1. ENERGY AND VIBRATION Does vibration consume energy?

2. 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:

3. MIH-LO

4. VOLTAGE-LO

5. CURRENT-LO

6. 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:

7. MIH-HI

8. VOLTAGE-HI

9. CURRENT-HI

10. 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

11. 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.