Guide on Purchasing a Dynamic Balancer

The dynamic balancer is a single-purpose apparatus for measuring the amount of unbalance and its phase for various rotary parts (rotors) used in machinery. By making calibrations to the amount of unbalance of a rotor based on the measurement result achieved by a dynamic balancer, the vibration generated by the rotor or caused to the bearings when it rotates will be reduced to the permissible range. This helps to reach the goal of reducing the vibration of a product, improving its performance and enhancing its product quality.

I. Classification of dynamic balancers:
     Basically, dynamic balancers can be divided based on either the measurement principle or the scope of application:
     1. So long as the measurement principle is concerned, there are two big categories, hard support dynamic balancers and soft support dynamic balancers.
       (1) A hard support dynamic balancer possesses such merits as a balanced rotation speed lower than the natural frequency of the supporting system for the rotor, the ability to conduct dynamic balance calibrations even at low rotation speed, ease of operation, and excellent safety.
       (2) A soft support dynamic balancer has such merits as a balanced rotation speed higher than the natural frequency of the supporting system for the rotor, strong resistance against vibration signals from the outside, a high measurement accuracy, and excellent suitability for mass production.

     2. In light of the scope of application, dynamic balancers can be divided into two big categories, horizontal and vertical dynamic balancers and general-purpose and single-purpose dynamic balancers.
       (1) Horizontal and vertical dynamic balancers
     A horizontal dynamic balancer refers to any dynamic balancer in which the axis of rotation of the rotor to be balanced is horizontal. Normally, horizontal dynamic balancers are fit to test rotors that come equipped with a rotating shaft or that can be equipped with a rotor easily, including motor rotors, wind wheels, fan blades, rollers, rubber rollers, shafts, printing machinery, etc. Products like the CYYQ and CYYW machines manufactured by our factory belong to the horizontal dynamic balancer category.
     A vertical dynamic balancer refers to any dynamic balancer in which the axis of rotation of the rotor to be balanced is vertical. Normally, vertical dynamic balancers are fit to test disc-shaped rotary parts that do not come equipped with a rotating shaft, including fan blades, impellers of water pumps, wind wheels of suction fans, flywheels, grinding wheels, saw blades, chucks, brakes, etc. Products like the CYLD machine manufactured by our factory belong to the vertical dynamic balancer category.
       (2) General-purpose and single-purpose dynamic balancers
     A general-purpose dynamic balancer is a balancer that can be used to balance many types of rotors within its specified ranges of rotor weight and rotation speed. Products like the CYYQ and CYYW machines manufactured by our factory belong to the general-purpose dynamic balancer category.
     A single-purpose dynamic balancer is a balancer that is designed for a specific type of rotors. Products like the CRYD-100 and CYYQ-T16 machines are single-purpose dynamic balancers specially designed for testing automotive drive shafts and wind wheels of air conditioners.

II. Brief introduction to the naming principle of dynamic balancers
     Normally, the model number of a dynamic balancer consists of two parts, the alphabetic part and the numerical part. The alphabetic part represents the structural characteristics of the dynamic balancer while the numerical part expresses the characteristic parameters of the dynamic balancer (generally referring to the maximum mass of the rotor). The model number is represented in the following manner:
For example, CYYQ-160

C —— 1. Indicates the mode adopted for displaying the test result (displayed by means of a computer)
Y ———— 2. Indicates the mode adopted for testing the vibration (hard support)
Y —————— 3. Indicates the type of machine (general-purpose horizontal)
Q ———————— 4. Indicates the mode in which the rotor is driven (circular belt drive)
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160 —————————— 5. Indicates the maximum mass of the rotor (160kg)

     A description of the alphabetic characters normally used in the model numbers of dynamic balancers is as follows:

III. Relevant information on how to select a dynamic balancer
     As rotary machines are becoming more and more diversified, so are the requirements in such aspects as vibration, noise, service life, etc. An appropriate dynamic balancer must be selected for a certain type of rotary parts based on the characteristics of the specific type and once a measurement is made, a calibration must also be given to the amounts of unbalance measured accordingly.

    1. General principle used in model selection
       Step 1: Select an appropriate type of dynamic balancer, a horizontal or vertical dynamic balancer, by taking into consideration the characteristics of the shape of the rotary part and by making reference to the previous sections explaining the purposes of various types of dynamic balancers. Of course, if there are any special needs available, a dynamic balancer can still be designed and manufactured according to the customer concerned.
       Step 2: Select a model with the appropriate size based on the characteristic parameters of the rotary part, including outside diameter, length, weight, etc. (the size, represented by the numerical part of the model number, may be 5, 16, 50, 160 or some other number). The size expressed as a number indicates the permissible maximum mass of the rotary part. Normally, a rotary part to be tested shall be one third or two thirds of the permissible maximum mass specified for the dynamic balancer. Although a rotary part with a mass without this range can be tested on the dynamic balance, the desired accuracy may not be obtained.
       Step 3: If an appropriate dynamic balancer can not be selected with all the methods mentioned above, you can contact our sales engineers by telephone, fax or e-mail. So long as you provide them with the data required for conducting dynamic balance measurements, we will be able to provide satisfactory technical consultation services, thereby letting you purchase an appropriate dynamic balancer.

     2. Explanation of terminology
       (1) Minimum attainable residual degree of unbalance
       It refers to the minimum degree of unbalance that can be reached for the rotary part by using the dynamic balancer. It serves as the index for measuring the maximum balancing capacity of a dynamic balancer, usually expressed in g.mm/kg.
       (2) Rate of unbalance reduction
       It refers to the ratio of the amount of unbalance reduced after one calibration by the dynamic balancer to the original amount of unbalance. It serves as the index for measuring the efficiency in balancing, usually expressed as a percentage.

       Finally, we wish you to purchase the most satisfactory dynamic balancer that can help you improve your products’ quality, thereby bringing you a huge fortune!