Sartorius SIGMA 3-18 and 3-18K
Sartorius · Model SIGMA 3-18 and 3-18K
SIGMA 3-18. Universal table top centrifuge; speed range up to 16.000 rpm. Operation with various fix-angle and swing-out rotors available. Maximum capacity of 4 x 250 ml down to microtubes with different adapters in the same bucket. Maintenance-free induction drive motor. A microcontroller controls speed, time, temperature and gravitational field. 10 quadratic and 10 linear preset deceleration and acceleration curves. Any curve can freely be programmed and displayed grafically. Suitable for low speeds e.g. for cell sedimentation, accuracy +/– 1 rpm. Magnetic rotor identification prevents the rotor from overspeeding. Stainless steel bowl. Imbalance switch. Produced according to national and international safety regulations. Motorized lid lock SIGMA 3-18 K. Technically largely identical to 3-18 but with built-in refrigeration system. Suitable for low speeds e.g. for all sedimentation. Higher speed for faster separations. Possibility of precooling the rotors during standstill. Refrigerated CFC-free (R 134 a). Suitable for sedimentation of temperature sensitive substances.
Key tips
- ·Run QC controls before trusting any repair - an analyzer that passes self-test can still report clinically wrong results.
- ·Rule out a reagent lot change before opening the instrument - it can look exactly like a hardware fault.
- ·Centrifuge rotors have a hard retirement age/cycle limit regardless of visible condition - don't eyeball it.
Typical Failure Modes
Compiled for this model from its own documentation and established engineering knowledge for this equipment class - not from a verified service record. Confirm against the manufacturer's service manual.
Will not start / error at start
HighSymptoms: Error code, run will not begin, or aborts shortly after start.
Root cause: Set speed exceeds the rotor maximum, an imbalanced load, the lid / door not locked, an unapproved rotor, or a drive / control fault.
Will not reach speed / excessive noise or vibration
MediumSymptoms: Slow spin-up, rumble, or vibration during a run.
Root cause: Load imbalance, worn drive / motor bearings, a worn drive coupling, or (older units) worn motor brushes.
Timer / speed inconsistency
MediumSymptoms: Run ends early / late, or RPM does not match the setting.
Root cause: Tacho / speed-sensor drift or a control-board fault.
Lid / door will not open or lock
MediumSymptoms: Lid-lock error, will not open after a run, or will not lock to start.
Root cause: Lid-lock solenoid / switch fault, or a run still winding down.
Rotor / bucket wear or corrosion
MediumSymptoms: Visible corrosion, cracks, or a bucket that will not swing; imbalance trips.
Root cause: Rotor / bucket ageing - a safety-critical wear item with a use-life limit.
Serviceable Parts & Consumables
Serviceable items for this model, compiled from its documentation and engineering knowledge for this equipment class. Service class and relative cost are estimates, not manufacturer figures; no part numbers are given. Confirm intervals and pricing against the manufacturer.
Drive / motor bearings & coupling
Class Major service partRel. cost $$$R&R Difficult
Lid-lock solenoid / switch
Class Major service partRel. cost $$R&R Moderate
Speed sensor / control board
Class Major service partRel. cost $$R&R Moderate
Motor brushes (older units)
Class Periodic replacementRel. cost $R&R Moderate
Rotor / bucket set & O-rings
Log rotor runs; retire per the manufacturer's rotor-life programme.
Class Major service partRel. cost $$$R&R Easy
| Part | Service class | Relative cost | R&R difficulty |
|---|---|---|---|
| Drive / motor bearings & coupling | Major service part | $$$ | Difficult |
| Lid-lock solenoid / switch | Major service part | $$ | Moderate |
| Speed sensor / control board | Major service part | $$ | Moderate |
| Motor brushes (older units) | Periodic replacement | $ | Moderate |
| Rotor / bucket set & O-rings Log rotor runs; retire per the manufacturer's rotor-life programme. | Major service part | $$$ | Easy |
Relative cost: $ lowest · $$$$ highest service-part cost for this equipment class. Not a price.
PM Checklist
Preventive-maintenance tasks typical of this equipment class. Perform to the manufacturer's procedure and your facility's policy - this is general reference, not a schedule for this specific unit.
- ·Daily QC controls run and reviewed
- ·Calibration verification per assay
- ·Routine cleaning and decontamination
- ·Scheduled reagent-path and pump-tubing maintenance
Troubleshooting Approach
A starting sequence for this model, compiled from its documentation and engineering knowledge for this equipment class. Follow the manufacturer's service documentation for the actual procedure.
Symptom: Will not start or errors at start
- Confirm the set speed does not exceed the fitted rotor's maximum and the rotor is approved and seated.
- Rebalance the load - opposing positions evenly loaded and paired.
- Confirm the lid / door latches and the lock engages.
- Look the fault code up in the manual and follow the remedy.
- Functional-check speed and timer after any repair.
Symptom: Noisy / vibrates / will not reach speed
- Rebalance and re-run empty to confirm.
- Spin the rotor by hand and feel for bearing roughness.
- Inspect the drive coupling and (older units) the motor brushes.
- Replace the worn component.
- Verify speed with a tachometer and confirm smooth running.
Typical Location
Where this class of equipment is typically deployed - general reference, not this unit's own placement record.
- Central / core laboratory
- Point-of-care testing stations
- Blood bank
- Microbiology lab
Documents & Manuals
Related calculators
From BioLab, for work done with this kind of equipment.
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