ENERGY AND VIBRATION

Does vibration consume energy?

General conditions:

• Motor GE, 1/3 hp, single-phase, 3450 rpm, 115 Volts bolted to the working table of a drill press.

• In order to increase the resolution the voltage was decreased to about 40 Volts.

• No attempt was made to balance the motor, but initially the vibration was reasonably low.

• The unbalance was created by adding weight (23 grams) to the pulley on diameter 1.5”.

• Following are data from the initial run:

MIH-LO

VOLTAGE-LO

CURRENT-LO

COMMENTS:• The overall vibration in horizontal direction was about 0.085 in/sec

mainly due to 1x.

• The vertical vibration was similar.

• Note the speed of 3553 rpm.

• The voltage is almost pure sine-wave (very low distortion – see the spectrum).

• The current is distorted more. But this distortion is nothing out of ordinary.

• The watts calculated from voltage and current: 47.38 W.

• Weight of 23 grams was added to the pulley at 1.5” radius.

• Every effort was made to keep the voltage constant

• Following slides are from the high vibration run:

MIH-HI

VOLTAGE-HI

CURRENT-HI

COMMENTS:

• The overall vibration increased to 1.5 in/sec (similarly in vertical direction.

• Note the speed of 3539 rpm.

• No change in voltage, the current increased from 1.66 Amp to 1.94 Amps.

• The calculated watts: 61.95 W

CONCLUSIONS:

• The increased vibration caused drop in speed from 3553 RPM to 3539 RPM.

• The required watts have increased from 47.38 W to 61.95 W.