buzzing

by sharon
(green bay, wi, usa)

My central A/C unit attempts to turn on, makes a buzzing sound for 1-2 sec. then clicks off. It seems as if there is a sensor telling it to 'time out'.

The fan blade will move just a cm. or so. The power works fine. Could the problem be something simple like too much dirt, debris around the base of the unit, coils?