"Rick Cox" wrote in message
news
Frank,
Would the "Inrush" be listed in a typical Manual.
The VFD I have is a Toshiba model vfs7s 2007up. It was manufactured
in '97.
It is rated at 4.0 amps at 1.6kva 0.5-80hz.



The ability of this drive to run your fully loaded 1HP motor may
depend on the internal circuit design. A 220V, three-phase, 1HP motor
draws about 3.5 to 4 Amperes at full load. Although some drives have
rated short-time overload capability, the above rating doesn't allow
much headroom for overload. You didn't state the voltage rating of
the drive, but I'm guessing it has capability to 480V (or possibly
600V). That would make the 1.6kVA rating more plausible for its 4A
current rating. No matter what the kVA rating is - AMPS are AMPS, and
that will be the limitation for power output capability of the drive.

But, there's another issue here - using a VFD to convert single-phase
to three phase may also require some internal control circuit
modifications. Most three-phase VF drives still require three-phase
input to work properly AS DESIGNED. Since an AC drive uses an up
front rectifier section, it could be modified to use single-phase
input. But, the safe current load limit may be reduced, depending
upon the current rating of the rectifier power units (assuming you can
use a single input phase of the rectifier). Since the current rating
of your drive is already marginal for a 1HP, 220V motor at full load,
you might not get fully rated performance from your 1HP motor without
overloading the drive. (Discussion assumes the 'modification' is
already feasible - which may not be true.)

Most variable speed drives aren't typically used to convert
single-phase input to multi-phase output. Custom design may be
needed.

Just a few things to ponder,
John Sellers