Pulley And Belt Coupling; Coupling Of Sleeve Bearing Motors - WEG W22 Premium E3 Manual De Instalación, Operación Y Mantenimiento

www.weg.net

6.4.3. Pulley and belt coupling

Pulleys and belts are used when speed increase or reduction between motor shaft and driven load is required.
Excessive belt tension will damage the bearings and cause unexpected accidents such as breakage of
the motor shaft.
To prevent the buildup of static electricity in the belt drive system, use only properly grounded belts in
conductive construction.

6.4.4. Coupling of sleeve bearing motors

Motors designed with sleeve bearings must be operated with direct coupling to the driven machine or a
gearbox. Pulley and belts can not be applied for sleeve bearing motors.
Motors designed with sleeve bearings have 3 (three) marks on the shaft end. The center mark is the indication
of the magnetic center and the 2 (two) outside marks indicate the allowed limits of the rotor axial movement, as
shown in Figure 6.9.
The motor must be so coupled that during operation the arrow on the frame is placed over the central mark
indicating the rotor magnetic center. During start-up, or even during operation, the rotor may freely move
between the two outside marks when the driven machine exerts an axial load on the motor shaft. However,
under no circumstance, the motor can operate continuously with axial forces on the bearing.
For coupling evaluation consider the maximum axial bearing clearance as shown in Table 6.1.
The axial clearance of the driven machine and coupling influence the maximum bearing clearance.
Bearing size
* For Motors in accordance with API 541, the total axial clearance is 12.7 mm
The sleeve bearings used by WEG were not designed to support axial load continuously.
Under no circumstance must the motor be operated continuously at its axial clearance limits.
94 Manual of Electric Motors
Figure 6.9 - Axial clearance of motor designed with sleeve bearing
Table 6.1 – Clearance used for sleeve bearings
9*
11*
14*
18
Axial Clearance
Total axial clearance (mm)
3 + 3 = 6
4 + 4 = 8
5 + 5 =10
7,5 + 7,5 = 15