[X4U] world adapter kit

[Doug McNutt]

At 16:27 -0500 5/13/08, Ed Gould wrote:
>You (and others might be correct) [with regart to frwequency conversion]. I was going on information from 40  years ago. Items back then might not have been converted easily (60  to 50) cycles. I remember rather large copper colored boxes (16" by  8" by 6" or larger) boxes that heated up excessively for use with  appliances brought over from the US to Germany. Maybe computer makers  have figured out the technical issues to make the boxes obsolete by now.

For at least a decade electronic equipment has started off with a power supply that first rectifies whatever power is offered. The rectified voltage, now DC at about 360 volts, is fed to an oscillator that runs at a few hundred kilohertz to drive a small transformer that  has secondary windings appropriate for the downstream voltages. High frequency translates to smaller and lighter transformers.

Those power supplies will operate fine with 360 volts DC input and I have seen them running with 100 volt 400 Hz power. There are companies now producing them for 12 and 24 volt DC input. (I'm seriously considering using one with an automotive battery and a solar collector.)

The problems of old were with vacuum tube radios that used plain old iron core transformers to generate a few hundred volts DC. Those heavy beasts could suffer from magnetic saturation of their iron cores at lower than design frequency. That translates to heat and melting of the tar that holds the windings in place.

At one time the fans in electronics were run directly from the power line and they could get confused with different voltages or frequency. Fans these days all operate on 5 or 12 volts DC the same as used for disk drives.

It is now possible to specify 90 to 160 volts AC as an input range without any modifications. Some older electronics might have a switch at the plug for selecting two ranges. Those change between bridge rectifiers for 220 volts or so and a voltage doubler for 110 volts range. Just set them correctly.

European countries have rules to prevent harmonic currents in the power lines caused by those input rectifiers which tend to draw current only at the positive and negative peaks of the power lines. Harmonic attenuator modules are somewhat sensitive to frequency but they all will handle both 50 and 60 Hz. They might have a problem with the 25 Hz stuff that can still be found at Niagra Falls.

<ftp://ftp.macnauchtan.com/Theory/Current.pdf>  259 kB
<ftp://ftp.macnauchtan.com/Theory/Harmony_101.pdf>  194 kB

are a couple of technical papers I once wrote about it.

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