🚀 go-pugleaf

My brother received a "PowerStat" 12VDC - > 117VAC inverter over the holidays.
It has been a real disappointment. The ad claimed it was good for 140W normal
and 200W peak power. It barely manages 100W into a resistive load (lamp), and
it simply cannot drive even the smallest drill (its intended use). My EE degree
and scope can't help (I live half a continent away) hence this net posting.

To anyone with experience or familiarity with this/such beasts:

  (1) How can he test it a/o improve its output?
  (2) How can he better cope with power factor/inductive loads?

It strikes me that a series cap would be prohibitively large. Or maybe the
"modified sinewave" harmonic content is hell on a motor. Or perhaps I can send
him a matched pair of industrial strength VFETS (??). A circuit diagram would
help, or at least confirm/deny my suspicions that "100VA max, non-reactive
loads only" is about all one can expect. E-mail most welcome. Many thanks.

   /Alan Paeth VE3AWP
   Computer Graphics Laboratory, University of Waterloo