Three phase power supply

[pvd]

I want to design a circuit for avoiding the single phasing in the three phase power supply. Means when any phase is missing in the supply then the power supply should be shut down. Please reply fast. Urgent...

 

[pvd]

hiiiiiiiiiiiiii

 

[Ubergeek63]

you actually do not give anywhere near enough info for anyone to help you and most here are not up to it. are you coming of the three outputs of a 3PH transformer?

 

[tcmtech]

Just use a relay on each phase with the contacts wired in series so that if one phase shuts down that relay opens its contacts ans shuts off what ever primary power system to what ever it is that you are controling.

But yes, far more information would be much more helpful.
System voltage, amps, what is it controlling, and what is being powered.

 

[crutschow]

You could also put an optocoupler across each phase. Use a rectifier, resistor, capacitor filter to generate the required turn-on current for each coupler's input from each phase's voltage. Monitor the optocoupler outputs with a 3-input AND/(NAND) gate. If any phase drops out the gate's output will go low (high).

(If the optocouplers are the type with a transistor output, then you could place all transistors in series to give a wired AND function. The string of transistors will stop conducting if any phase drops out.)

 

[mbarazeen]

use two undervoltage relays between two different phases and wire the control power of the contactor of the power supply, through its normally open contacts. when there is a missign phase one relay will open and the contactor will cut off the power

 

[mbarazeen]

use two undervoltage relays between two different phases and wire the control power of the contactor of the power supply, through its normally open contacts. when there is a missign phase one relay will open and the contactor will cut off the power