Three Phase/ Four phase
- Thread starter Sucre
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Why are you interested in four phase?
FWIW, an old system called two-phase, and still in use in a few locations, had three different configurations: 3-, 4-, and 5-wire. The 4-wire was/is essentially two separate single phase 2-wire systems with one phase 90° (or 270°) out of phase to the other. The 3-wire system just made a common out of 2 wires of the 4-wire system. Getting to the point, the 5-wire system made a common of the midpoints of a 4-wire system. Though still classified as two phase, you essentially had/have four legs each 90° out of phase to the adjacent legs.
Technical information on two phase on the internet is limited, but it's there. You'll also want to research the Scott T transformer for converting 3Ø to 2Ø.
FWIW, an old system called two-phase, and still in use in a few locations, had three different configurations: 3-, 4-, and 5-wire. The 4-wire was/is essentially two separate single phase 2-wire systems with one phase 90° (or 270°) out of phase to the other. The 3-wire system just made a common out of 2 wires of the 4-wire system. Getting to the point, the 5-wire system made a common of the midpoints of a 4-wire system. Though still classified as two phase, you essentially had/have four legs each 90° out of phase to the adjacent legs.
Technical information on two phase on the internet is limited, but it's there. You'll also want to research the Scott T transformer for converting 3Ø to 2Ø.
kwired
Electron manager
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- NE Nebraska
Not that it would necessarily be something impossible but in general four phase systems are not standard distribution systems. There are three phase four wire systems, and two phase four wire systems that would be standard though. You sure you know the technicalities of exactly what you are trying to ask about?
Phil Corso
Senior Member
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- Boca Raton, Fl, USA
Sucre...
For a fixed amount of power there is no difference how many phases are used. However, when you take into account the weight, hence the cost, of the conductor material, then the 3-phase system is more economical than any other N-phase system!
To illustrate the above, a 3-phase system requires 3/4 of the weight of a single-phase system. For a 4-phase system the comparable ratio is also 3:4.
If you want additional info, and you can stand the math (trig is all that's needed) contact me... on or off forum!
Regards, Phil Corso
For a fixed amount of power there is no difference how many phases are used. However, when you take into account the weight, hence the cost, of the conductor material, then the 3-phase system is more economical than any other N-phase system!
To illustrate the above, a 3-phase system requires 3/4 of the weight of a single-phase system. For a 4-phase system the comparable ratio is also 3:4.
If you want additional info, and you can stand the math (trig is all that's needed) contact me... on or off forum!
Regards, Phil Corso
Tony S
Senior Member
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- Resting under the Major Oak UK
Look up Scott T and LeBlanc transformers. I’m working on an animation of a 4Ph motor at the moment, it’ll get finished one day.
mbrooke
Batteries Included
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- United States
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Can someone post graphics of the combos? And why not just use 3 wires rather then 5?
kwired
Electron manager
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- NE Nebraska
Are you asking about two phase?
drcampbell
Senior Member
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- The Motor City, Michigan USA
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- Registered Professional Engineer
Six-phase is frequently used when DC power is required. It provides better-quality DC (less ripple) with less or no filtering.
Tony S
Senior Member
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- Resting under the Major Oak UK
For low ripple rectification you can get 96Ph from a 3Ph supply but you have to remember only ½ of the opposed windings are in use at a time.
12Ph secondary: It shows the phase angles and current flow or have I got it mixed up with the story board for Custer’s Last Stand?
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
I like this video
Power Transmission Engineer Lionel Barthold Explains how 3 phase, 6 phase, and 12 phase power works, advantages, disavantages, and hopes for the future.
https://www.youtube.com/watch?v=HqZtptHnC2I
Power Transmission Engineer Lionel Barthold Explains how 3 phase, 6 phase, and 12 phase power works, advantages, disavantages, and hopes for the future.
https://www.youtube.com/watch?v=HqZtptHnC2I
zbang
Senior Member
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- Roughly 5346 miles from Earls Court
Some servo drive systems are called "four phase", could be what you're thinking of.
mbrooke
Batteries Included
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- United States
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3 vs. 5... each has its own merits.
Thanks!
A looks a bit redundant, can't you just combine two wires for a partial neutral? (partial in that its not perfect cancelling)- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
If you have two hots and a neutral (definitely a neutral under NEC definition) the neutral current will be 1.414 times the current in each hot. So it must be oversized.Thanks!
If you are talking about a 3-wire system, the common, though denoted as a neutral in the diagram I posted, under the current NEC definition I do not agree. A wire can only be a neutral conductor when connected to the system neutral point... and the common junction does not meet the criteria for such.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
The voltage to all of the rest of the circuit conductors is the same. So it is a neutral. It does not say that there have to be enough conductors to make the phase circle complete. JMO.
In a separate NEC section we find that it is a neutral which is still counted as a CCC since it is not one of the listed one or three phase configurations.
Tony S
Senior Member
- Location
- Resting under the Major Oak UK
In = 1/(√Ia²+Ib²)*100
Tony S
Senior Member
- Location
- Resting under the Major Oak UK
Neither of us are right, the resultant is the inverse of √Ia²+Ib²
In = 1/√Ia²+Ib²
...assuming pf 1.
In = 1/√Ia²+Ib²
...assuming pf 1.
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