 This video here is going to describe how we determine what our primary current is especially in a three-wire circuit So you notice here. We've got a line one up top You've got a line two at the bottom and then we have this neutral Which means that there's a chance that we're going to have an unbalanced load across this winding Different current then we're going to have across this winding and then the neutral is going to take the unbalanced load That's been covered in previous lessons now what this video is going to show is how can we take these currents and If they're different and figure out what our primary current is and there is such a super easy way It's redonkulous the easiest way to determine that is remembering the rule that kba in Whatever this guy is is kba out, which is this side here Which means to say that whatever this side of the transformer is asking for this side here has to give Which means that my power in is power out power is my friend So all we have to do to get this primary current on this side Why don't we just add 8 plus 3 plus 20 plus 15 and find out what this side of the transformer is asking for? Which works out to be 46 kilowatts, so at this time right now this transformer The secondary side is wanting to use 46 kilowatts Which means that this side is wanting to use 46 kilowatts and this side here has to give 46 kilowatts And now to determine what our current is all we have to do is take 46 kilowatts divided by 480 volts And we will get our primary current which is 95.8 amps that's it that's all that's done So remember all you have to remember with these things is that whatever the power is on the secondary side All this power here is going to be the same power being given on the primary side So work out what the powers are Add them up Take them over to here take that power divided by the source voltage and that will give you the current on the secondary side Sorry That's it