[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:02.37,Default,,0000,0000,0000,,>> Converting impedances from
Dialogue: 0,0:00:02.37,0:00:05.22,Default,,0000,0000,0000,,a delta connection to
Dialogue: 0,0:00:05.22,0:00:08.19,Default,,0000,0000,0000,,a Y connection or from a Y\Nconnection to a delta connection,
Dialogue: 0,0:00:08.19,0:00:13.10,Default,,0000,0000,0000,,is analogous to what we saw when we\Nwere dealing strictly with resistances.
Dialogue: 0,0:00:13.10,0:00:16.63,Default,,0000,0000,0000,,Again, what we mean when\Nwe say that one say that
Dialogue: 0,0:00:16.63,0:00:21.28,Default,,0000,0000,0000,,Y circuit is consistent or is\Nequivalent to a delta connection.
Dialogue: 0,0:00:21.28,0:00:25.54,Default,,0000,0000,0000,,By that, we mean that the impedance
Dialogue: 0,0:00:25.54,0:00:32.42,Default,,0000,0000,0000,,seen looking in between\Nany two terminals is the same,
Dialogue: 0,0:00:32.42,0:00:37.67,Default,,0000,0000,0000,,whether it is connected in Y or
Dialogue: 0,0:00:37.67,0:00:40.04,Default,,0000,0000,0000,,connected in delta and when you
Dialogue: 0,0:00:40.04,0:00:42.80,Default,,0000,0000,0000,,compare these with those that we saw\Nwith working with straight resistances,
Dialogue: 0,0:00:42.80,0:00:48.04,Default,,0000,0000,0000,,you'll see that\Nthe same relationships hold.
Dialogue: 0,0:00:48.04,0:00:53.11,Default,,0000,0000,0000,,On this side here we have the Y to
Dialogue: 0,0:00:53.11,0:00:56.57,Default,,0000,0000,0000,,delta connection and\Nhere we have converting
Dialogue: 0,0:00:56.57,0:01:00.86,Default,,0000,0000,0000,,delta connected load to a Y connected load.
Dialogue: 0,0:01:00.86,0:01:05.50,Default,,0000,0000,0000,,So, the Y connected load impedances\Nare Z_1, Z_2 and Z_3.
Dialogue: 0,0:01:05.50,0:01:09.20,Default,,0000,0000,0000,,The delta connected as Z_a, as Z_b and Z_c,
Dialogue: 0,0:01:09.20,0:01:14.32,Default,,0000,0000,0000,,where Z_1 is connected to node one,
Dialogue: 0,0:01:14.32,0:01:16.41,Default,,0000,0000,0000,,Z_2 is connected to node two,
Dialogue: 0,0:01:16.41,0:01:20.22,Default,,0000,0000,0000,,Z_3 is connected to node three and Z_a
Dialogue: 0,0:01:20.22,0:01:25.23,Default,,0000,0000,0000,,is the impedance opposite\Nthe number one terminal,
Dialogue: 0,0:01:25.23,0:01:28.90,Default,,0000,0000,0000,,Z_b is the impedance opposite\Nthe number two terminal
Dialogue: 0,0:01:28.90,0:01:34.44,Default,,0000,0000,0000,,and Z_c is the impedance\Nopposite the third terminal.
Dialogue: 0,0:01:34.44,0:01:36.72,Default,,0000,0000,0000,,Now, these become interesting,
Dialogue: 0,0:01:36.72,0:01:41.54,Default,,0000,0000,0000,,even more interesting than they\Nalready are and the circumstances when
Dialogue: 0,0:01:41.54,0:01:46.88,Default,,0000,0000,0000,,Z_1 equals Z_2 equals Z_3 or you\Ngot a balanced three-phase load.
Dialogue: 0,0:01:46.88,0:01:51.18,Default,,0000,0000,0000,,Under those circumstances, when Z_1
Dialogue: 0,0:01:51.18,0:01:56.94,Default,,0000,0000,0000,,equals Z_2 equals Z_3, we'll call that Z_y.
Dialogue: 0,0:01:56.94,0:01:59.47,Default,,0000,0000,0000,,When that is the case,
Dialogue: 0,0:01:59.47,0:02:06.74,Default,,0000,0000,0000,,then Z_a equals Z_b equals Z_c.
Dialogue: 0,0:02:06.74,0:02:11.97,Default,,0000,0000,0000,,We'll call that Z Delta is equal to.
Dialogue: 0,0:02:11.97,0:02:15.72,Default,,0000,0000,0000,,If this Z is the same, you have one, two,
Dialogue: 0,0:02:15.72,0:02:21.02,Default,,0000,0000,0000,,three, Z_y squared divided by Z_y.
Dialogue: 0,0:02:21.02,0:02:27.13,Default,,0000,0000,0000,,So, Z Delta then is equal\Nto three times Z_y,
Dialogue: 0,0:02:27.13,0:02:30.65,Default,,0000,0000,0000,,and over here you do\Na similar situation where
Dialogue: 0,0:02:30.65,0:02:35.77,Default,,0000,0000,0000,,Z_a equals Z_b equals Z_c equals,
Dialogue: 0,0:02:35.77,0:02:37.67,Default,,0000,0000,0000,,call that again Z delta,
Dialogue: 0,0:02:37.67,0:02:42.78,Default,,0000,0000,0000,,then Z_1 equals Z_2 equals Z_3,
Dialogue: 0,0:02:42.78,0:02:46.89,Default,,0000,0000,0000,,call that Z_y and that is then here
Dialogue: 0,0:02:46.89,0:02:51.52,Default,,0000,0000,0000,,you'd have Z Delta squared\Nover three Z delta,
Dialogue: 0,0:02:51.52,0:02:57.76,Default,,0000,0000,0000,,or Z_y then is equal to\NZ Delta divided by three.