Stir Plate Wall Wart Rating

I finished a stir plate build, but am having a little trouble getting my head around the current rating needed of the wall wart. My fan is labeled 12VDC and .8A, and I am using a 9VDC 600ma wall wart, with a couple 3W resistors in place to get the speed I want. It's working fine, but now I'm starting to wonder, do I need a higher current rated wall wart? Or in the same way that the fan simply runs slower when I give it less than 12V, will it pull less current?

Based on the fan spec's, its internal resistance is 15ohms. Applying 9volts to 15ohms will draw .6amps (600millamps). Adding additional resistance in series with the fan will result in even less current draw. IMHO, you're good to go.

awesome, thanks. it didn't occur to me when I first wrote the post that I could also measure the current with a multimeter when it's running, and it was less than 200ma. Thanks!