2007-01-12 02:32:34 · 8 answers · asked by Juicy Lucy 2 in Science & Mathematics ➔ Engineering
single phase uses 2 wires and provides power
3 phase can use 4 wires. and provides 3 x power.
voltages are generated by rotating a shaft having a magnetic field which circulates within a series of coils. the generated voltages are in the form of a sine wave due to trigonometry see below.
because 3 phase transmission is quite efficient due to the above and the ease with which the voltages in ac can be stepped up and stepped down (by using transformers) it has become the accepted norm.
if you picture a circle turning and plot a fixed point on the circuit.
if you rotate the circle at 15 degree intervals (full circle is 360 degrees) and record the distance from the centre of the circle to a point level with the fixed points height with each rotation you will develope a sine wave. (hope this makes sense)
3 phase involves 3 of these points equaly spaced around the circle. they are said to be 120 degrees out of phase.
this is because the coils in the fixed windings of the generator are physically wired so as to be 120 degrees out of phase.
three phase systems can have four conductors L1, L2,L3, N and provide 400v between L's and 230V between L and N
a single phase supply is just L and N 230V
2007-01-13 22:01:08 · answer #1 · answered by Mark G 2 · 1⤊ 0⤋
Very basically. The substation supplies, via a three phase transformer, mains voltage to three rows of houses. Each row takes one phase and neutral (single phase UK 240v 50Hz). The neutral, in this case, takes the unbalanced load (current) back to the star point earth. There are many different uses and applications for three phase power/systems. If you want to get a better understanding have a look on the web there are a number of very good articles.
For clarity: if you measure between one phase and neutral you will read (UK) 240v (as in your house). If you measure between phases you will read 415v (240*sqrt3).
Now you're totally confused I'll leave it at that.
2007-01-12 09:01:11 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Three phase is usually used by industrial consumers, it is three cables and there is a voltage difference among the three, you can use three cables one at a time closing the circuit with ground, that is a single phase, or the three connected to ma electric motor for instance
2007-01-12 02:40:42 · answer #3 · answered by runlolarun 4 · 0⤊ 1⤋
Single phase is one sinusoids compared to neutral (neutral usually connected to ground).
Three phase is three sinusoids each phased by 120 degrees. The vectorial sum of these is 0v. So three phase signal can travel through 3 wires. Phase to phase voltage is sqrt(3) time phase to neutral voltage.
2007-01-12 03:16:42 · answer #4 · answered by catarthur 6 · 1⤊ 0⤋
Single phase is electric which comes on instantly. It is like switching on an electric motor and it is running at top speed right away. Three phase is an electric motor that goes through phases to get to full speed. Three phase motora usually drive big equipment and they have to get up to speed gradually.
2007-01-12 02:41:55 · answer #5 · answered by Anonymous · 0⤊ 2⤋
well single phase has only one output, while 3 phase has 3 outputs each producing the same power( so 3 phase produces 3 times the single phase).
it like a wheel with 3 arms rotating and each has a coresponding contact.
2007-01-12 02:43:13 · answer #6 · answered by D 3 · 0⤊ 2⤋
Single phase = one hot wire and one ground wire. In America it is called 110v.
Three phase = 2 hot wires and one ground wire called 220v.
2007-01-12 02:43:35 · answer #7 · answered by Anonymous · 0⤊ 1⤋