EDAboard.com | EDAboard.de | EDAboard.co.uk | WTWH Media

Contactors/Relays

Ask a question - edaboard.com

elektroda.net NewsGroups Forum Index - Electronics Components - Contactors/Relays

Goto page 1, 2, 3  Next

David Lesher
Guest

Sat Oct 14, 2017 8:16 pm   



I have futilely been seeking 100A 3ph NC/Form B relays/contactors.
It seems they are all stashed in the "unicorn eggs" box, sigh.

So a second design approach involves dual coil relays. The
flavor I seek has one larger coil to close the relay, and a
second, much lower power holding coil to keep it closed. Of
course, I'm not finding them either. The ones I unearth are
"close coil, open coil" flavor.

Anyone seen such?

legg
Guest

Sat Oct 14, 2017 9:38 pm   



On Sat, 14 Oct 2017 18:16:57 +0000 (UTC), David Lesher
<wb8foz_at_panix.com> wrote:

Quote:
I have futilely been seeking 100A 3ph NC/Form B relays/contactors.
It seems they are all stashed in the "unicorn eggs" box, sigh.

So a second design approach involves dual coil relays. The
flavor I seek has one larger coil to close the relay, and a
second, much lower power holding coil to keep it closed. Of
course, I'm not finding them either. The ones I unearth are
"close coil, open coil" flavor.

Anyone seen such?


Are you still insisting on DIN rail mounting?

RL

legg
Guest

Sat Oct 14, 2017 9:52 pm   



On Sat, 14 Oct 2017 18:16:57 +0000 (UTC), David Lesher
<wb8foz_at_panix.com> wrote:

Quote:
I have futilely been seeking 100A 3ph NC/Form B relays/contactors.
It seems they are all stashed in the "unicorn eggs" box, sigh.

So a second design approach involves dual coil relays. The
flavor I seek has one larger coil to close the relay, and a
second, much lower power holding coil to keep it closed. Of
course, I'm not finding them either. The ones I unearth are
"close coil, open coil" flavor.

Anyone seen such?



https://www.galco.com/shop/Open-Transfer-Switches

Add your own solenoid.

RL

legg
Guest

Sat Oct 14, 2017 10:20 pm   



On Sat, 14 Oct 2017 18:16:57 +0000 (UTC), David Lesher
<wb8foz_at_panix.com> wrote:

Quote:
I have futilely been seeking 100A 3ph NC/Form B relays/contactors.
It seems they are all stashed in the "unicorn eggs" box, sigh.

So a second design approach involves dual coil relays. The
flavor I seek has one larger coil to close the relay, and a
second, much lower power holding coil to keep it closed. Of
course, I'm not finding them either. The ones I unearth are
"close coil, open coil" flavor.

Anyone seen such?


http://gencontrol.co.uk/3-pole--9a-95a--nc1-type-.html

RL

Hul Tytus
Guest

Sat Oct 14, 2017 11:20 pm   



David - are the "close coil, open coil" relays the type that are opened by
a pulse on one coil and closed by a pulse on the other?

Hul

In sci.electronics.design David Lesher <wb8foz_at_panix.com> wrote:
Quote:
I have futilely been seeking 100A 3ph NC/Form B relays/contactors.
It seems they are all stashed in the "unicorn eggs" box, sigh.

So a second design approach involves dual coil relays. The
flavor I seek has one larger coil to close the relay, and a
second, much lower power holding coil to keep it closed. Of
course, I'm not finding them either. The ones I unearth are
"close coil, open coil" flavor.

Anyone seen such?


John Larkin
Guest

Sun Oct 15, 2017 1:43 am   



On Sat, 14 Oct 2017 18:16:57 +0000 (UTC), David Lesher
<wb8foz_at_panix.com> wrote:

Quote:
I have futilely been seeking 100A 3ph NC/Form B relays/contactors.
It seems they are all stashed in the "unicorn eggs" box, sigh.

So a second design approach involves dual coil relays. The
flavor I seek has one larger coil to close the relay, and a
second, much lower power holding coil to keep it closed.


AC relays and contactors do that automatically. The seated inductance
is much higher than the open inductance, so the coil current drops
when the relay is fully closed.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics


Guest

Sun Oct 15, 2017 9:20 am   



On Sat, 14 Oct 2017 18:16:57 +0000 (UTC), David Lesher
<wb8foz_at_panix.com> wrote:

Quote:
I have futilely been seeking 100A 3ph NC/Form B relays/contactors.
It seems they are all stashed in the "unicorn eggs" box, sigh.

So a second design approach involves dual coil relays. The
flavor I seek has one larger coil to close the relay, and a
second, much lower power holding coil to keep it closed. Of
course, I'm not finding them either. The ones I unearth are
"close coil, open coil" flavor.

Anyone seen such?


Have you looked at companies making star/delta soft starter relays ?

You might find some relays with NC or switch over contacts.

Neon John
Guest

Sun Oct 15, 2017 3:49 pm   



On Sat, 14 Oct 2017 18:16:57 +0000 (UTC), David Lesher
<wb8foz_at_panix.com> wrote:

Quote:
I have futilely been seeking 100A 3ph NC/Form B relays/contactors.
It seems they are all stashed in the "unicorn eggs" box, sigh.

So a second design approach involves dual coil relays. The
flavor I seek has one larger coil to close the relay, and a
second, much lower power holding coil to keep it closed. Of
course, I'm not finding them either. The ones I unearth are
"close coil, open coil" flavor.


With a DC coil, you can very easily make a peak/hold circuit. Place a
power resistor in series with the coil, the value of which sets the
holding current. Bridge that resistor with a fairly large value
capacitor.

The way it work is that when power is applied, the capacitor shunts
the resistor with zero impedance and supplies full voltage to the
coil. As the capacitor charges, it becomes an open circuit and the
resistor controls the holding current.

The easiest way to select the capacitor is trial and error.

One thing to be aware of. If there is vibration involved then you
must set the holding current high enough to keep the armature pulled
in despite the vibration.

John

John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address

David Lesher
Guest

Thu Oct 19, 2017 12:32 am   



legg <legg_at_nospam.magma.ca> writes:


>Are you still insisting on DIN rail mounting?

No, but that's the least important aspect.... not finding any mounting type...

legg
Guest

Thu Oct 19, 2017 5:11 am   



On Wed, 18 Oct 2017 22:32:46 +0000 (UTC), David Lesher
<wb8foz_at_panix.com> wrote:

Quote:
legg <legg_at_nospam.magma.ca> writes:


Are you still insisting on DIN rail mounting?

No, but that's the least important aspect.... not finding any mounting type...


This 'fail closed' issue may be a misconception. What mode of failure
are you anticipating this to cover?

If there is energy available on either terminal of the open contacts,
it should be harnessed to develope the required switch circuit state.
If there is no power on either terminal, then its state doesn't
matter.

RL

David Lesher
Guest

Thu Oct 19, 2017 8:03 am   



legg <legg_at_nospam.magma.ca> writes:

Quote:
Anyone seen such?



https://www.galco.com/shop/Open-Transfer-Switches

Add your own solenoid.


Or pay someone to turn it for us....

--
A host is a host from coast to coast.................wb8foz_at_nrk.com
& no one will talk to a host that's close..........................
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

David Lesher
Guest

Thu Oct 19, 2017 8:04 am   



legg <legg_at_nospam.magma.ca> writes:

Quote:


NO not NC main contacts.
--
A host is a host from coast to coast.................wb8foz_at_nrk.com
& no one will talk to a host that's close..........................
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

David Lesher
Guest

Thu Oct 19, 2017 8:07 am   



Hul Tytus <ht_at_panix.com> writes:

Quote:
David - are the "close coil, open coil" relays the type that are opened by
a pulse on one coil and closed by a pulse on the other?


Yes....

--
A host is a host from coast to coast.................wb8foz_at_nrk.com
& no one will talk to a host that's close..........................
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

David Lesher
Guest

Thu Oct 19, 2017 8:11 am   



legg <legg_at_nospam.magma.ca> writes:


Quote:
This 'fail closed' issue may be a misconception. What mode of failure
are you anticipating this to cover?


Nope, it's what's needed....
Control power drops, relay contacts close.


--
A host is a host from coast to coast.................wb8foz_at_nrk.com
& no one will talk to a host that's close..........................
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

rickman
Guest

Thu Oct 19, 2017 9:49 am   



David Lesher wrote on 10/19/2017 2:04 AM:
Quote:
legg <legg_at_nospam.magma.ca> writes:

Anyone seen such?

http://gencontrol.co.uk/3-pole--9a-95a--nc1-type-.html

NO not NC main contacts.


Now I'm confused. Above you said if control power drops the relay contacts
should close. Here you say they should be NO. Those two things are not
compatible.

--

Rick C

Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998

Goto page 1, 2, 3  Next

elektroda.net NewsGroups Forum Index - Electronics Components - Contactors/Relays

Ask a question - edaboard.com

Arabic version Bulgarian version Catalan version Czech version Danish version German version Greek version English version Spanish version Finnish version French version Hindi version Croatian version Indonesian version Italian version Hebrew version Japanese version Korean version Lithuanian version Latvian version Dutch version Norwegian version Polish version Portuguese version Romanian version Russian version Slovak version Slovenian version Serbian version Swedish version Tagalog version Ukrainian version Vietnamese version Chinese version Turkish version
EDAboard.com map