Danfoss Turbocor TT Series, Service Manual

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5.2.3 Bearing Fault Troubleshooting
Table 5-9 Bearing Status
Bearing Fault
Description Trigger
Method
Troubleshooting
Startup
Calibration Check
Fault INS
l
During compressor start-up, the stored bearing calibration is verified. Indicates that the calibration
failed during compressor start-up. Manually calibrate the bearings and save to EEPROM, cycle the
power.
l
Review the calibration report to determine conditions related to the fault.
l
If the bearings cannot pass calibration after three (3) attempts, verify the PWM (refer to Section
4.28.3 PWM Verification on page 226), bearing sensors (refer to Section 4.30.3 Bearing Sensor
Verification on page 236), and bearings (refer to Section 4.29.3 Bearing Verification on page 230).
Bearing
Displacement
Fault INS
l
The shaft position has been measured outside the bearing displacement maximum in one of the
five bearing positions.
l
This fault can be the result of system-related issues, such as EXV control issues (i.e., starving the
evaporator or pumping liquid), operating at the surge line, check valve failure, or IGV failure.
l
Review Fault and Event Log details to determine conditions related to the fault. Using the
Compressor Configuration tool, set the Control Mode to Manual. Using the Compressor Monitor,
levitate the shaft and record the bearing forces. Greater than 2A indicates a bearing issue.
l
Manually calibrate the bearings, save to EEPROM and identify if bearing forces improve.
l
If the bearings cannot be calibrated after three attempts, verify the PWM (refer to Section 4.28.3
PWM Verification on page 226), bearing sensors (refer to Section 4.30.3 Bearing Sensor Verification
on page 236) and bearings (refer to Section 4.29.3 Bearing Verification on page 230).
l
Review the calibration report to determine conditions related to the fault. Refer to Section 5.3.5
Calibration Report Analysis on page 266.
Bearing
Overcurrent Fault INS
l
Indicates that the current drawn by the bearing exceeds the maximum amps in one of the five (5)
bearing positions. Using the
Compressor Configuration Tool , set the Control Mode to Levitate Only
Mode. Using the Compressor Monitor , levitate the shaft and record the bearing forces. Greater than
2A indicates an issue.
l
Manually calibrate the bearings, save to EEPROM and identify if bearing forces improve. If the
bearings cannot be calibrated after three (3) attempts, verify the PWM (refer to Section 4.28.3
PWM Verification on page 226), bearing sensors (refer to Section 4.30.3 Bearing Sensor Verification
on page 236) and bearings (refer to Section 4.29.3 Bearing Verification on page 230).
l
Review the calibration report to determine conditions related to the fault. Refer to Section 5.3.5
Calibration Report Analysis on page 266.
5.3 Bearing Calibration
5.3.1 When to Calibrate the Bearings
5.3.1.1 Calibration when Commissioning
A bearing calibration can be performed at commissioning for the purpose of comparing current calibration values to
factory saved calibration values. After the calibration has been performed, a calibration report should be created and
saved for future comparison. There is no requirement to save the calibration to EEPROM when commissioning the
compressor.
M-SV-001-EN Rev. H-1/23/2023 Page 263 of 294