# Three phase supply

1. Jan 3, 2015

### ranju

we talk about three phase supply .. I want to know that what actually is three phase..?? Its obvious there are three wires carrying current but what is "phase" ?
Is there something like, transmission line is further divided into three wires ..?? Please explain..its quite basic.. and I am confused..!!

2. Jan 3, 2015

### phinds

You are right that it is quite basic and a simple Google search should turn up a good explanation with diagrams. Basically, it means exactly what it says ... there are three phases of voltages supplied, 120 degrees from each other.

3. Jan 3, 2015

### ande

the article above should help.

4. Jan 3, 2015

5. Jan 4, 2015

### n.karthick

The phase means the angular difference between the sinusoidal voltage on one wire to another. For three phase, the angular difference would be 360/3 = 120 deg. Instead of having three independent single phase transmission system which require (phase + neutral wire for each phase) 2*3 = 6 wires, if we go for three phase system with angular displacement of 120 deg we need only (1 wire for each phase and 1 common neutral) 3+1 = 4 wires for the same power transmission.