The Dynamics of Rotary Vibrators
Unlike linear vibrators, rotary vibrators generate vibratory force through the rotation of an eccentric weight. Similar to how a household washing machine vibrates when its load is off-center, these rotary vibrators are adept at moving fine, dry materials. 
They can be powered pneumatically, hydraulically, or electrically, with the choice often dictated by the available energy source at the installation point.
In rotary pneumatic vibrators, a stream of air propels a mass in a circular path to create vibration; in rotary hydraulic vibrators, hydraulic fluid achieves the same effect. Meanwhile, in rotary electric vibrators, eccentric weights are typically affixed to an electric motor rotor or shaft.
Rotary vibrators are manufactured in various sizes and capacities to suit specific applications. Many rotary electric vibrators offer adjustability by modifying the overlap of the eccentric weights, thus varying the unbalance to achieve the desired vibratory force.
Vibration can stress metal structures, necessitating reinforcement at the application points. Like linear vibrators, rotary variants are usually mounted on a plate or channel to distribute vibratory energy and device weight over a larger area.
For chutes or hoppers, rotary vibrators are sized based on a 1:10 ratio of output force to the mass of material inside. Finer materials typically require higher frequencies to induce flow.
Typically, on a chute, a rotary vibrator is installed in the lower one-fourth to one-third of the structure. If a second vibrator is needed, it should be mounted 180 degrees opposite the first, halfway up the structure.
Rotary vibrators can be operated manually or automatically, allowing for use only when necessary. Once installed, tuning involves adjusting the force and/or speed to optimize performance for each specific application.