# The Naked Scientists Forum

### Author Topic: Why is 1.73 used in calculating 3 phase wattage?  (Read 11293 times)

#### tommya300

• Hero Member
• Posts: 655
##### Why is 1.73 used in calculating 3 phase wattage?
« on: 17/07/2010 01:17:09 »
3 phase electrical ... Watts = (V)(A) 1.73

Where did the 1.73 value come from? Why is it used?

#### Joe L. Ogan

• Sr. Member
• Posts: 476
##### Why is 1.73 used in calculating 3 phase wattage?
« Reply #1 on: 17/07/2010 02:19:45 »
Je ne sais pas!  Thanks for comments.  Joe L. Ogan

#### tommya300

• Hero Member
• Posts: 655
##### Why is 1.73 used in calculating 3 phase wattage?
« Reply #2 on: 17/07/2010 02:37:33 »
Je ne sais pas!  Thanks for comments.  Joe L. Ogan

ta mz quzwa?

#### Geezer

• Neilep Level Member
• Posts: 8328
• "Vive la résistance!"
##### Why is 1.73 used in calculating 3 phase wattage?
« Reply #3 on: 17/07/2010 05:37:22 »
It's because the voltage between the phases is 1.732 times the phase to neutral voltage.

The value can be derived from vector analysis. It boils down to 2cos30 which equals 1.732 (which also happens to be √3)

#### tommya300

• Hero Member
• Posts: 655
##### Why is 1.73 used in calculating 3 phase wattage?
« Reply #4 on: 17/07/2010 13:27:39 »
It's because the voltage between the phases is 1.732 times the phase to neutral voltage.

The value can be derived from vector analysis. It boils down to 2cos30 which equals 1.732 (which also happens to be √3)
Thanks Geezer

#### The Naked Scientists Forum

##### Why is 1.73 used in calculating 3 phase wattage?
« Reply #4 on: 17/07/2010 13:27:39 »