The most reliable multipole avionics signal relay?

[peter-h]

Of the various multipole relays used for switching avionics signals, which would you say are really reliable?

There are the common ones like these
http://www.aircraftspruce.com/catalog/avpages/ameri_remote.php
http://www.aircraftspruce.com/catalog/avpages/remoteswitchrelay.php

but I wonder if they are any good...

The 2nd one is gas filled and should be a lot more reliable.

 

[SCCutler]

Peter:

Both reference "nitrogen filled" in the description.

This is such bone-stupid-simple tech, I'd buy whatever did the job for the least money.

 

[jhausch]

The most reliable relay is the one connected to the hobbs meter.

 

[peter-h]

I wonder what relays they use, because the normal nitrogen-filled relays are not exactly small e.g.

https://www.c3controls.com/cms/pdf/GP-Relay-brochure.pdf
http://www.omron-ap.com/product_info/MY4H/index.asp
http://www.lpa-group.com/Hermetically-Sealed-Relays-63-49-37-MR22.aspx
http://www.stpigroup.com/index.php?p=result&f=C7

However, small ones evidently do exist, albeit at very high prices:

http://www.sandia.aero/?q=system/files/MARC70_12-08.pdf
http://www.sandia.aero/?q=SR263

Reliability is desirable because if you are switching say 10 signals using a box containing 3 relays, and one of those relays gets stuck, you are going to see the most weird avionics failure modes.

 

[gismo]

I wonder what relays they use, because the normal nitrogen-filled relays are not exactly small e.g.

https://www.c3controls.com/cms/pdf/GP-Relay-brochure.pdf
http://www.omron-ap.com/product_info/MY4H/index.asp
http://www.lpa-group.com/Hermetically-Sealed-Relays-63-49-37-MR22.aspx
http://www.stpigroup.com/index.php?p=result&f=C7

However, small ones evidently do exist, albeit at very high prices:

http://www.sandia.aero/?q=system/files/MARC70_12-08.pdf
http://www.sandia.aero/?q=SR263

Reliability is desirable because if you are switching say 10 signals using a box containing 3 relays, and one of those relays gets stuck, you are going to see the most weird avionics failure modes.

Any chance you could use a MD41-528 indicator/switch/relay? I've got one I'd love to sell (cheap). It was designed to complement a KLN89B or KLN94 on a 28v airplane. Here's one on eBay for more than I want to get:

http://www.ebay.com/itm/Used-MD41-528-NAV-GPS-Annuciator-Control-Unit-/180608944656

 

[weirdjim]

I've got something like 10,000 Omron sugar-cube size relays in the field and as yet, not a single failure. You are looking to pay a lot of money for something that is dirt cheap in the hopes of getting "reliability". Sorry, it doesn't work that way.

Jim

 

[Old Geek]

I've also used many thousands of Omron relays in my products with no problems. The only issues we've ever had were a batch of boards with unsealed power relays that our assembly shop washed by mistake, and trying to unsolder and reuse the smaller relays. Read and follow the data sheet and they seem to last forever.

 

[kontiki]

I've seen a lot of Leach Relays in large aircraft. They used to have a great design guide on line too. There is a lot to understand about relays. I did a quick search, maybe it's now Easterline and there is link to a design reference.

http://www.esterline.com/powersystems/Overview.aspx

http://www.esterline.com/powersystems/DesignReference/RelayHandbook.aspx

 

[Richard]

Is the purpose of the gas to regulate magnetic capacity?
Or,
Is the gas to regulate (ensure constantcy) bridging contact?

Honestly, I never had a reason to think this much about relays.

 

[Old Geek]

I'm guessing that any time you fill a relay with nitrogen, it's to eliminate oxygen and reduce oxidation of the contacts.