Shut off 3 phase supply

[Guest 004]

I need a solution for a problem I have, just cant seem to think at the moment.

I need to shut off a 3 phase supply when a supply to one phase has failed? Now I am thinking 4 pole contactor, but I am not sure of how to monitor the 3 individual phases on 1 control circuit? 3 control circuits perhaps?

 

[Gage]

Define failed... I'm probably missing something here because I'm zzzz but...3 Phase MCB?...

 

[High Tower]

use 3 single pole contactors with the 3 phases operating a (A1&A2) coil each, with the L1&L2 contacts in each wired in series to control the coil in a 4 pole contactor. Does that make sense?

 

[Guest 004]

^ need to elaborate a little on that HT

 

[Guest 004]

Define failed... I'm probably missing something here because I'm zzzz but...3 Phase MCB?...

Incoming supply where 1 phase goes down

 

[Guest 004]

@HT

Thinking maybe 3 double pole contactors, with one pole wired in series to feed a 4 pole contactor?

Is that what you meant?

 

[High Tower]

@HT

Thinking maybe 3 double pole contactors, with one pole wired in series to feed a 4 pole contactor?

Is that what you meant?

Pretty much yes

 

[Hawk81]

What about a phase failure relay controlling the contactor http://stevenengineering.com/Tech_Support/PDFs/45RPHS.pdf

 

[Guest 004]

^ thats the kiddy, nice and small as well.

 

[KINKY]

define failed... I'm probably missing something here because i'm zzzz but...3 phase mcb?...

fail....

 

[Guest 004]

^ ok buddy were are here to help people, not to dis

 

[D Skelton]

Forgive my rather rudimentary drawing but this is essentially what you want to do:

 

[Guest 004]

^ thanks DS

but I do think my OP has been awerserd by post no. 8

thanks guys


Can we let this run for a couple of of days, before a mod closes it down (happy with that), but pretty sure I have a good answer.

Thanks again hawk

 

[D Skelton]

Essentially, in its simplest form my drawing is what a phase faliure relay does

You don't neccessarily need a phase faliure relay so I'd go with whichever option is cheapest.

 

[Engineer54]

From the OP i'm still not sure what he's trying to do. If all he wants to do is shut down a 3 phase supply when losing a phase, say due to a fault down stream, and the supply has fuse over current protective devices, then all that's required is to replace the fuses with a multi phase MCB/MCCB. Anyway if he's happy that he's found a solution in the way of a phase failure relay, all's good!! lol!!


One of the reasons i don't like fuse protection for poly phase motors, unless those fuses are of the striker release type, where when any fuse ruptures, is releases a striker to disconnect all the phases.