Balancing of rotating masses • 1. Myfairtunes Patch 7.6. 8/25/2015 1 Hareesha N G, Dept of Aero Engg, DSCE, Blore • Unit 4: Balancing of Rotating Masses • Static and dynamic balancing • Balancing of single rotating mass by balancing masses in same plane and in different planes. • Balancing of several rotating masses by balancing masses in same plane and in different planes.

MECH2210 Experiment 2: Balancing of Rotating Masses 2 Theory Three masses m1, m2 and m3 are rotating in three planes at radii r1 to r3 at angles θ to a. Balancing of rotating masses. The balancing of rotating bodies is important to avoid vibration. In heavy industrial machines such as gas turbines and electric generators, vibration can cause catastrophic failure, as well as noise and discomfort. VTU EDUSAT PROGRAMME - 17 DYNAMICS OF MACHINES Subject Code -10 ME 54 BALANCING OF ROTATING MASSES INTRODUCTION: When man invented the wheel, he very quickly learnt.

8/25/2015 Hareesha N G, Dept of Aero Engg, DSCE, Blore 2 • What is Balancing? • Often an unbalance of forces is produced in rotary or reciprocating machinery due to the inertia forces associated with the moving masses. • Balancing is the process of designing or modifying machinery so that the unbalance is reduced to an acceptable level and if possible is eliminated entirely.

8/25/2015 Hareesha N G, Dept of Aero Engg, DSCE, Blore 3 • • A particle or mass moving in a circular path experiences a centripetal acceleration and a force is required to produce it. • An equal and opposite force acting radially outwards acts on the axis of rotation and is known as centrifugal force. • This is a disturbing force on the axis of rotation, the magnitude of which is constant but the direction changes with the rotation of the mass. • In a revolving rotor, the centrifugal force remains balanced as long as the centre of the mass of the rotor lies on the axis of the shaft. • When the centre of mass does not lie on the axis or there is an eccentricity, an unbalanced force is produced 8/25/2015 Hareesha N G, Dept of Aero Engg, DSCE, Blore 4 • Why Balancing is necessary? • The high speed of engines and other machines is a common phenomenon now-a-days.

• It is, therefore, very essential that all the rotating and reciprocating parts should be completely balanced as far as possible. Supcom Core Maximizer. • If these parts are not properly balanced, the dynamic forces are set up. Walking Life Torrent. • These forces not only increase the loads on bearings and stresses in the various members, but also produce unpleasant and even dangerous vibrations. 8/25/2015 Hareesha N G, Dept of Aero Engg, DSCE, Blore 5 • Balancing of Rotating Masses • Whenever a certain mass is attached to a rotating shaft, it exerts some centrifugal force, whose effect is to bend the shaft and to produce vibrations in it. • In order to prevent the effect of centrifugal force, another mass is attached to the opposite side of the shaft, at such a position so as to balance the effect of the centrifugal force of the first mass. • This is done in such a way that the centrifugal force of both the masses are made to be equal and opposite. • The process of providing the second mass in order to counteract the effect of the centrifugal force of the first mass, is called balancing of rotating masses.