Shelley was a key member of a close circle of visionary poets and writers that included Lord Byron; Leigh Hunt; Thomas Love Peacock; and his own second wife, Mary Shelley, the author of Frankenstein.
If the 900 watts means the input power, then 1000 w inverter would be ok. If the microwave produces 900 w of cooking power, you will need a bit more, maybe 1200-1400 w if you don't know what the input power rating of the microwave is.
Full Answer. Over-the-range microwave oven designs are often wider than typical countertop microwave models, which are typically anywhere from 18 to 24 inches wide. Wattages for over-the-range microwaves are similar to countertop models, ranging from 600 to 1200 watts.