Star/Delta

[Mark.W]

Hi

Could someone please help me out here I am going insane.

In say a Delta connection, why is Line Voltage = Phase Voltage but Line Current = Phase Current x square root of 3, why isn't line voltage = phase voltage x square root of 3. and vice versa for a star connection.
Basically why in a delta connection is only the phase current multiplied but the square root of 3 and not phase voltage.

I hope that makes sense

Many Thanks
Mark

 

[Darkwood]

In a balanced star connection IL( line current) is the same as Ip (current phase or load) as all three phases meet at the center you get a 0V point to test across the load(230v across load) but in a delta there is no 0v point and testing across a load is 400v so extra calcs is needed to work this out.
Hope i explained ok

Good book to get is 'Electrical Installation calculations' by A.J. watkins and C. kitcher (Newnes) as it has it explains with diagrams as well.

 

[Steve1412]

There are some great instructional vids on this link if you guys want a blast to the past college work etc.They are based in india but all things are equal.
NPTEL Courses