When I had the Taurus fan on my Mustang, I had no problems powering it with the stock 60 or 75 amp alternator (I forgot which one it was). I didn't have alot of accessories drawing power from the alternator, but the heavier duty alt on the Explorer should do fine with the extra draw along with all it's accessories.
Mine was set up with a relay for the low speed and a non-adjustable thermostat in the fins of the radiator and it worked fine. The high speed was connected to a relay and to a switch in the car, but I never had to use it. The car never overheated or blew the fuse or the relays either. I can't remember what size fuse I used for the relays though. I wouldn't hesitate to use a Taurus fan again. In fact it'll be going on my Explorer soon...er...eventually.
I only swapped it out for the Black Magic 185 because I liked how much nicer the 185 looked. I'm not entirely confident with it yet though. It's a single speed and runs a little hotter (don't know the exact numbers, just higher on the unmarked temp gauge) than with the Taurus on its low speed setting. I can't be sure its the fan's fault though since I also changed and upgraded my entire combo...block, heads, cam, water pump, radiator, 3G alternator, computer tune, and a few other things, so I'll have to swap the Taurus fan back in for awhile to test it sometime.