Drive Systems

There are four broad categories of drive systems for vibrating equipment. These include:

Direct Drive

Direct drive vibrating feeder.
Direct drive vibrating feeder.

Direct drive describes vibrating equipment that is excited directly through the use of rotating out of balance weights.

Motors that drive the weights can be either integral to the motor in lighter duty applications or external as in the case of large mining screens.

These are the simplest types of vibrating screens and vibrating feeders available. Hence the most popular.

Pros Cons
  • Rugged drive system.
  • Simple to run and maintain.
  • Will not over stroke when overloaded.
  • Small feed rate control.
  • Stroke will not adjust to a variance in loading.
  • Limited scope for upgrade if throughput is increased.
  • High dynamic forces passed to sub structure.
  • Violent start / stops.

Twin Mass

Twin mass drive vibrating feeder.
Twin mass drive vibrating feeder.

Twin mass drive systems are tuned to operate at just below the natural frequency of spring systems to convey vibrating forces to material.

Excitation is provided by standard out of balance motors.

These systems are more complex but energy efficient which results the ability to make much larger equipment using standard parts.

Pros Cons
  • Allows cost effective construction of equipment longer than 6m and heavier than 5000kg.
  • Up to 30% more energy efficient.
  • Large feed rate control.
  • Adjustable to varying material loads.
  • High strokes to assist with difficult material.
  • ‘Pulsing’ can be achieved to clear screens.
  • If a single motor fails the equipment may still operate.
  • Some scope for upgrade with electronic frequency adjustments.
  • Can self destruct if material is sticky.
  • Generally more expensive to build.
  • More components involved in drive system.

Natural Frequency

Similar to Twin Mass drive systems, Natural Frequency machines use resonance but operate much closer to it.

A crank arm is used which will control each vibration cycle reliably. As a result, constant feed rates can be expected from this equipment.

Machines up to 20m in length can be built with this system.

Pros Cons
  • Energy efficient.
  • Simple and reliable.
  • High hygiene designs can be manufactured easily.
  • Long equipment can be made.
  • Lighter duty applications only.
  • Little adjust ability.
  • Cannot take head loads.

Electromagnetic

Vibrating feeder with electromagnetic drive system.
Vibrating feeder with electromagnetic drive system.

Electromagnetic vibrating machinery uses a high frequency coil to provide the vibration.

Used in lighter weight applications and can provide a high degree of fine feed rate control.

They operate at low strokes and very high rpm. Therefore, they are used in lighter weight applications and can provide a high degree of fine feed rate control.

Pros Cons
  • Energy efficient.
  • Simple and reliable.
  • Hygiene designs can be manufactured easily.
  • Low stroke is gentle on fragile material.
  • High feed rate control. Great for dosing applications.
  • Require a reliable power supply.
  • Only allows the manufacture of short units.
  • Low stroke can be too gently for some applications.