i have a project title is single phasing preventer

abstract:
three-phase motors and other appliances are widely used in all sectors of industry. These appliances are prone to damage to single phasing. Apart from damage the costly apparatus, it may also cause a production loss. The objective of this project is to design a single phase preventer to be used in lab. This circuit is meant for the 3 phase 1KW induction motor.

actually i found a circuit, anyone can tell me this circuit can i use for the project? what should i change in this circuit?

I don't get how the electronics are supposed to help on this one.

A relay set-up is the easiest and cheapest way.

TT

Probably easier to use a phase imbalance detection relay e.g.
http://www.hobut.co.uk/protection-relays/phase-balance-protection-relay

Your circuit will work, with reservations, there may be sufficient regeneration in an inductive load which may render the detection of a phase loss doubtful using voltage alone - It would be better to monitor the phase currents instead (as commercial units mostly do).
In your circuit, putting the outputs from the three Transformers in series like that should give a resultant of zero with 3 balanced phases. i.e. 3 phases @ 120 degrees apart. If a phase is lost, then there should be (if regeneration does not take place) a resultant voltage at the AC terminals of the bridge rectifier. The 220Uf cap will smooth the DC and give a very small delay. The diode is purely back-emf protection. For a longer delay in operation increase the capacitor to say 1000Uf

Taking into account the cost of the transformers, a relay would probably be a viable option. But, if it is for a lab project, and you have to build it yourself, then go ahead and try it!