Problem? While outside, I noticed the air conditioner fan motor kept stopping and then starting again.?

It's working fine as far as keeping the house cool and is running steadily inside. But when I went outside near where the unit is located, I would hear it humming, then stopping, humming, then stopping, every couple of seconds over and over. The horizontal fan at the top would be spinning quickly, then the motor would sound like it clicked off and the fan would slow down. Then almost immediately the motor would sound like it clicked back on and the fan would speed up again. But inside the house everything sounds fine. I just never noticed this before and wondered if it's a sign of something that needs to be fixed. Thanks for any help!