[volt-nuts] Latching Low Thermal EMF Relays

[Randy Evans]

Thanks George,

I had looked at that part but the data sheet was confusing.  It did not
indicate how to specify low thermal emf or indicate what the emf voltage
is.  Am I just missing it?

Thanks again,

Randy


On Fri, Jul 11, 2014 at 1:58 PM, George Atkinson <
robertg8rpi at virginmedia.com> wrote:

> 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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