KnowledgeBase

Couple6 Backlash – T-1290 Target Only

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Couple6 uses the Vertical Offset and Vertical Angular values to calculate the misalignment of the motor shaft axis of rotation (AOR) relative to the driven unit’s AOR. By using only the Vertical Axis for taking data, Couple6 is insensitive to coupling backlash and it takes a severe case of backlash to produce a measureable impact on the accuracy of the data. In almost all cases, backlash does not affect the accuracy to any measurable degree. After taking the data, Couple6 uses a sophisticated curve-fitting algorithm that determines the misalignment. The software then uses this information to calculate display offsets and applies them to the raw data to show the true misalignment

Excess Backlash Detector (S-680 T-1290 Target Only)

 If Excess Backlash Detected displays at the bottom of the Measurement Results Screen, Couple6 has detected excess backlash in the coupling. This could cause problems aligning the Horizontal Offset in the Move screen because the T-1290 (or any other laser alignment system) cannot detect the difference between a Horizontal Offset Move and a slight rotation of the motor shaft relative to the pump shaft.

When aligning a motor with this condition, a message displays in the Step 5: Move Screens if Couple6 detects a >3° rotational move.  The message directs the user to rotate the laser/target to 3:00 or 9:00 for the Horizontal Move or retake the data and leave the laser/target at 3:00 or 9:00.

Backlash Detector (T-1290 Only)

 The T-1290 target offers the capability to detect backlash at the coupling.  During Step 4: Auto Sweep data collection, Couple6 determines if there is too much variability in the Horizontal Offset value (an indicator of coupling backlash). If so, Couple6 monitors the rotation angle in the Step 5: Move Screens to determine if it is necessary to perform the Horizontal Move while the laser/target are at 3:00 or 9:00.  If Couple6 detects too much of a change in the rotation axis (more than ± 5 degrees) during the Vertical Move, a warning message displays, indicating rotation to 3:00 or 9:00 is necessary to perform the Horizontal Move. The other option is to retake the data in Step 4, leaving the laser/target at 12:00, and retry the horizontal part of the alignment.

The reason for the Excess Backlash Detected message is that the T-1290, or any other laser system, cannot detect the difference between a Horizontal Offset move and a slight rotation of the motor shaft relative to the pump shaft.  This could cause errors aligning the Horizontal Offset in the Move screen.  This potential Horizontal Offset error does not occur when the laser/target are at 3:00 or 9:00.