Siemens induction motors- generators cgii User Manual

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Check for vertical alignment (parallelism) of coupled 
drive as follows: 
1.  Operate unit until normal temperature is reached 

(may require several hours). 

2.  Shut down motor and lock out switch. 
3.  Mount dial indicator as in Figure 2. 
4.  Rotate shaft, noting readings at 0°, 90°, 180°, and 

270° (both sides, top, and bottom).  If within 0.002 
inch total indicator reading, or other limit specified 
by the factory, unit is satisfactory for operation. 

5.  If not within limits, add or remove shims as 

required to raise or lower motor. 

6. If shims are changed for high temperature 

operation, repeat alignment procedure to extent 
necessary to assure proper alignment.  Document 
readings for warranty information. 

 

 

Figure 2.  Check of Vertical Alignment 

 

The standard unfiltered housing vibration limits 
measured at no load, uncoupled, and with rigid 
mounting are as follows based on the requirements of 
NEMA MG1-7.8. 

 

 

After alignment is complete and foot mounting bolts are 
tight, run motor at no load (or minimum possible).  
Check for vibration.  If excessive vibration exists and 
the alignment is acceptable, check foot plane by 
loosening one drive end-mounting bolt at a time as 
detailed below.  This is to be documented for warranty 
information.  When resiliently mounted, allowed levels 
are 25% higher. 

 
Completing Mechanical Installation 
After controlling rotor end float and establishing 
accurate alignment, it is recommended to drill and 
ream the foundation plate and motor feet together for 
dowel pins.  (See Doweling).  
Recheck parallel and angular alignment before bolting 
the coupling together.  Motor shaft should be level 
within 0.03 inch after alignment. 
 

Doweling the motor (and driven unit) accomplishes the 
following: 
 
1. Restricts 

movement. 

2.  Eases realignment if motor is removed from base. 
3.  Temporarily restrains the motor, should mounting 

bolts loosen. 

 
Inserting Dowel Pins 
The following procedure is recommended: 
 
a.  Check the alignment after the unit has been in 

operation approximately one week.  Correct as 
necessary. 

b.  Using pre-drilled dowel holes in motor feet as 

guides, drill into the mounting base. 

c.  Ream holes in the feet and base to the proper 

diameter for tapered dowel pins. Clean out the 
chips. 

d. Insert 

dowel 

pins. 

 

If force feed lubrication is used, flush lubrication lines 
thoroughly to make sure the lines are clean before 
connecting lines to bearing housings.  Be sure that 
bearing cavities are filled with oil to the proper level 
before starting.  See motor outline drawing to 
determine proper oil level.  Be sure that proper oil 
pressure and flow are provided by the supply system.  
Verify that the oil drain flow agrees with the factory 
requirements.  The orientation and size of oil drain 
piping supplied with the motor must not be altered.  Oil 
drain piping should be of the same size or larger from 
the motor piping to the oil sump.  Piping must slope 
downward. Pressure build up in the drain line between 
the oil sump and the motor bearing housing can lead to 
oil leakage.  Document readings for warranty 
information.