Introduction to the Delta Wye transformer connection. Part 7b.
Okay there is one more thing we really need to note about the voltage across the primary winding and the voltage across the secondary winding.
Because the HV winding A and the LV winding a are magnetically coupled, we know that the voltage across the phase A winding will be in phase with the voltage across the secondary winding which we also defined as Vag. Okay so they are going to be in phase because the two windings are magnetically coupled.
But that doesn't mean that the magnitude of the HV winding is going to equal --- so it's not going to equal the magnitude of voltage on the LV winding. So the magnitudes will definitely differ. But whatever the magnitudes will be, they will be in phase. So that's one characteristic that we really need to understand.
Okay so before we explain that concept in this phasor diagram – if you haven't already, please click on the bottom right hand corner of the screen – there should be a subscribe button. Please subscribe to this channel.
Okay so here is open phasor diagram for the illustration that we did above. Now this illustration comes from the previous video tutorials, so if you haven't watched the previous video tutorials, this won't make very much sense.
What we're saying is that this phasor here – we've defined this phasor as the voltage across line A and line B. Which is equal to the voltage across winding A on the HV side. And what we've said was the LV side will have the same phase as this phasor but the magnitudes will be different.
So this orange here is an illustration of the LV winding. It's the same phase as V phase A, but the magnitude of it is smaller because it's a LV winding. So I'm going to define this as V phase a which is equal to Vag on the LV winding.
Similarly, we're going to represent the LV winding b and c in this phasor diagram. Okay so there you have it, this phasor here represents the voltage across the LV winding. And as you can see, it's in phase with the voltage across the HV winding for winding B. But the magnitude of it is obviously smaller.
The voltage across the LV winding for winding c is in phase with the voltage across the HV winding for winding C but the magnitude of the LV winding is smaller.
So that's how you represent the HV winding and the LV winding for the delta wye transformer connection.
This was a necessary step to understanding the phase shift. In part 7c, we're going to analyze how this transformer connection is defined formally like this and informally like this.
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