How can you get 230v single phase from 240v single phase supply?

Answer 1

Most modern homes have 240 Volts supplied. The 240 volts are measured between the two main busbars in the electric panel. The way the panel is organized you just need a 240 breaker that spans both busbars. They are double the height of a 120 V breaker. If you have an electric dryer, stove or whole house air conditioner you are likely already using 240 V. If for some strange reason you don't already have 240 V then you would need a transformer rated to your intended use.

Answer 2

240 volt three phase comes from primary distribution main line, usually 13.2 KV three phase, but different for different regions and countries, stepped down with Transformers. There are several possible configurations...

You can use three 13.2 KV to 240 V transformers wired in wye-wye, providing 240 phase to neutral and 277 phase to phase.

You can use three 13.2 KV to 240 V transformers wired in wye-delta, providing 240 phase to phase. This is an older configuration, saving the fourth transformer. Sometimes, one of the phases is centertapped, providing 120/240 split phase, and the neutral is off-center. In this case, the high side is 208 - opposite phase to neutral. In light industrial loads, you can actually use just two transformers to get the three phases, but total power will be imbalanced.

More commonly, in large industrial loads, you can use three 13.2 KV to 480 V transformers wired in wye-wye, providing 480 phase to neutral, and you use more transformers to get down to 240.

In even bigger industrial loads, you can use three 13.2 KV to 4160 V transformers into a switchgear room, providing secondary and tertiary transformers for whatever you want.

Answer 3

used only the two line of a 3-phase system. ex. used line 1 and line 2 only, or line 2 and line 3 or line 3 and line 1 to have a 240v single phase.

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The above answer has the question backwards.

No, you can not obtain three phase supply from a single phase supply with out spending a bit of money. If you are asking this to make a motor connection then that can be done. Depending on the amount of money you want to spend to make this happen there is a device on the market called a VFD ( Variable Frequency Drive). On the three phase input terminals you apply your single phase voltage. On the output terminals you connect your three phase motor. When run in this configuration there is an internal switch that has to be changed to let the VFD know that it should be looking for only two lines on the input to be hot. Other wise the VFD thinks that there is a line loss on the three phase input terminals and the unit will not start.

Answer 4

you use a double pole breaker.