Need Basic 3-Φ Transformer voltages

[abicash]

Hello
This is somewhat basic but i need to know voltages for the following
(Attached in image)

1)Require 220VDC-65 Amp as o/p voltage
2)Input is a 3Φ-Star and Output is 3Φ-Star Transformer respectively.On the secondary side i won't use the Neutral.
3)Secondary is fed to a diode rectifier without a filter capacitor or choke

What should be the voltages from RY,YB,BR and the current rating for each phase.

Please respond since my 3Φ principles are a bit rusty...

Thanks and regards

 

[mvs sarma]

please go thro fundas of star delta transformers.
usage of star-star is very rare.
on primary side with neutral used you get 230V each phase and on secondary as you don't use nutral and if the turns ratio is same, you are getting 410V and NOT 230V tehn the recified voltage if filtered would be almost 1.414 (sq.root 2) times the AC secondary.

 

[abicash]

Hello and thank you for reading but i have the option of only STAR-STAR connection hence the difficulty in calculating values

Now for a 220VDC o/p i am doing this:

VDC = 220V
VR1Y1=VY1B1=VB1R1=? 

PHASE-to-PHASE=
VR1Y1=VY1B1=VB1R1=VDC/√2 = 220/√2 =156Vrms

OR 156Vrms/√3=(128Vpeak)90vrms across each phase-neutral (VR1N...)

Is this correct?

 

[abicash]

on primary side with neutral used you get 230V each phase and on secondary as you don't use nutral and if the turns ratio is same, you are getting 410V and NOT 230V tehn the recified voltage if filtered would be almost 1.414 (sq.root 2) times the AC secondary.

Hi mvs sarma , the purpose of this post was to find the turns ratio as to define the voltages for the secondary ..its not 1:1
Secondly i have mentioned in my original post that filter isnt present