On multi-speed motors, what specifically are the green, red, black, blue, and purple wires for?

Answer 1

DC-AC what ? There is usually a motor tag with a diagram. Maybe its on the inside termination cover.

Answer 2

Please note, not all manufactures follow a standard color code.
Red is leg one, power in (but it could be black), black or white could be Leg 2, power out (return power). Green could be the ground wire (or it could be brown). Blue could be low speed, purple high speed. I worked on different and blower motors, nothing seems standard, I don't mean to confuse you but give you a guideline. I guess you don't have a wiring diagram, if not you could use a voltmeter to check each wire.