On Mon, Jul 6, 2009 at 11:09 AM, Mark
Scoville<mscoville@unicontrolinc.com> wrote:
> Hi Piclisters,
>
> I have a project at work that I need to test while powered from 120Vac 50Hz.
> All I have available in the USA (Cleveland, Ohio) is 60Hz. Does anyone have
> any clever and inexpensive ideas for how to generate 120Vac 50Hz? I need
> about 4 amps to do my testing.
>
> So far my thought is to buy a "Modified Sine" inverter ($100) that runs off
> 12Vdc and produces 220Vac at 50Hz. Then I could step down the 220Vac using a
> transformer (which we already have). It's not very elegant, and not ideal,
> but this is only needed for a few days of testing and then will probably sit
> on a shelf for 20 years getting dusty.
>
> Anybody have any other ideas besides a really long extension cord to a
> country that uses 50Hz.
>
> -- Mark
>
>
>

Link two AC induction motors by a set of pullys and a V belt. The
frequency (also voltage) should be somewhat lower than 60Hz due to
slip. You will have to momentarily flash the field to start the
magnetic field on the generating side. If you had a DC series motor
(or ACIM + VFD) you could spin it at a variable speed to ensure that
it stayed at the frequency you desire.

I expect that the voltage will be lower than you would want to deal
with in this case. I just thought I'd throw out a cheap option if you
have the parts.

--
Martin K.
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