A customer specifies that the rotor is to be balanced to 4W/N. Is that the 4W/N Military specification, or the 4W/N API specification?It could make a big difference. And, how do they compare to the ISO 1940/1 specification (G2.5, G1, etc.)? Fortunately, for symmetrical rotors, comparing the various standards is only a matter of a bit of easy algebra. For non-symmetrical rotors, the process gets a little more difficult because each of the specifications handles these cases differently. The other good news is that there are on-line references that provide graphic and tabulated comparisons.
This presentation covers:
- Sleeve bearings
- Geometry/air gap
- Test run
Most service centers balance rotors routinely, with few surprises in the process. There are even technicians who balance rotors so well that the highest velocity readings on the test bed are normally under 0.01 inch/second. It is a great indication of quality when a customer swears that a motor has never run that smoothly. Most of us do not balance fans nearly as often as rotors. The fan balancing tips in this article should be helpful. We'll start with a basic explanation of balancing and then get into balancing tips for fans. Many of these are also applicable to impellers, large sheaves and other rotating parts our customers may ask us to balance.
This article describes machine balancing of the rotating components of motors and generators, primarily rotors and armatures. The methods described here, in general, can be applied to on-site balancing if the rotating component is accessible. The intent is to describe the methods of attaching balance weights, not determining acceptable balance level or the location and amount of correction weight.