1611. A Dynamic Balancing Primer

Paper

Abstract

Dynamic balancing is the process of physically adding, removing, or moving a portion of a rotating object’s mass to eliminate vibration during rotation. The term ‘dynamic’ is generally used to describe all spin balance efforts but actually applies to only one of four modes of rotational unbalance. Unnecessary vibration during rotation is a source of damage and energy loss. It produces increased maintenance requirements, decreased equipment life, greater inaccuracies where precision functioning is needed, increased weight due to higher fatigue loads, and additional acoustical pollution in an already noisy world. Reduction of unnecessary vibration will save money, time, natural resources, and health.
The information presented in this paper will contain the following:
– identification of each of the four modes of unbalance,
– common methods used to correct each mode of unbalance,
– details on constructing and using an elementary balancer from equipment normally found in an electronics lab and a relatively inexpensive transducer,
– and a computer program, written in BASIC, to aid use of the budget balancer.
Since this paper is written for the novice, balancing techniques will be limited to balancing at rotational speeds below excitation of natural bending modes. Balancing near or above natural bending modes requires equipment, techniques, time, and money outside the scope of the novice. Natural bending mode rates are often unknown when balance work is being performed and represent only a small percentage of the balancing spectrum. However, a discussion of the phenomenon observed when balancing speeds approach or pass natural bending modes is included. Thus, the reader may identify when a balancing effort is nearing such a region and take appropriate action.