The present invention describes a system for taking the necessary energy for operating the electronic circuit for monitoring a bearing (A) directly from the rotation movement, namely from the kinetic energy of the bearing i.e by energy harvesting or scavenging. All information read on board the bearing (A) by the sensors (4a, 4b) are sent through radio with a wireless communication system to an external data collecting and processing unit (6), that is able to evaluate and communicate the status of the bearing (A) being analyzed. The preferred system embodiment provides that the generator (1) bases its operation on the gyroscope (or Coriolis force) effect a circuit (7) for accumulating the necessary energy for turning the system on.