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I am living in an area where line voltage is 220V. If I have access to all 3 phases, is it possible to create a "socket" with output voltage of ~110V, without use of a transformer? This is primarily a thought experiment, rather than a project with definite scope.

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    \$\begingroup\$ "using only those phases and maybe some simple components as caps or inductors" You mean like a transformer? \$\endgroup\$ – jippie Jan 3 '14 at 16:25
  • \$\begingroup\$ Nope, the whole point is not to use a transformer. I have no idea if it's possible. I am thinking maybe something like shifting one of the input's phases so that the phase to phase voltage could be 110V. \$\endgroup\$ – Reed Jan 3 '14 at 18:42
  • \$\begingroup\$ What is the reason for not wanting to use a transformer? \$\endgroup\$ – jippie Jan 3 '14 at 23:01
  • \$\begingroup\$ A 2:1 autotransformer is the usual way of deriving a 110 VAC supply from 230VAC. Why do you seek a transformerless solution? (Is this a practical problem, or a thought experiment?) \$\endgroup\$ – Li-aung Yip Jan 7 '14 at 7:18
  • \$\begingroup\$ A transformer is big and bulky. If it's possible to not use a transformer to do it it would be interesting. It's a thought experiment for now but if it's possible I would want to try it. \$\endgroup\$ – Reed Jan 8 '14 at 11:12
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Triac based light dimmers do this.

Varying the firing angle of the gate results in a reduced RMS output voltage. The output from this can be rectified and filtered however extreme caution should be exercised because the circuit has no galvanic isolation from the Neutral/Active lines and cannot be earth referenced if ELCB's are intalled.

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You don't say where you are. I'm not an electrician, but in the US, any one of the three phases will be 120 V to neutral, so the easiest way to get 120 will be to attach your outlet from one of the three phases to neutral. You don't need any electronics of any kind, but to be safe, you need to install everything per the electric code with circuit breakers and so-on. In the US, neutral wires are usually white. The three phases are red, black and blue (red and blue may be marked with tape). Ground wires are bare copper or green. Ground should not deliberately be used to carry current. It is for fault currents only.

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Have you checked all legs against neutral? Some 3 phase transformers tap so that two legs are 110v. http://en.wikipedia.org/wiki/High-leg_delta

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  • \$\begingroup\$ This doesn't answer the question, and should perhaps be a comment. \$\endgroup\$ – Anindo Ghosh Jan 3 '14 at 18:34

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