Re: Why Buy a Converter?

On Wed, 2 Jul 2008 01:36:37 +0000 (UTC) Alan <nospam@xxxxxxxxxxxxxxxxx> wrote:
| In article <fv2fcv211fm@xxxxxxxxxxxxxxxxx> phil-news-nospam@xxxxxxxx writes:
|
|>There are a lot of things that could be better about the way electricity is
|>delivered to homes (maybe changing to DC is one of them).
|
| Unlikely. It is hard to get cheaper voltage conversion than a transformer.

If the load needs DC, the transformer is inadequate to the task.


|> But it is simply
|>not practical to make the change because so many things are not ready. One
|>such change I propose is increasing the voltage. It would be more efficient
|>in most circumstances. We know how to keep it safe, now. And for a great
|>many things, it's not hard to make them "240 ready".
|
| However, the losses are not huge, given that it only comes down from the
| pole to the house -- before that it is 12.5 or 15 KV.
|
| If you need 240 V, you have it in most houses. Call your electrician.

My point is the losses in the _wiring_ are less at 240V than at 120V. For
the wiring going into the home, which is sized for the expected total current,
there's no issue since half the 120V loads being in series with the other half
120V loads makes it effectively 240V. However, for individual branch circuits
using smaller (AWG #12 and #14) conductors, 240V would be less lossy than 120V
is.

I've examined a number of computer switching power supplies capable of being
run with either 120V or 240V. In no cases are any of them more efficient with
120V. While many have the same efficiency with either voltage, many others
are more efficient with 240V (according to the specifications listed on the
PSU or on the manufacturer web site).

WHy do many heavy commercial/industrial locations prefer running fluorescent
lighting on 277V instead of 120V?

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