I can't find any resources online regarding what we are trying to do,
Basically we have a programmable controller (230VAC 1PH input) that is programmed to actuate the shunt trip coil of the main breaker (4 pole A,B,C,N) on a fault condition; but it also needs to remain powered incase of a phase loss (i e. if phase A goes it should be powered through B or C).
While the controller power is 1PH, our system input is 400VAC 3PH. By implementing a basic circuit using relays we were hoping to create contingency even when a phase goes missing. see attached.
The relay is a 400VAC rated relay with double pole (form-c). We did not use any timing relays, or any complex circuitry. When R1 is energized it will take precedence in powering the controller. When phase A is missing R1 will not energize, therefore R2 will take precedence. NOTE: all 3 relays do energize at the same time if all 3 phases are present. There is no induced voltage across the phases because there is a RFI filter at the 3 phase input.
We tested several times with the setup as shown in the attached but results are no good, intermittently we would have these relays pop (blow up essentially) and it appear to have shorted which maybe the result of the fact that our setup basically compromises switching delay on each relays.
Have any of you experts know anything about this? what could be an alternative solution to what we're trying to achieve? a 3-way redundant 1 phase power? is this even possible?
Thanks guys, been scratching my head too much!
Josh
Basically we have a programmable controller (230VAC 1PH input) that is programmed to actuate the shunt trip coil of the main breaker (4 pole A,B,C,N) on a fault condition; but it also needs to remain powered incase of a phase loss (i e. if phase A goes it should be powered through B or C).
While the controller power is 1PH, our system input is 400VAC 3PH. By implementing a basic circuit using relays we were hoping to create contingency even when a phase goes missing. see attached.
The relay is a 400VAC rated relay with double pole (form-c). We did not use any timing relays, or any complex circuitry. When R1 is energized it will take precedence in powering the controller. When phase A is missing R1 will not energize, therefore R2 will take precedence. NOTE: all 3 relays do energize at the same time if all 3 phases are present. There is no induced voltage across the phases because there is a RFI filter at the 3 phase input.
We tested several times with the setup as shown in the attached but results are no good, intermittently we would have these relays pop (blow up essentially) and it appear to have shorted which maybe the result of the fact that our setup basically compromises switching delay on each relays.
Have any of you experts know anything about this? what could be an alternative solution to what we're trying to achieve? a 3-way redundant 1 phase power? is this even possible?
Thanks guys, been scratching my head too much!
Josh
Attachments
-
172.3 KB Views: 18