One of the oldest methods of balancing is shop balancing, and many balancing machines have been developed for this purpose over the years. These balancing machines have various classifications, but the most common categorization divides them into two types:

1. Hard Bearing Balancing Machine

2. Soft Bearing Balancing Machine

The shop balancing services provided by Tavater Sepahan Engineering Company include a soft bearing balancing machine with no length or radius limitations, capable of handling loads up to 1.5 meters.

Hard Bearing Balancing Machine

Balancing machines are usually of the hard bearing type. These machines are widely used, and most balancing workshops utilize this kind of machine because there is no need to use a test mass for each rotor. Once the balancing machine is calibrated, it can be used for all defined rotors within the machine’s capacity range. For this reason, deviations from calibration may occur with these machines, necessitating periodic calibration inspections.

The sensors in these devices are generally of the electromagnetic type with very high sensitivity, capable of accurately measuring the rate of change of the base’s vibrational distortion. The drive system typically transmits power through a drive shaft from a gearbox that allows for the selection of different speed ratios. The chassis supporting the bearings should be installed on a specific foundation.

Soft Bearing Balancing Machine

The bearing system of this type of balancing machine has very little stiffness in a specific direction (usually horizontal), unlike the hard bearing type, and shows minimal resistance to unbalance forces. Therefore, unbalance in the rotor can be easily identified at low speeds. However, a challenge with this system is that the rotor’s mass and its transverse rotational inertia affect the movement response, necessitating recalibration of the balancing machine for each rotor. This calibration is performed by applying a test mass, which means that depending on the number of balancing plates, more setups and consequently more balancing time are required.

On the other hand, this type of balancing machine can efficiently balance heavy rotors at low speeds, requiring less power consumption. The bases of these machines do not need special foundations and can be easily installed on any workshop surface, which usually eliminates length restrictions for this type of balancing machine. The drive system of these machines typically uses a belt drive, as low torque is generally required for rotor rotation. Another point to note is that since the balancing machine is calibrated for each rotor, it helps prevent calibration errors that may occur with the hard bearing type.