In article , Michael A. Terrell wrote: : :Gunner Asch wrote: :> :> I live in a rural area west of Bakersfield..and I get 240-250 volts. One :> of my phase converters (on my Gorton Mastermill) really doesnt like it :> over about 242vts..and goes into alarm simply sitting there when the :> power is high. Many is the day in summer time that I couldnt use the :> mill until late at night when t he power drops below 242 volts. :> :> And Ive called PG&E..commonly known as Pacific Greed and Extortion...and :> complained..and I always get blown off because its "within 10% +/-" : : : Add a 'buck' transformer to lower it some. A high current 12 volt :transformer with its secondary connected in series, but out of phase :would give you about 238 volts when the line is 250 volts. of course, :the primary is connected to the AC line before the secondary. The :secondary of the transformer has to handle the full current of the load, :but some old battery charger transformers are big enough. Just make sure :to check the phasing before connecting the load.
The transformer will be happier if the primary sees the reduced voltage unless it has the extra iron needed to handle 250 volts without starting to get into the saturation region. In essence, you're making a voltage divider, but with transformer windings, not resistors.
| | | | | @ @ | | +-----+ +----------+ | +----| 12V |--+--| 240V |----+ +-----+ | +----------+ | | | | | | |
Mind the polarity dots. You're hooking this up in "boost" polarity, but then reversing the roles of input and output.