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