[Milsurplus] VFD for 3 ph 115vac at 400 cycles

[Robert P. Meadows]

Folks, keep searching for solid state 115v 400cps, or as I did, a rather
large MG Set that makes enough 115v3ph400cps to run about four 618T/628T.

R

 

From: milsurplus-bounces at mailman.qth.net
<milsurplus-bounces at mailman.qth.net> On Behalf Of John P. Caldwell
Sent: Tuesday, February 12, 2019 6:17 PM
To: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] VFD for 3 ph 115vac at 400 cycles

 

Don't get ahead of yourselves here, I don't think this is going to work as
you'd like.  3 phase VFD's are intended for motor speed control and as Nick
observed, don't deal with load changes instantaneously.  For example, in the
scenario where you try using one to supply power to a 618T-2 aircraft
transceiver, the transformers in the radios power supply will go into
saturation when the output frequency of the VFD sags due to load peaks.
Even for a millisecond, if the frequency drops, the power supply will shut
down.  It might be possible to use a large motor to act in a stabilizing
role to buffer the VFD's load and stabilize the frequency, but I can't say
for sure.   Then there's the square wave output issue to deal with as well,
VFD's don't make clean waveforms.  Expect lots of line noise as Peter
pointed out.

 

John

WD8INC

 

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