This page is helpful for how they work. It even stated why they should not be used on appliances:
Why a GFCI should not be used with major appliances:
" A Ground Fault Circuit Interrupter is supposed to be a valuable safety device. Why not use them everywhere, even on large appliances with 3 wire plugs?
A properly grounded 3 prong outlet provides protection for both people and the appliance should a short circuit develop between a live wireand the cabinet.
Highly inductive loads like large motors or even fluorescent lamps or fixtures on the same circuit can cause nuisance tripping of GFCIs which needless to say is not desirable for something like a refrigerator."