Unbalance is often defined as, simply, the unequal distribution of weight about a rotor’s centerline. The ISO defines it as a condition that exists in a rotor when the vibratory force or motion is imparted to its bearings because of centrifugal forces. Correction of this unequal distribution of weight about a rotor is called balancing.
Dynamic unbalance is the most common type, and the result of static and coupled unbalance. The principal mass axis is displaced and not parallel to the shaft centre line.
In-situ Balancing is done by a Specialist Engineer following ISO standards 1940-1
− Single plane Balancing
− Two plane Balancing
− High Speed/Turbomachinery Balancing (Flexible Rotor Balancing)
Balancing is the process of adding (or removing) mass on a rotor to shift a central principal inertia axis to coincide with the geometric axis of rotation.
Balancing is done by drilling, welding, sticking with adhesive, milling, grinding or attaching screws. Unbalance is the most common malfunction of rotating machines. Reasons for unbalance could be many, like; manufacturing irregularities produced by poor original balancing, machining errors, cumulative assembly tolerances, distortions due to heat treatment, flaws or inclusions in castings, and material non-homogeneity. Irregularities occurring during operation include uneven wearing and erosion, the unsymmetrical buildup of deposits, missing or loose rotor parts, and load-related and thermal distortion of the rotor.
Our specialists follow the below procedure:
− Confirm unbalance by differentiating with equipment problems using phase and spectrum analysis
− Check locations to add/weld weight. Arrange different types of weights
− Check the blade condition. Count the number of blades, check access to the machine
− Check startup and stop conditions and understand the difficulty and delays
− Setup the latest technology balancing portable instrument with laser phase reference probe
− Carry out the trial run and put trial weight and from the result do the trim till the client desired levels of balancing on pure unbalance are achieved
− Use the polar plots and vector methods of calculation simultaneously along with the instrument calculation to confirm the correction procedure with a minimal run