Motor ME114 Fall 2007 Noe Garcia

The Problem Problem 19.169 A 400-kg motor supported by four springs, each of constant 150 kN/m, and a dashpot of constant c = 6500 N-s/m, is constrained to move vertically. Knowing that the unbalance of the rotor is equivalent to a 23-g mass located at a distance of 100 mm from the axis of rotation, determine for a speed of 800 rpm (a) the amplitude of the fluctuating force transmitted to the foundation, (b) the amplitude of the vertical motion of the motor.

Initial Creation Process * Inserting Correct UNITS

Continued Process Inserting Grid Lines

Continued Process Use the Polygon tab to create this figure Also use the anchor so the block will not fall due to gravity

Continued… Use the circle tabs and Square tab to finish drawing

Continued… Insert the springs with the specified spring constants. Also insert the damper

Continued……. * Insert a keyed slot joint so your motor can only move in the vertical direction

Continued……….. Now insert a 23g mass 100 mm from center radius of large circle as seen in picture. The large circle is the motor double click it to set up velocity and mass. You can do this to every object on your grid.

Continued…….. Now that the drawing is complete and all units correct, you can select the object you want measure (in this instance the spring) and click the Measure button on top. Now click the tab you want here I choose velocity of spring.

Simulation * When the Run Button was pressed the simulation started. * Press stop to stop simulation.

Simulation calc. and results Part a) I measured the amplitude Force (Fm) to be 5.89N

Simulation Calc. and Results Part b) Xm= 4.6*10^-5 m based on the simulation. The actual answer was Xm= 7.10 *10^-6 ****Im not sure what happened that the values were not close!

The End Credits http://www.mechanicalspring.com