Timeline for Why is North American residential power called single phase?
Current License: CC BY-SA 4.0
8 events
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| Mar 18, 2022 at 3:54 | comment | added | user57037 | @richard1941 if you are replying to Limer you may want to insert a tag: (at) Limer. EESE doesn't automatically notify people in the comment section just because they also made comments. It did automatically notify me because you posted a comment under my answer. | |
| Mar 18, 2022 at 3:29 | comment | added | richard1941 | Well, if there is only one phase, why not just connect 'em and see what happens? | |
| Mar 13, 2022 at 18:09 | comment | added | Limer |
now you're kinda contradicting yourself. If one sees both L1 and L2 just as hot wires and 180° out of phase then V between L1 and L2 would be 0 because the out of phase waves would just cancel each other out. If, on the other hand, one measures the potential difference on one single scale between L1 and GND & L2 and GND with (GND at 0V) you'd have +120V and -120V (or vice versa). Now those two Ls are the inverse of each other *-1 (==180° out of phase) because sin(x)-sin(x+pi) = 2sin(x) = sin(x) + sin(x)
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| Mar 13, 2022 at 18:05 | history | edited | user57037 | CC BY-SA 4.0 |
added 5 characters in body
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| Mar 13, 2022 at 17:36 | comment | added | Limer |
Well okay, if you think of L1 as +120V AC and L2 as -120V AC (which makes no sense because it's AC) then they'd need to be 180° out of phase to get 240V -> sin(x) - sin(x+pi) = 2* sin(x). But that is a kinda wrong way too look at it because as stated in my answer one core can only transform one phase. Measuring from GND to L1/L2 kinda leads to that view but look at it like that: (GND+L1) + (GND-L2) and suddenly they are in phase. Eg. you need to measure from L2 to GND and from GND to L1 and they are in phase.
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| Mar 13, 2022 at 17:14 | comment | added | Limer | The question is primarily why the term "split phase" 'descibes' a single phase and not a two phase system. The reason why it is a single phases system is technical and exactly the reason why it can not be considered a two phase system and there is no phase shift of 180° between a split-phase L1 and L2. They're exactly in phase, otherwise you wouldn't get 240Vrms but less between L1 & L2 (180° out of phase and it would be 0V). -- Please read my answer electronics.stackexchange.com/a/611853/207587 | |
| Mar 13, 2022 at 14:38 | comment | added | Limer |
Split phase power is created by the center tap on the transformer secondary I strongly disagree. Split phase is just a non-technical term used instead of a physically/electrically correct one, eg. center taped single-phase. -- actual power inside residence & at service entrance could be called two phase No! In an AC n-phase system with n>1 the different phases need to be out of phase to each other, otherwise they wouldn't be different phases.
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| Mar 12, 2022 at 18:45 | history | answered | user57037 | CC BY-SA 4.0 |