It is possible to obtain two types of vibrations: ROTATIONAL: Using only one vibrator which generates a rotating centrifugal force around its own longitudinal axis transmitting it to the connected structure creating an elliptical movement (fig. 1). UNIDIRECTIONAL: Using two vibrators with equal features, rigidly fixed on the same plane and rotating in opposite direction. In this case the centrifugal forces created by the counterweights generate an unidirectional alternating vibration (fig. 2).

Revolution "n" (R.P.M.) and the working moment "M" (Kgmm) are the most important features of the vibrator. To select the revolution it is important to consider the type of the application an the type of the material. 3000 R.P.M. vibrators are chosen when a high frequency and low amplitude are required, generally used to avoid loose materials clogging in silos, hoppers, etc.

If the machine has to work in a continuos operating cycle or exceeding 2000 h/year it is advisable to operate vibrators at not more than 80% of their total centrifugal force. For all particular applications refer to our Technical Dept. VIBRATOR ADJUSTMENT There are two parameters available to modify the efficiency of a vibrating machine: Amplitude Revolution The amplitude can be altered by adjusting the weights only after having stopped the motor. Revolution can be regulated by inserting a frequency changer (inverter). The regulations can then be made when the motor is running, directly by means of the inverter or by a remote control. It is also possible to limit the oscillations which occur when the motor is switched off by using the braking characteristics of the inverter. For the selection and the setting of the inverter it is necessary to consider: 1. All vibrators installed on the same machine must start together and be fed by the same inverter. 2. It is important not to exceed the nominal speed of the vibrator, and to avoid resonance problems, not to operate with less than 50% of this speed. 3. To assure good starting of the motor, we advise to utilize a converter with a normal capacity, which is 2-3 times as much as the total capacity of all vibrators installed on the structure.