This is the overtemp/current protector (think of it as a self resetting circut breaker) on the side of the compressor opening and closing as the compressor tries to start (which for some reason it's not) if the unit hasn't run in a while it may be a little stuck, or it could have a bad start winding or it's locked up. you could try a 3 in 1 starter unit on it (if were just low on freon it would start OK then it would turn on/off as the compressor over-heated) so if the 3 in 1 doesn't do the trick it's gonna be rebuild time
'> has this machine ever ran? hope this helps!