Difference Between Single Phase & Three Phase

The power supply system is mainly classified into two types, i.e., single phase and the three phase system. The single phase is used in a place where less power is required and for running the small loads. The three phases are used in large industries, factories and in the manufacturing unit where a large amount of power is required.

One of the major difference between the single phase and the three phase is that the single phase consists one conductor and one neutral wire whereas the three phase supply uses three conductors and one neutral wire for completing the circuit. Some other differences between them are explained below in the comparison chart.

Comparison Chart: Single Phase V/S Three Phase


Basis For ComparisonSingle PhaseThree Phase
DefinitionThe power supply through one conductor.The power supply through three conductors.
Wave Shapewave-shape-1wave-shape-2
Number of wire.Require two wires for completing the circuit. Requires four wires for completing the circuit.
VoltageCarry 230VCarry 415V
Phase NameSplit phaseNo other name
Power Transfer CapabilityMinimumMaximum
NetworkSimpleComplicated
Power FailureOccursDo not occur
LossMaximumMinimum
Power Supply Connectionpower-connection-1power-supply-connection-2
EfficiencyLessHigh
EconomicalLessMore
UsesFor home appliances.In large industries and for running heavy loads.

Definition of Single phase

The single phase requires two wires for completing the circuit, i.e., the conductor and the neutral. The conductor carries the current and the neutral is the return path of the current. The single phase supplies the voltage up to 230 volts. It is mostly used for running the small appliances like a fan, cooler, grinder, heater, etc.

single-phase-supply

Definition of Three Phase

The three phase system consist four wires, three conductors and one neutral. The conductors are out of phase and space 120º apart from each other. The three phase system is also used as a single phase system. For the low load, one phase and neutral can be taken from the three phase supply.

three-phase-supply

The three phase supply is continuous and never completely drops to zero. In three phase system power can be drawn either in a star or delta configuration. The star connection is used for long distance transmission because it has neutral for the fault current.

star-connection

The delta connection consists three phase wires and no neutral.

delta-connection

Key Differences Between Single Phase and Three Phase

  1. In single phase supply, the power flows through one conductor whereas the three phase supply consists three conductors for power supply.
  2. The single phase supply requires two wires (one phase and one neutral) for completing the circuit. The three phase requires three phase wires and one neutral wire for completing the circuit.
  3. The single phase supplies the voltage up to 230V whereas the three phase supply carries the voltage up to 415V.
  4. The maximum power is transferred through three phases as compared to single phase supply.
  5. The single phase has two wire which makes the network simple whereas the three phase network is complicated as it consists four wires.
  6. The single phase system has only one phase wire, and if the fault occurs on the network, then the power supply completely fails. But in three phase system the network has three phases, and if the fault occurs on any one of the phases, the other two will continuously supply the power.
  7. The efficiency of the single phase supply is less as compared to three phase supply. Because the three phase supply requires less conductor as compared to single phase supply for the equivalent circuit.
  8. The single phase supply requires more maintenance and become costly as compared to three phase supply.
  9. The single phase supply is mostly used in the house and for running the small loads. The three phase supply is used in large industries and for running the heavy loads.

The star connection of the three phase allows the use of two different voltages (i.e., the 230 volts and the 415 volts). The 230V is supplied by using the one phase and one neutral wire, and the three phase is supply between any two phases.

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