[Boatanchors] 3-phase for BA transmitters?

[David Ross]

Nick & the gang -

   Most of the VFDs that you will find require three-phase input power.

   A couple of the smaller Motortronics VFDs will run on vanilla 220 
though, I have one here.  It is rated at something like 2500 VA and that 
is with single-phase 220V input and three-phase output.

   I have used it to run 400~ radios.  It has some nice features, like a 
variable-speed ramp-up so that it doesn't go from 0V to 120V instantly.

   The one thing that totally kills it's usefulness to me is that the 
VFD make a huge amount of electrical noise.  Might be OK if you are 
going to run a transmitter with it, but the noise will wipe out any 
nearby receiver.

73, good luck
Dave Ross    N7EPI



On 11/18/2012 1:35 PM, Nick England wrote:
> Has anyone actually tried a Variable Frequency Drive as a way of
> obtaining 3-phase for vintage high power transmitters?
> VFD's are solid state devices that are normally used as motor
> controllers, and they are available as 220v 1-phase to 3-phase
> converters.
> BUT (big BUT) all the ones I have seen say DO NOT switch the load
> (which is exactly what you need to do in a transmitter).
> I'm also wary about xfmr heating from harmonics from these switching gadgets.
>
> Any direct experience with transmitter applications - or a pointer to
> some gadget I've missed that woud be happy in the application - is
> greatly appreciated.
>
> So far the only solution I have seen is a rotary converter
> (motor-generator) for 1-phase to 3-phase conversion.
> cheers,
> Nick K4NYW
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