North American Network Operators Group
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Re: 220v/50hz power rig

  • From: Sean Donelan
  • Date: Thu Sep 06 13:52:54 2001 
On Thu, 06 September 2001, Alex Bligh wrote:
> a wide frequency tolerance. The only problem you may run into
> is that some boxes are too clever by half, and autosense input
> frequency to determine output frequency.

Actually, its not being clever, its being cheap.  If you use
the input frequency to drive the output frequency, you don't
need an extra crystal oscillator.  Its cheaper, and results
in fewer customer service calls about the clock running fast or
slow.  It also means, you can't just take a 50/Hz european UPS
and plug it into an US plug at 220vac, and expect to still get
50/Hz out of it.  When you plug it into the US grid, you'll get
60/Hz out.

I spent a day troubleshooting a problem, until someone explained
to me what was happening.  That's why I now use a bench power
supply, which explicitily generates the type of "international"
power I want, instead of using a Rube Goldburg setup.