Unbalanced rotor is one of the main reasons of vibration in rotating machinery. In order to achieve the minimum amplitude of vibration, the amount of unbalance weight should approaches to the minimum. Balancing is one of those activities which has to be done on the rotor or any other rotary parts before the assembly of machinery. In the other word, unequal weight in different positions of rotor causes a turning force during rotation of the rotor, which has a direct relation with rotating speed and the distance between weight and gravity center of the rotor. The produced force by extra weight on the rotor is known as unbalance force. This unbalance force can cause vibration in rotating equipment. In fact, balancing approaches the resultant forces to minimum during the rotation. Therefore by balancing, it’s feasible to achieve the minimum vibration caused by unbalance mass. Rotating machinery need to be balanced before and after installation. Before the assembly of equipment, balancing is one of those activities which has to be done on the rotor. In some critical equipment, even after the installation of machinery, the balancing of the rotor has to be checked and re-balancing scheduled if needed. Some reasons of unbalancing are wear or erosion of impeller, sediment on impeller, rotor partial crack and … The unbalance forces on the installed rotating equipment are detected by CM experts using vibration instruments. For balancing, the rotor could be sent to the workshop or balanced in the field sometimes. Regarding the importance of balancing, the repeatability in some equipment and consequently the effect on reduction of vibration amplitude, field balancing is done by the experts of BASAMAD company. Also a training course titled “balancing of rotating equipment” is planned in this company. Course outline is accessible in the download section of our website.