[GreenKeys] Need motor for 50Hz supply (or DC)

[John Spigel]

Malcolm,
Doug Jones has it correct on the cost. You can run one or two Model 15s 
off one 500W pure sine wave inverter with a 12v deep cycle battery for 
several hours. I've done this when in the field away from the mains. You 
can add a small charger for longer runs or beefier 12v supply without 
the battery. So should be no problem for a 28.

Just make sure you get a 60Hz unit if ordering from your side of the 
globe. Some ads won't tell you. I paid about $65 US.
They do make static converters 220V 50Hz to 120V 60Hz. But they are 
pricey.

The motor may run a bit hotter at 50Hz than 60. If it still has a label. 
and it says 60 it may run fine at 50. It may also say 50/60.  The torque 
is less at the lower frequency and the iron loss and current go up. That 
is why VFDs must lower voltage with frequency. If needed running it at a 
little bit lower voltage with series resistor may help keep it cooler.

If you can determine exact gear catalog part numbers, Mr. RTTY or 
another greenkeyer may be able to come up with them.

What baud was your 28 originally?
I have a few test files available at 5bits.net and can easily make up a 
few for the baud you would like to try.

Doug also mention gen sets. You could run a gas generator at 60Hz 
instead of 50. Just a governor adjustment. I think you would rather 
listen to the TTY unit than the  generator But, then there's also the 
inverter generators that are very quiet.

73, John W1AN





On 03-Sep-26 22:11, Jones, Douglas W via GreenKeys wrote:
> I'm surprised nobody has mentioned motor-generator sets in this thread.  That's odd, because MG sets were used all over the place in RTTY work back in the vacuum-tube era to get plate voltage from automotive sources.  As a kid, I had a WWII surplus MG set that I used to play with.
> 
> For the case in point, a motor rated to run on Ausralian line current driving a generator designed to produce US line current would solve the problem.
> 
> A cheaper solution would be to get an inverter designed to produce 120V 60 Hz from, say, 12V, and then power this with a 12V supply derived from the local 50Hz mains.  Far simpler than a VFD, and inverters with enough power to run a TTY are pretty common.  Just make sure it's one that advertises "true sinusoidal output", because cheap inverters that output a square wave are lousy for running induction motors.
> 
>             Doug Jones
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