Why natural frequency conveyors are not dangerous?

[Butters]

I've read that natural frequency conveyors are very efficient because the drive only compensates for the amplitude that's lost in the elastic supports. Could you please explain how is this different from working at resonant frequency which is so dangerous?

P.S. What kind of analysis should I use in my vibrating feeder design?

 

[Baluncore]

Could you please explain how is this different from working at resonant frequency which is so dangerous?

The natural frequency is the resonant frequency.
Operation at the resonant frequency may result in high amplitude oscillation. What will limit the amplitude ?