4. Standards for AC motors
Grundfos Motor Book
IEC 60072-1 Measurement of tolerances
Parallelism of keyway to shaft axis The tolerance for parallelism has to comply with the table below. Parallelism of keyway to shaft axis is defined as the limit variation between the keyway median longitudinal plane and the theoretical keyway median longitudinal plane which contains the shaft axis. The distance between those two planes, taken at each end of the usable length of the keyway, has to lie within the limit values below.
EB (EC) nominal (mm)
Limit of deviation from theoretical position at extreme ends of EB (EC) (mm)
≤ 100 > 100
≤ 0.05 ≤ 0.0005 • EB (EC)
Keyway longitudinal plane Shaft axis and theoretical keyway median longitudinal
Deviation from theoretical position
Lateral displacement of keyway The tolerance for lateral displacement is 0.1 mm. Lateral displacement of keyway is defined as the greatest deviation at any point along the usable length of keyway. This deviation is the distance from the centre-line of the keyway to the plane through the centre-line of the shaft end perpendicular to the true position of the bottom of the keyway.
76 Grundfos Motor Book
Lateral displacement
Shaft centre line plane
Centre line of keyway