How to have the neutral point from three phase motor terminals?

[yzou_ua]

My motor has general 3 phase stator terminals, but I want to measure the phase-to-neutral voltage (for some control purpose). How can I have the neutral point to do the measurement then??
Pls help!! Thx a lot!

 

[FvM]

There are basically two star points. The real star point of the supply network (the neutral wire) and the center of the three phase voltages which can be generated by a wye resistor network. Both coincide for a symmetrical loaded supply network.

 

[yzou_ua]

I got it.
Also, my ph-ph stator voltage is 220Vrms(311Vpeak), so I use 200K Ohm wye resistor with 1/2W. Such design is ok?? So, the less resistor curr., the better? Or any other thing should be paid attention in selecting wye resistor?
Thx a lot!

There are basically two star points. The real star point of the supply network (the neutral wire) and the center of the three phase voltages which can be generated by a wye resistor network. Both coincide for a symmetrical loaded supply network.

 

[FvM]

Input resistance of the measurement circuit and resistor power dissipation are the constraints, I think.