Yaskawa Varispeed 626M5 - Manual (Page 40)

2.5 Motor Installation Precautions
2 -11
2.5.3 Coupling Motor and Machinery
Consider the following conditions when coupling the Motor with the machinery.
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Direct Coupling
Couple the Motor with the machinery so that the center of the motor shaft and that of the machinery shaft
are on a straight line. Insert a liner for adjustment, if necessary. If the center of the motor shaft does not
coincide with that of the machinery shaft, unnecessary torsion will be imposed on the motor shaft and ma-
chinery shaft. As a result, the bearings may wear out or break quickly.
Fig 2.13 Direct Coupling Precision of Motor and Machinery
Use the coupling so that a axial load is not imposed on the motor shaft.
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Belt Coupling
Check that the motor shaft is parallel to the machinery shaft and that the line connecting the centers of the
pulleys and the shafts are at right angles to each other. The radial load imposed on the motor shaft edge
must not exceed the permissible value specified in 14.2.5 Tolerance Radial Loads.
Be sure that no axial load is imposed on the motor shaft.
If the angularity of the belt is improper, the belt will vibrate or slip. If an excessive radial load is imposed
on the motor shaft, the motor bearings will be adversely affected and the service life of the bearings will
be decreased.
Check that the angle of contact of the belt and pulley will be 140° or more, or otherwise the belt may slip.
S If C is more than 1,000 (39.4) mm (39.4 inches), d/C < 1/1000
S β < 1/3°
S If C is 1,000 mm (39.4 inches) or less, d < 1 mm (0.039 inches).
Machinery shaft
Motor shaft
Belt
d
C
C
β
φ
Fig 2.14 Belt Installation
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Gear Coupling
Check that the motor shaft is parallel to the machinery shaft and that the centers of the gears are engaged
properly. Refer to 14.2.6 Motor Total Indicator Readings for the precision of the peripheral parts connect-
ing to the motor shaft. The gears may grate if they do not engage properly.
Be sure that no axial load is imposed on the motor shaft.
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Mounting a Pulley or Gear to the Motor Shaft
When mounting a pulley or gear to the motor shaft, consider the mounting balance of the Motor. The dy-
namic balance of the Motor is kept with a half key (for motors with a key way), which is a half as thick
as the key (T) specified in the motor shaft dimensional drawing. The Motor rotates at high speed and a little
imbalance in the mechanism may cause the motor to vibrate.
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Tolerance A: 0.03 m (0.0012 inches) max.
Level
A
B
Surface irregularity B: 0.03 mm (0.0012 inches) max.