TL;DR
Grinding noise with metal particles in the oil means gear tooth spalling. Drain and inspect the oil immediately. If metal debris confirms gear damage, the unit needs replacement, not oil top-up.
What you might see
- grinding or crunching noise at running speed
- metal particles in gear oil during oil change
- noise increases under load
- vibration at gear mesh frequency
Likely causes
Gear tooth surface fatigue (pitting or spalling) from operating beyond rated torque or past service life
Inadequate or degraded lubrication accelerating surface fatigue
Contaminated gear oil introducing abrasive particles to the gear mesh
Shock load events exceeding the Movigear rated torque causing instant tooth damage
Required tools
- LOTO kit
- Drain container and clean rags
- Magnet or magnetic pickup tool
- Borescope (optional but useful)
- Torque wrench for drain plug
Safety first
- Secure the driven load against backdrive before locking out the motor.
- Gear oil may be hot at shutdown. Allow 30 minutes to cool before draining.
Procedure
- 1
Lock out the prime mover and verify zero torque on the output shaft before any inspection.
Warning: Secure the driven load mechanically before locking out. A backdrive from the load can cause the gearbox output to rotate when the motor is off. - 2
Drain the gear oil into a clean container and inspect it. Metal particles (shiny flakes or dark magnetic sludge) confirm gear wear. White or milky oil indicates water contamination.[1]
- 3
Use a magnetic pickup or magnet on a rod to check the oil drain plug and reservoir for ferrous metal debris. Significant metal pickup is a stop-use indicator.
- 4
If you have a borescope, inspect the gear mesh area through the oil fill port.
- 5
Review the load history: has the gearbox operated above its rated torque? Has it experienced impact or shock loads? Document findings for the failure analysis.
- 6
If metal debris is significant, tag the unit Out of Service. Do not add fresh oil and continue operating, the gear surface is already damaged and will fail rapidly.[1]
- 7
Order a replacement SEW Movigear unit of the same type code. The full type code is on the nameplate and encodes the gear ratio, motor size, and mounting style.
- 8
When replacing, inspect the driven machine for the overload or shock condition that caused the damage before returning the new unit to service.
Sources
SEW-Eurodrive Movigear Operating Instructions, SEW-Eurodrive
SEW-Eurodrive Movigear Installation and Operating Instructions, gear oil inspection and service criteria (general)
View source
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