Best Answer
Single phaseThe main advantage of 3 phase is that it is more efficient for running AC motors than one or two phase. Three phase was designed to be used for creating a rotating magnetic field in the motor, which starts rotation of the motor. Household service originally was intended for lighting and heating, while 3 phase was intended for industrial and commercial with large motors.

In US residential single phase service you have two hots, in phase with each other.

  • Vhot1(t) = Vmax * sin(2 * pi * freq * t)
  • Vhot2(t) = Vmax * sin(2 * pi * freq * t + pi)
  • Vmax equals the maximum voltage to neutral. (Approx. 170V (120V * sqrt(2)) for US residential service)
  • freq is the frequency of the line in Hz (60 for US residential service)
  • t is the time in seconds
  • Between either hot and neutral you have 120Vrms to neutral.
  • Between the two hots (Vhot1(t) - Vhot2(t)) you have 240Vrms
  • The voltage goes to 0V 120 times a second, no matter what wiring you choose.
  • You cannot get 3 phase from single phase without a special converter.
3 phase

In a 3 phase system you have 3 hots, out of phase with each other.

  • Vhot1(t) = Vmax * sin(2 * pi * freq * t)
  • Vhot2(t) = Vmax * sin(2 * pi * freq * t + 2 * pi / 3)
  • Vhot3(t) = Vmax * sin(2 * pi * freq * t + 4 * pi / 3)
  • Vmax equals the maximum voltage to neutral. (Approx 170V (120V * sqrt(2)) for 120/208V 3 phase)
  • freq is the frequency of the line in Hz (60 for US service)
  • t is the time in seconds
  • Between any hot and neutral you have 120Vrms to neutral. Since you are only using two conductors in this circuit, it is identical to 120Vrms single phase above. It can be used to power the same equipment that would be used on 120Vrms single phase power.
  • Between any two hots you have 208Vrms. Again, this is the same as above, though the voltage is less than single phase due to the phase shift. This can be used like 240V single phase above, if the load will tolerate the slightly lower voltage.
  • For heavy loads, all 3 hots can be used. Unlike single phase, one of the hots is always energized. The load will always have at least 140V (off a 208Vrms supply) between two hots. This makes it valuable for motors, as there is always a magnetic field present to pull the armature.
  • You can easily get single phase power from 3 phase with no converters.
  • 120/208V 3 phase service has 1.5 times the power capacity of equally rated 120/240V single phase.

From Wikipedia:

  • A three-phase motor will be more compact and less costly than a single-phase motor of the same voltage class and rating
  • Single-phase AC motors above 10 HP (7.5 kW) are uncommon
  • Three phase motors will also vibrate less and hence last longer than single phase motor of the same power used under the same conditions.
To sum up
  • Single phase is used in residential service. The split phase is used to power large loads that are too large to run off 120V. Otherwise, 120V single phase is used.
  • US consumer appliances are single phase, so there is no incentive to run 3 phase to homes.
  • 3 phase is usually only used in industrial settings with heavy equipment or motorized tools
  • Unlike residential service which is always 120/240V, industrial 3 phase can be much higher, with 480V not uncommon. The designer of the building is expected to design the electrical system for the use of the building. It is not uncommon for these building to have their own step-down transformer to 120/208V for lower voltage loads.
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Q: What is the advantage of a three phase power supply to a single phase power supply?
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Related Questions

How do you convert a three phase power supply into single phase power supply?

Any two legs of a three phase supply are classed as single phase. L1 - L2, L2 - L3 and L3 - L1.

How do you get three phase power from single phase service?

Use a 3 phase inverter that works off a single phase supply

When would a three phase supply be preferred over a single phase supply?

Bcoz in single phase if supply is interrupt or any trouble there is no power .but in 3 phase if 1phase supply gone we can manage it by other 2 phases

What is a single-phase?

Single-phase is used to describe a simple AC power supply on two wires called a line and a neutral. It distinguishes the supply from a three-phase supply using three or four wires, which is common in electric power distribution.

How do you wire a three phase motor with two speed to a single phase power supply?

A three phase motor requires a three phase power supply. You can not run a three phase motor on a single phase power supply unless you provide some kind of converter, such as a motor-generator set or an inverter. You might be able to get the motor to rotate on single phase, if you provide starting torque somehow, but you will not get rated power in that configuration.

How do you start a three phase motor to a single phase power supply?

You don't. A three phase motor will not start unless it is connected to a three phase supply.

Can you convert a single phase power supply into a three phase stabiliser to power a home?

Houses generally run on single phase power. It would not make sense to convert single phase to three phase to run a house. Please restate the question.

What is a static converter?

A static converter allows a single phase supply to operate a three phase motor. Basically it converts the single phase supply into enough energy to power the three phase motor.

What Difference between a single-phase power supply and a 3-phase power supply?

A single phase power supply has two "hot" legs or conductors which have a sine wave that are 180 degrees apart. A three phase power supply has three "hot" conductors which have a sine wave that are 120 degrees apart. You can thank Nicoli Tesla, whose birthday is today for the three phase or polyphase power supply and of course all alternating current!

Is 10 kva supply to 3 phase load is equal to 10kva supply to single phase load?

Yes of course!! 10 kva electrical power is 10 kva electrical power either it would be three phase or single phase. But other factors i.e. current, voltage changes accordingly. Actually this question is quit confusable. Because in 3phase system, if each phase gives 10kva power (single phase power = 10 kva) then 3 phase power will be 10 X 3 = 30 Kva If we go leteratualy towasrds the question, then the asnwer will be - No. becasue 10 kva supply to 3 phase load will be 3phase supply(i.e440V) & 10kva supply to single phase load will be single supply (i.e 250V).

What is the difference single phase and three phase supply system?

A 3-phase system can generally supply more power than single phase. Most ordinary houses have a single-phase supply while larger buildings like factories have 3 phase. In Europe a normal domestic supply has a single phase supply carried on two wires, a live and a neutral. For a large house or shop with a three-phase supply there is a 4-wire supply with three live wires and a neutral, and in principle it can supply three times the power (assuming the same wire size). So three times the power is supplied with four wires instead of two, and there is a saving in wire. A three-phase supply has a further advantage in that the current in the neutral tends to be low, and when the live wires happen to be carrying equal currents, the neutral current is zero. Thus the power lost in the resistance of the wire is reduced, and three-phase three-wire transmission is used all over the world for power transmission ove distances.

How do you calculate power in single phase?

In a single-phase system, power (expressed in watts) is generally called 'true power' or 'active power', and is the product of the supply voltage, load current, and load power factor.

Can you get a 3 phase supply from single phase and how?

No, you cannot get a three phase supply directly from a single phase supply. Nowadays electronic inverter units can be bought that will do the job. For very low power loads the cost of such invertors is quite reasonable but for high power loads they are very expensive. For high-power industrial uses the most economical solution is to have a 3-phase service installed by the local electric power utility company.

Does a transformer play a vital role in connecting a three phase motor to a single phase power supply?

To do this, you will need to phase shift the single phase power supply into three distinct phases that are 120 degrees out of sync with each other. Phase shifting transformers can be used for this, but there might be other ways as well.

What is the advantages of a three phase system over the single phase system?

The 3 phase system has an advantage for the single phase system for sure, the 3 phase system has more power than the single phase system, such that p=3vicos(theta).

What is static converter can a power supply of computer is static converter?

A single phase supply can operate a three phase motor with a static converter. No a power supply of computer cannot be fed through the static converter.

What are the uses of three phase transformer over single phase and their losses?

For a given load, a three-phase system requires around 75% of the volume of copper required by a corresponding single-phase system and, so, is more economical. A three-phase supply also delivers power more or less continuously, whereas a single-phase supply delivers power in pulses. Finally, three-phase motors are self-starting and physically smaller than single-phase machines of the same power rating.

Which A motor is to be operated from 230 V 50 HZ single phase AC?

All types of motor can be run from a single-phase supply provided the frequency, voltage and power capacity of the supply matches that of the motor and it has been designed to run on single-phase.

How do you get an equivalent three phases power from a single phase?

You cannot obtain a three-phase supply from a single-phase system without using some sort of rotary converter.

What are the advantages of using three phase to single phase motors?

Using three-phase or singe-phase motors depends mainly on what type of electric power supply is available. Most small properties have a single-phase supply of up to about 24 kW (100 amps). Properties requiring more power can be supplied with a second phase from a three-phase neighborhood supply, or in some cases a full three-phase supply. Three-phase is required for motors of over 30-40 HP, while most small motors up to 5 HP are single-phase.

Will a single phase appliance plugged into a 3 phase supply trip the supply if there is a problem?

If you plug a single phase appliance into a three phase power supply, then you will be using single phase power. It does not matter if you are delta connected, AB, BC, or CA, or if you are wye connected, AN, BN, or CN. Yes, if there was "a problem", you would trip the supply. Question, however, is what do you define as "a problem"? Three phase power is intended to supply three phase appliances. Connecting a single phase appliance to three phase power is inconsistent with the objective, and such connection must have been performed by some kind of "jury-rigging". If you pull more than the trip current on any one phase, the supply should trip. If a malfunction in the single phase application, however, were to result in fault current that is lower than the trip current, you might not trip, and you might create damage and/or a fire. There is nothing wrong with building a branch circuit that feed a single phase load from one phase of a three phase source. You just need to provide the correct protection for that intended load.

Why a fuse is fitted in the neutral of single phase domestic power supply?

A fuse is NOT fitted in the neutral phase of single phase domestic power supply. The fuse is fitted in the LINE (also mistakenly called Live). If you have checked and found that the fuse is in the neutral, something is wrongly wired.

Can you use three phase power for a dwelling unit service?

noAnswerWhereas most countries have single-phase residential supplies, some countries, such as Cyprus, often have three-phase supplies. The main distribution panel ('consumer unit') must be designed and assembled to accommodate either a single-phase supply or a three-phase supply; you cannot use a single-phase distribution panel with a three-phase supply.

Is Power in single phase equal to power in three phase?

No, it is 1.73 times more than single phase.Single phase formula, kW = I x E x pf/1000Three phase formula, kW = I x E x 1.73 x pf/1000Further AnswerThe power 'supplied' by any system is dependent upon the load, not the supply or the configuration of the supply. So the simple answer is that 'it depends' entirely on the load. However, the load capacity of a three-phase system is greater than that of single-phase supply providing the same load current.

Disadvantage of a three phase power supply to a single phase power supply?

There is no particular disadvantage to having a residential three-phase supply; in fact, such supplies are quite common in some European countries, such as here in Cyprus. There is absolutely no need to obtain special appliances, as ordinary single-phase appliances can be easily connected to a three-phase supply: they are simply connected between line and neutral (230 V in Europe). .