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
Add your own solenoid.
RL
RL
This will handle 100A:
But you might need to build the 3Ph to DC converter.
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
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.
??
I'm switching 3ph 208 VAC. SSR's are not usable; 1.4V drop * 3 * 100A = 420 watts of heat to sink per relay.
Have you looked at companies making star/delta soft starter relays ?
You might find some relays with NC or switch over contacts.
look at 3 pole lighting contactors.
Also, automatic transfer switch 3 pole contactors.
What Philbrook said: Automatic transfer switch. Some manufacturers I've had GOOD experience with: Onan / Cummins Russelectric (Expensive!, but wonderful equipment!!) Caterpillar / CAT Koheler, but I don't recall if they make their own 3-Ph units?
"OK" Experience: Camsco
BAD Experience: Zenith - Holds the World Record for sloppiest re-transfer in-sync monitor. (Actually, the phase monitor ain't bad, it's the switch that truly sucks!) They probably don't even make these anymore?
The above assumes a one-off "project". If you're looking to roll-your-own design, then ignore the above - although researching the respective designs may give you some ideas.
You probably did more research than me; so, i'll take your words for it. Voltage drop of 1.4V seems too high and the 3ph factor is more than 1, but less than 3.
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
Or pay someone to turn it for us....
-- A host is a host from coast to snipped-for-privacy@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
NO not NC main contacts.
-- A host is a host from coast to snipped-for-privacy@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
Again NO not NC; further 1.5v Vfwd * 3 phases * 100A * 24 circuits == many watts of heat.
Yes....
-- A host is a host from coast to snipped-for-privacy@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
None appear to be NC 100A....
-- A host is a host from coast to snipped-for-privacy@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
Nope. I want a relay with NC contacts; Form B...
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