Power factor monitor in 3phase motor - current transformer

What current transformer should I choose to support a current of 15.9A at 400VAC (3phase - I leave in Portugal and F-N it´s 230VAC). The current transformer with ratio 1:1000 that´s oK? You said that I had to do the same circuit in each phase (I supposed that) but I only need one current transformer, that´s right?!
In each comparator I have to supply them with current and voltage... The current we use current transformer and the voltage we supply directly,passing by resistances, the Amp-Ops?
Just one more question... and if we haven´t Neutro (just 3phase) how we connect the circuit?
Thank´s!
Regards