[CAD_CAM_EDM_DRO] VFD single phase 5hp

Jon is correct (I think :-)



The reason that VFD's are not rated for single phase on larger motors is
that they are rarely used in this application. Depending on the
manufacturer's philosophy of design, some (TECO Westinghouse I think is one
outfit) can be run without de-rating, but most have to be de-rated by
50-100% for use on single phase. They are actually rated for watts per
phase, not HP during their design. In my experience, the manufacturers'
technical support departments are VERY helpful and will let you talk to an
application engineer before you buy, send operational/configuration manuals
etc. Do a bit of research and you may find that the only problem involved
is the number of bucks it will cost for a larger unit.



Hope this helps,

Jeff







Callcbm wrote:

>ANy body now were to get a vfd for a 5hp using single phase. I found one

for

>3hp single but not 5 hp single.
>willit hurt to use a 3hp on a 5 hp unit the lathe does and will not see
>using full power. Or would a Rotary converter be better.
>
>

If you don't run the motor at full power, or do that for more than a few
seconds at
a time, then you can run almost any VFD made after the 1980's on single
phase.
If you will be drawing rated power from the motor for extended periods
of time,
it is best to use a VFD with a higher power rating. So, you might use a
7.5 or even
10 Hp VFD with a 5 Hp motor. The only parts that know the difference
are the
rectifier and filter capacitors, and the larger VFD has a heavier-duty
set of these
components. I've been using a 1 Hp VFD from Magnetek on my 1 Hp Bridgeport
for 5 years now with no ill effects. I don't often draw full power from
the motor,
however, so I get away with it.

Jon



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