[volt-nuts] Latching Low Thermal EMF Relays

George Atkinson robertg8rpi at virginmedia.com
Fri Jul 11 16:58:34 EDT 2014


Hi,
The problem is that most low thermal EMF relays (COTO, Picckering etc) use
reed contacts for environment reasons, but reeds are not easy to latch.
The good news is that the Omron G6 range has the options you require (and
just about any other small relay option).
for example the G6AK-274P-STLT-US-DC5 which is dual coil latching, 5v coils
and low thermal EMF. It's about $10 from Mouser. The critical parts of the
number are AK for dual coil latching, AU for single coil latching and STLT
for low thermal EMF  DCx is coil voltage, between 3 and 28V.
Datasheet here http://www.mouser.com/ds/2/307/G6A_0911-4215.pdf

HTH,
Robert G8RPI.

P.S. Relay contact technology is fascinating. I once specified a lamp rated
(added cadmium in contacts) version of a relay. It was controlled by a PIC
driving 3 linear halogen lamps (see patent US7247429
<http://worldwide.espacenet.com/publicationDetails/originalDocument?FT=D&date=20070724&DB=EPODOC&locale=en_EP&CC=US&NR=7247429B2&KC=B2&ND=5>
). A couple of years in production decided that a single letter change in
the part number of the relay didn't matter and saved a couple of dollars.
Guess what, we got failures with welded contacts (fortunatly I'd put a
thermal cutout in series with the lamps, mostly incase my PIC code fell
over, so no fires :-) Took a while before field service caomplained about
poor design......
Then there are the low level and power rated relays that use a gold flash
over silver. Trouble is if you use it for power they will fail in low level
use. A lot of mil-spec relays use this trick and I've seen problems where
relay swapping for fault finding has swapped a low level with a power and
back. No initial problem, but months later the contacts have gone high.
Then there was the supplier who tested all the new relays - under load, DOH!


On 11 July 2014 19:15, Randy Evans <randyevans2688 at gmail.com> wrote:

> That is an assembly but I am looking for an individual relay part that I
> can put on a PCB.
>
> Randy
>
>
> On Fri, Jul 11, 2014 at 7:15 AM, Wim de Jong <wim.de.jong.59 at solcon.nl>
> wrote:
>
> > The http://www.transmille.co.uk/8500.htm
> >
> > Wim de Jong
> >
> > _______________________________________________
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