# When to Use More Than One Vibrator Motor?

Occasionally, two or more industrial vibrators maybe required if:

Either the diameter of a hopper or the longest side of a hopper exceeds 10 feet (3.05 m). When the amount of force needed to restore material flow exceeds the capacity of the preferred vibrator.

Example A:

If the force required is 5,000, force-pounds (22.24 kN), two vibrators, each with a minimum of 2,500 force-pounds ( 11.12 kN) rating may be used.

The following are a couple examples on how to select and size an vibration motor.

The following are a couple examples on how to select and size an industrial vibration motor.

Example B: Round Hopper

Diameter at Top – 8 ft (2.44 m), diameter at Discharge – 2 ft (.61 m), height of sloped portion of hopper – 5 ft (1.52 m), bulk material-granulated sugar – 45 lb per cubic foot.

Using the global calculator, we determine that there are 110 ft3 of volume in the sloped portion of the hopper, and that the bulk material weight is 4,948 pounds (2,244 kg).

Since granulated sugar weighs less than 9opounds per cubic foot and tends to flow freely, we will require only one pound of force per ten pounds of sugar (4,948 divided by 10 equals 495 pounds of force 2.20 kN.

Granulated sugar is a relatively “fine material”, so higher frequency vibration will be most effective.

The hopper dimensions are not excessive, so one vibrator will be sufficient.

Example C: Square Hopper

Dimension at Top – 8 ft x 16 ft (2.44 m x 4.88 m), dimension at discharge – 2 ftx 3 ft (.61 m x .91 m), height of sloped portion of hopper – 10 ft (3.05 m), bulk material gravel – 110 lb per cubic foot.

Using the Global Calculator, we determine that there are 539 ft3 of volume in the sloped portion of the hopper, and that the bulk material weight is 59,295 pounds (26,895 kg).

Since Gravel weighs more than 90 pounds per cubic foot but tends to flow freely, we will require only one pound of force per eight pounds of gravel (59,295 divided by 8 equals7, 412 pounds of force 33 kN.

Gravel is a relatively “coarse material”, so higher amplitude vibration will be most effective. The hopper dimensions are greater than the one vibrator capability, so more than one vibration motor will be required.