The apt Group offers a Field Balancing service for rotating machinery. The benefit of field balancing over shop balancing is explained.
It is common to remove a rotor from a machine and send it to a shop for balancing on a test-stand. In some cases this may be the only practical means of balancing; in other cases a shop balance may not be possible. Occasionally, a rotor which has been shop-balanced will yield poor (or even worse than-original) balance-vibration results when re-installed and operated. This does not necessarily mean that the rotor was incorrectly balanced in the shop - it may result from differences between test-stand conditions and operating conditions.
A shop test-stand will have different bearings, bearing spans, structural response, stiffness, mechanical impedance, etc. - the test-stand cannot duplicate the actual machine system and its response. The test-stand rotating speed may also, by necessity, differ significantly from machine operating speeds.
Sometimes all these differences are not significant, at other times they are highly significant.
For these reasons (and for reasons of time, cost and convenience) the field balance method is often preferred and may yield superior results. The apt Group welcomes your inquiries.