Test with a multimeter on lowest ohm setting and you should get 4ohm plus resistance added by the meter itself (test this by connecting meter leads to each other and see what your base reading is). Also should read infinite when touched to any body ground through any ohm range on the meter. Sounds like your wires are not insulated from body good enough and you have a short to ground. I had a problem when rewiring mine and when assembling the alternator case I pinched my solder joints from the wires and was reading infinite all around... I had no connection after assembly, so no magnet, no electrical flow, and no blown fuse. Sounds like you have a short blowing the fuse.... I would guess reversing the connections would only yield the same result.
Best I can think of without more details, double check and mention anything else you may have touched, Would also suggest to test your voltage reg if the field coil failed at any point.
