3-phase ac is commonly used for transmission over several hundred kilometres within a synchronous grid system.
DC is used for longer distances or for connection between two systems which are not in synchronism.
Yes, there is a difference between single phase and three phase circuits.
There is no such thing as a two phase instrument. There is only single phase and three phase. You can only have: single phase/ one pole single phase/ two pole three phase/ three pole
single phase, double phase & three phase
No A intermediate switch can not be used to change three phase to single phase.
Single phase.
I think you mean 'single-phase supply', rather than 'phase supply'. All high-voltage a.c. transmission and distribution systems are three-phase systems. This is because, for a given load, a three-phase system uses less copper than a single-phase system. Three-phase generators produce three 'phase voltages', each displaced, by 120 electrical degrees. These voltages are produced in three windings which are electrically connected in what is called a 'delta' configuration, with each 'corner' of the delta connected to the transmission system by 'line' conductors. Three-phase systems are either 'three-wire' or 'four-wire' systems. Generally, three-phase, three-wire, systems are used for high-voltage transmission and distribution, whereas three-phase, four-wire, systems are typically (but not always) used for low-voltage distribution. Three-wire systems comprise three conductors called 'line conductors'; four-wire systems comprise three 'line conductors' and a 'neutral conductor'. Depending the voltage standards used in the country in which you live, a single-phase supply is obtained either by connecting single-phase load between any two line conductors, or between any one line conductor and the neutral conductor.
The difference between a single phase and a three phase motor is the amount of power conductors that feed the device. As to the other part of the question a three phase motor will not start or run on single phase. The phase angles on three phase are 120 degrees apart on a single phase system they are 180 degrees apart.
Single phase inherently requires less equipment (it's cheaper). Three phase motors are more efficient than single phase.
Yes, there a difference between three phase and single phase electrical supply services.
A three-phase meter can be used for single phase while the reverse is not the case.
There is no need of single phase to three phase conversions. Both service types are available from the local utility company.
Most electrical equipment are either designed to work on Single phase (two wires) or Three Phase (three or four wires). Two phase equipment are non existent today. A single phase heater will require a single phase thermostat while a three phase heater will require a three phase thermostat.