3.1.3. ALIGNMENT / LEVELLING USING WEG MOTOR SHIMS
The electric motor must be accurately aligned with the driven machine, particularly in cases of direct coupling. An incorrect alignment can cause bearing damage, vibrations, shaft breaking and brushes sparking.
The best way to ensure correct alignment is to use dial indicator placed on each coupling half, one reading radially and the other axially.
In this way, simultaneous readings can be informed and one can check any parallel (figure 8) or concentricity deviations (figure 9) by rotating the shaft. The dial indicator should not exceed 0.05mm. If the operator is sufficiently skilled, he can obtain alignment with clearance gauge and a steel ruler, providing that the couplings be perfect and centered (figure 10).
A measurement at 4 different points of the circumference should not give a reading difference larger than 0.03mm. Figure 8 – Angular Clearance (Parallelism).
On the alignment/leveling using Weg Motor Shims it is important to take into consideration the effect of the temperature over the motor and driven machine. The different expansion levels of the coupled machines can modify the alignment/leveling during motor operation.
After the set is perfectly aligned either at cold or at hot, motor must be bolted, as shown in figure 11. There are instruments which use visible laser ray added by specific computer programs that can perform and ensure high precision alignment.