Why is 3 phase more efficient?

Answer 1

There are a few reasons. In my opinion the most common is cost. In an industrial setting, three phase power is used to power motor loads. A three phase induction motor is more efficient than a single/split phase motor. They also have higher starting torque. A three phase load will also typically have a lower amp rating for the same size load as single phase. This saves money because you can use smaller wire.

Answer 2

Three phase systems are used because they are the best balance of cost and amount of power flow. Three phase systems provide stability for transmitting smoother power. There could be a higher number of poly phase systems but the cost more to implement without giving the benefit of an equal amount of extra power flow.

Three Phase power systems are used because the current is less per phase than what would be needed in a single phase system. Because the current is lower the size of the wire is also smaller which makes the cost of installation and maintenance lower. Other than that the cost is the same. Watts (Power) is power regardless of the type of system. An example would be a 10 HP motor which uses 7460 watts of power. On a 220v single phase system the motor would pull almost 34 amps. On a 230v 3 phase system it would pull about 20 amps. On a 3 phase motor circuit you could use a number 12 wire on a 30 amp breaker. On the single phase system you would have to use about a number 6 wire with a 50 amp breaker. Two number 6 wires cost a lot more than 3 # 12's. The conduit size may have to be increased to 3/4" where as the 3# 12's could be in a 1/2".

Answer 3

Three phase systems at the same voltage potential in relation to earth as the single phase system are capable of supplying more power, approximately 1.732 times more, than the single phase system. Three phase equipment, especially electric motors, are smaller and more compact than single phase equipment. It is also cheaper to transmit electrical energy over long distances with three phase than it is with single phase. There are many more advatages of using three phase over single phase.

Answer 4

With 3 phase power, you can deliver 3 x the power of single phase with 50% more wire. This means it's cheaper to transport 3 phase power as opposed to single phase. There are other reasons when it comes to generating power as well - pulsing stresses on a generator will be less with 3 phase vs. single phase generation, for example.

Answer 5

The use of 3 phase systems is ideal as it produces a rotating magnetic field, which allows more basic motor design.

Answer 6

Three phase is used in transmission/distribution systems because it is more economical, in terms of the amount of copper used, than single phase for a given load.