Path: utzoo!utgpu!water!watmath!onfcanim!dave
From: dave@onfcanim.UUCP (Dave Martindale)
Newsgroups: sci.electronics
Subject: Re: Running 120V AC equipment off 240V AC.
Keywords: step-down transformer, resistive/inductive loads
Message-ID: <15566@onfcanim.UUCP>
Date: 4 Mar 88 04:56:31 GMT
References: <204@unh.UUCP> <1988Feb15.153838.5619@utzoo.uucp>
Reply-To: dave@onfcanim.UUCP (Dave Martindale)
Organization: National Film Board / Office national du film, Montreal
Lines: 19

>There is likely to be a little label on the back of your equipment giving
>things like voltage and power requirements.  If it says something like
>"47-63 Hz", as many of them do now, you're in the clear.  If it says
>"60 Hz", then you are gambling if you hook up to 50-Hz power:  it might
>work, it might overheat, it might fail completely.

And then there are the wonderful devices labelled "90-250 VAC 48-440 Hz".
For these, you just need the right power cord or adapter (such devices
usually have the "international" power input connector so the power cord
is changeable).

My Tektronix oscilloscope is like this - it accomplishes this by
full-wave rectifying the line voltage, then feeding the pulsating DC to
a switching regulator that provides 43 VDC out, which drives an inverter
that generates AC again at 20 KHz.  This is then fed to the main
power transformer, which produces both low and high voltages for
the instrument.

Thanks and a hat tip to manufacturers who do something like this.