The oldest balancing methods are workshop balancing services, and so far many balancing machines have been developed for this purpose. These balance machines have various categories, but in the most general category, they are divided into the following two categories:

Hard Bearing Balancing Machine
Soft Bearing Balancing Machine

Workshop balance services of Tavator Sepahan Engineering Company has a balance machine of the type of suspended bearing without limitation of length and radius of 1.5 meters.

Hard Bearing Balancing Machine

Balancing machine is usually of fixed bearing type. This type of balance machine is widely used and most balance workshops use this type of balance machine because there is no need to use a test mass for each rotor. Once the balance machine is calibrated, then it can be used for all defined rotors within the capacity range of the machine. For this reason, an out-of-calibration error occurs in these types of machines, and they require periodic calibration inspections. The sensors of this type of device are generally of the electromagnetic type with very high sensitivity, which can measure the speed of the vibration deformation of the base with high accuracy, and its driver is usually in the form of power transmission by the gearbox from a gear box with the possibility of choosing the ratio of different revolutions. The bearing support chassis must be installed on a special foundation.

Soft Bearing Balancing Machine

The bearing system of this type of balance machine, unlike the fixed bearing type, has very little hardness in a certain direction (usually horizontal) and shows the least resistance against the imbalance force. Hence, rotor imbalance can be easily detected at low speeds. But the problem is that the mass of the rotor and its transverse rotational inertia are effective in the motion response, and therefore the balance machine must be calibrated for each rotor. This calibration is performed by applying a test mass and therefore requires more setups depending on the number of balance plates and therefore more balance time.
On the other hand, this balancing machine can be used to balance heavy rotors at low speed and requires less power consumption.
The bases of this type of machine do not need a special foundation and it can be easily installed at any level of the workshop. Therefore, there is usually no length limit in this type of balance machine. The drive of these types of machines is generally of the belt type because a low torque is usually needed for the rotation of the rotor. Another point is that because the balance machine is calibrated for each rotor, calibration errors that may occur in the fixed bearing type are avoided.