Current flow in delta configuration

[kwired]

I was asking what the direction of current flow is inside the delta configuration. I wasn't sure if clockwise, counterclockwise, or if it flowed the same way as the line currents... 2 in one direction with the 3rd in the opposite direction.

It is alternating current and flows opposite direction every half cycle. You can look at the graphs in post 3 and see where the voltage driving the current is at for each phase at any point in time. For inductive loads the current will be lagging the voltage but all three will be lagging the same amount. You get rotation of magnetic fields in three phase motor because each winding reaches peak at a different time, interchanging any two supply leads will reverse the direction of that rotation. You would have similar thing going on in a transformer which will cause the phase relationship to be transferred from primary to secondary windings.

 

[Grouch1980]

and shifted in time by a partial cycle.

Cheers, Wayne

Is the shift in time = π / 3? I'm looking at the 2 graphs by Carultch in Post #3

 

[wwhitney]

Is the shift in time = π / 3? I'm looking at the 2 graphs by Carultch in Post #3

Precisely. If the 3 coil currents are equal in magnitude and at phase shifts of 0, 120, and 240 degrees, then the 3 line currents will be at phase shifts of 60, 180, and 300 degrees.

Cheers, Wayne

 

[wwhitney]

Is the shift in time = π / 3? I'm looking at the 2 graphs by Carultch in Post #3

P.S. Depending on your interest level in the math and/or vectors, see this thread for a semi-practical application:

Currents on 3ph 4w Delta panel Question

As mentioned, 3ph 4w, B leg is high. Assume the following fully resistive loads 100A 3ph 100A 1ph (A to Neutral) 50A 1ph (C to Neutral) Am I over simplifying thinking that the currents are as follows: Line A: 200A Line B: 100A Line C: 150A Or does some vector math need to come in here? If...

forums.mikeholt.com

Cheers, Wayne

 

[Grouch1980]

P.S. Depending on your interest level in the math and/or vectors, see this thread for a semi-practical application:

Currents on 3ph 4w Delta panel Question

As mentioned, 3ph 4w, B leg is high. Assume the following fully resistive loads 100A 3ph 100A 1ph (A to Neutral) 50A 1ph (C to Neutral) Am I over simplifying thinking that the currents are as follows: Line A: 200A Line B: 100A Line C: 150A Or does some vector math need to come in here? If...

forums.mikeholt.com

Cheers, Wayne

Thanks! I'll check it out.