So if you're Hunter ceiling fan starts making a grinding sound or if you smell smoke (plastic or otherwise), stop using the fan immediately and turn the circuit breaker off to the room that controls the fan.
I had this exact thing happen to my Hunter ceiling fan and ended up buying a new fan (thinking the old Hunter fan was going bad). However, after removing the fan and remote control receiver box, I noticed that the plastic smoke smell was coming from the receiver box connected to the ceiling fan. I took a look inside the receiver box, and sure enough a plastic transistor melted all over the circuit board, causing it to short out. I have a feeling my old fan still works fine, but I had already installed the new fan, so didn't get a chance to test it out. So long story short, if you have a remote control for your fan, check to see if the problem is actually coming from the remote receiver box (connected to the electric and fan), rather than the fan itself, as this seems to be a common problem with these Hunter remote receivers.
Keep in mind, the remote receiver box is typically located in the top portion of the fan, where the fan meets the ceiling / outlet box.