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Need a hermetic sealed high current relay

  • Thread starter Klaus Kragelund
  • Start date
K

Klaus Kragelund

Jan 1, 1970
0
Hi

As the subject states I am in the need of a hermetic sealed relay for
ac currents up to a couple of amps.

The product is submerged in water and the electronics (PCB including
relay) is potted toallow a small concentration of water in the potting
compound (to get high resistance between any two given points)

But, we would very much so like to use a relay in this project.We
could use a standard one, but this has air inside and is not sealed.So
eventually the potting compound would be saturated by water and water
would travel through the relay walls and into the mechanics of the
relay destoying it.

So we are looking for a high current relay that is sealed (glass
sealed).Do any of you guys know of one?

Regards

Klaus
 
J

John Larkin

Jan 1, 1970
0
Hi

As the subject states I am in the need of a hermetic sealed relay for
ac currents up to a couple of amps.

The product is submerged in water and the electronics (PCB including
relay) is potted toallow a small concentration of water in the potting
compound (to get high resistance between any two given points)

But, we would very much so like to use a relay in this project.We
could use a standard one, but this has air inside and is not sealed.So
eventually the potting compound would be saturated by water and water
would travel through the relay walls and into the mechanics of the
relay destoying it.

So we are looking for a high current relay that is sealed (glass
sealed).Do any of you guys know of one?

Regards

Klaus


Kilovac. Or Gigavac. Big bucks.

Or a power reed, although I don't really trust them for reliability.

Why not a solid state relay?

John
 
A

Arlet Ottens

Jan 1, 1970
0
Klaus said:
Hi

As the subject states I am in the need of a hermetic sealed relay for
ac currents up to a couple of amps.

The product is submerged in water and the electronics (PCB including
relay) is potted toallow a small concentration of water in the potting
compound (to get high resistance between any two given points)

But, we would very much so like to use a relay in this project.We
could use a standard one, but this has air inside and is not sealed.So
eventually the potting compound would be saturated by water and water
would travel through the relay walls and into the mechanics of the
relay destoying it.

So we are looking for a high current relay that is sealed (glass
sealed).Do any of you guys know of one?

Regards

Klaus

How about this one ?

http://www.cotorelay.com/html/reed_relay_5500_series.htm
 
K

Ken S. Tucker

Jan 1, 1970
0
Hi

As the subject states I am in the need of a hermetic sealed relay for
ac currents up to a couple of amps.

The product is submerged in water and the electronics (PCB including
relay) is potted toallow a small concentration of water in the potting
compound (to get high resistance between any two given points)

But, we would very much so like to use a relay in this project.We
could use a standard one, but this has air inside and is not sealed.So
eventually the potting compound would be saturated by water and water
would travel through the relay walls and into the mechanics of the
relay destoying it.

So we are looking for a high current relay that is sealed (glass
sealed).Do any of you guys know of one?

Regards

Klaus

Just put the relays in a plastic bag. Silicon seal where
the wires come out. Recall that leakage requires a
pressure differential, and none occurs through the
seal. The bag shinks to equalize the ambient pressure.
Ken
 
K

Klaus Kragelund

Jan 1, 1970
0
Kilovac. Or Gigavac. Big bucks.

Or a power reed, although I don't really trust them for reliability.

Why not a solid state relay?

John- Skjul tekst i anførselstegn -

- Vis tekst i anførselstegn -

We have been using a solid state relay (two N-channel MOSFETs in anti
series connection), but they get too hot and we need terrible derating
if they are to survive a high current surge.

So our approach may be to use a Triac to turn on the product (motor)
and energizing the relay at the same time (so the relay takes all the
current after 1 mains half-cycle (10ms). Likewise when the motor is
turned off, the triac is turned on, the relay turned off and the the
triac turned off again (so the relay never actually breaks a current)

Moreover the solid state relay costs 8 USD, so we hope to find a
cheaper relay than that

regards

Klaus
 
J

Jan Panteltje

Jan 1, 1970
0
I have seen potted electronics that had water in them (porous),
they failed.
Copper oxide, all green, traces broken, a big mess.
Unless it is for very shot duration (some hours, and not even
salty water, or any not purified water sounds like asking for disaster to me.
 
J

Joerg

Jan 1, 1970
0
Klaus said:
Hi

As the subject states I am in the need of a hermetic sealed relay for
ac currents up to a couple of amps.

The product is submerged in water and the electronics (PCB including
relay) is potted toallow a small concentration of water in the potting
compound (to get high resistance between any two given points)

But, we would very much so like to use a relay in this project.We
could use a standard one, but this has air inside and is not sealed.So
eventually the potting compound would be saturated by water and water
would travel through the relay walls and into the mechanics of the
relay destoying it.

So we are looking for a high current relay that is sealed (glass
sealed).Do any of you guys know of one?

I don't know how well these would perform but they cost above $20:

http://oeiwcsnts1.omron.com/pdfcatal.nsf/0/04012CD21AE4D84986256FC70060FA0D/$file/D20MY4H0305.pdf

Digikey has them. Theirs are not rated for EU voltages though, all US
(120V). I would contact them about it, plus maybe some other relay
companies like Weidmuller, Panasonic Electric Works, Phoenix,
Potter&Brumfield (now a Tyco division), etc.

Also, you could check with folks from undersea exploration businesses
(submarines) and oil/gas exploration suppliers.

These guys know a whole lot about this stuff:
http://www.schilling.com/
 
K

Klaus Kragelund

Jan 1, 1970
0
I have seen potted electronics that had water in them (porous),
they failed.
Copper oxide, all green, traces broken, a big mess.
Unless it is for very shot duration (some hours, and not even
salty water, or any not purified water sounds like asking for disaster to me.

We have field test trials submerged under pressure that has run for
about a year now. No problems yet :)

its a matter of finding the optimum potting compound that will glue
onto the parts and PCB (VDE demands a sticky test - if I use the
correct termI hope)

Regards

Klaus
 
J

Jamie

Jan 1, 1970
0
Klaus said:
Hi

As the subject states I am in the need of a hermetic sealed relay for
ac currents up to a couple of amps.

The product is submerged in water and the electronics (PCB including
relay) is potted toallow a small concentration of water in the potting
compound (to get high resistance between any two given points)

But, we would very much so like to use a relay in this project.We
could use a standard one, but this has air inside and is not sealed.So
eventually the potting compound would be saturated by water and water
would travel through the relay walls and into the mechanics of the
relay destoying it.

So we are looking for a high current relay that is sealed (glass
sealed).Do any of you guys know of one?

Regards

Klaus
Reed or
Vacuum relays.

Most likely a Reed type will work for you.
http://www.cotorelay.com/html/reed_relay___dry_reed_switch_p.htm
 
W

whit3rd

Jan 1, 1970
0
...we would very much so like to use a relay in this project.We
could use a standard one, but this has air inside and is not sealed.

As others have stated, reed relays are usually glass/metal sealed
and can be potted without mechanical interference. There are also
mercury relays that have all moving parts inside a glass capsule.

Reed relays that are suitable for motor switching might exist,
but the usual uses are small-signal; a 2A motor will require
contacts rated at higher than 2A...
 
R

Rich Grise

Jan 1, 1970
0
So we are looking for a high current relay that is sealed (glass
sealed).Do any of you guys know of one?

I've seen mercury contactors, but they have to be kept vertical,
and I'm only ass-u-me-ing that they're waterproof, since they
seem to manage to keep the mercury inside. :)

Good Luck!
Rich
 
J

Joerg

Jan 1, 1970
0
Rich said:
I've seen mercury contactors, but they have to be kept vertical,
and I'm only ass-u-me-ing that they're waterproof, since they
seem to manage to keep the mercury inside. :)

Those might be off limits by now. Probably even more so in Europe.
 
J

Jan Panteltje

Jan 1, 1970
0
We have field test trials submerged under pressure that has run for
about a year now. No problems yet :)

its a matter of finding the optimum potting compound that will glue
onto the parts and PCB (VDE demands a sticky test - if I use the
correct termI hope)

Oh, I see, if it sticks then it is like a coating.
Still personally I would avoid it :)
 
J

JosephKK

Jan 1, 1970
0
Klaus Kragelund [email protected] posted to
sci.electronics.design:
Hi

As the subject states I am in the need of a hermetic sealed relay
for ac currents up to a couple of amps.

The product is submerged in water and the electronics (PCB including
relay) is potted toallow a small concentration of water in the
potting compound (to get high resistance between any two given
points)

But, we would very much so like to use a relay in this project.We
could use a standard one, but this has air inside and is not
sealed.So eventually the potting compound would be saturated by
water and water would travel through the relay walls and into the
mechanics of the relay destoying it.

So we are looking for a high current relay that is sealed (glass
sealed).Do any of you guys know of one?

Regards

Klaus

Probably a tad expensive but would something like this do what you
want?
http://www.relays-r-us.co.uk/webpages/products/bc_cat_index/JQX15M.htm

From an item on the first page of a google search of:
hermetically sealed relay
 
C

ChairmanOfTheBored

Jan 1, 1970
0
Klaus Kragelund [email protected] posted to
sci.electronics.design:


Probably a tad expensive but would something like this do what you
want?
http://www.relays-r-us.co.uk/webpages/products/bc_cat_index/JQX15M.htm

From an item on the first page of a google search of:
hermetically sealed relay


Oh boy! It is rated at a whole TEN AMPS!

Why not try a SOLID STATE relay, and pot the thing in something that
will NOT allow water to infiltrate, like a polyurethane potting compound,
like Conap EN-12 or such.

http://www.matweb.com/search/datasheettext.aspx?matid=29247
 
W

Wim Ton

Jan 1, 1970
0
Ken said:
Just put the relays in a plastic bag. Silicon seal where
the wires come out. Recall that leakage requires a
pressure differential, and none occurs through the
seal. The bag shinks to equalize the ambient pressure.
Ken
Water still creeps between the silicone and the wires (IFAIR a remark
from a mechanic that maintained well logging equipment, although we are
talking 300-400 bar @100 degrees Celcius here)

Wim
 
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