Dynamic balancing
Damaged rotor blades can cause imbalance. When this imbalance exceeds the permissible tolerance, vibrations and produced which wear the bearings and in the long-term cause major damage to the entire turbocharger. Extensive repairs and downtime are then unavoidable.
Before a rotor can be balanced, it is first necessary to check that the runout of the shaft and the deflection of the compressor wheels are still within the permitted tolerances. If these measurements are satisfactory or after remedial work, the rotor is examined for imbalance on a microprocessor controlled test bench, according to the ISO 1940 standards.
The complete rotor is placed on the balancingmachine and the partition wall is independently supported. Even though unbalance may not have been evident before overhaul and calibration, it is possible that it could be introduced during dismantling and repair procedures and it is therefore paramount that dynamic balancing is carried out before the rotor is returned to service.
If the unbalance is found to exceed the makers limit, it is corrected by grinding down the appropriate correction planes on the rotor. Accurate balancing is of the utmost importance and not a single rotor leaves the PJ Diesel workshop without having been tested and, if necessary, corrected.
