As the core equipment for laboratory separation and purification of samples, high-speed freeze centrifuges have both high-speed (usually up to 10000-30000 rpm) and low-temperature temperature control (usually reduced to -40 ℃) functions, and are widely used in fields such as biopharmaceuticals, clinical testing, and environmental monitoring. However, in long-term high-frequency use, equipment is prone to malfunction due to improper operation, lack of maintenance, or aging of components, which not only affects the progress of experiments but may also lead to sample damage or safety risks.
This article summarizes six common faults of high-speed cryogenic centrifuges, providing practical guidance from four aspects: fault symptoms, core causes, step-by-step solutions, and preventive measures, to help laboratory personnel efficiently troubleshoot and quickly solve problems.
1、 Startup failure: The device is unresponsive or immediately shuts down after startup
（1） Fault phenomenon
After pressing the start button, the device has no response (the display screen does not light up, the fan does not turn); Or it may shut down immediately upon startup, and some devices may emit alarm sounds (such as buzzing prompts), and the display screen may show fault codes such as "Err1" and "startup failure".
（2） Core reasons
Power supply issues: poor contact of power sockets, damaged power cords, or tripped circuit breakers;
Safety protection trigger: The door cover is not fully closed (the equipment is equipped with a door cover interlock device, and starting is prohibited if it is not tightly closed), the rotor is not installed correctly (the rotor buckle is not tightened or the model is not matched);
Electrical component failure: damage to the main control circuit board, malfunction of the start switch, or loose motor wiring.
（3） Step by step processing plan
Check the power supply line: First check if the power socket is powered on (other devices can be plugged in for testing), replace the socket and try again; Check if the power cord is damaged or broken again (with a focus on the connection between the plug and the wire body). If it is damaged, immediately replace the original power cord (to avoid using non compatible cables that may cause unstable current); Finally, check if the corresponding circuit breaker in the laboratory distribution box has tripped. After tripping, check if the equipment is short circuited and confirm that there are no abnormalities before closing.
Check the safety interlock device: Open the equipment door cover, clean the door cover sealing ring (if there is dust or sample residue, it will affect the sealing), and re close the door cover with force to ensure that a "click" locking sound is heard; Remove the rotor and check if the bottom buckle of the rotor matches the main shaft groove (different types of rotors cannot be mixed). Align the rotor with the main shaft and gently lower it. Rotate it clockwise until the buckle is fully tightened (some equipment needs to be fixed with a special wrench).
Testing electrical components: If the above steps are ineffective, turn off the power and open the equipment side cover (operated by professionals to avoid electric shock), check whether the motor wiring terminals are loose (tighten with a screwdriver), and whether the starter switch wiring is loose; If you suspect a fault in the main control circuit board, you can use the replacement method to test (replace the same type of circuit board and start the equipment), confirm the fault, and contact the manufacturer for repair (do not disassemble the circuit board yourself).
（4） Preventive measures
Before each use, check the integrity of the power cord and the closed status of the door cover. After installing the rotor, manually rotate it lightly to confirm stability; Regularly (every 3 months) check the electrical wiring terminals to avoid looseness caused by vibration.
2、 Abnormal speed: unable to reach the set speed or large speed fluctuation
（1） Fault phenomenon
After starting, the speed slowly increases and still cannot reach the set value (such as setting 15000 rpm, the actual maximum is only 12000 rpm); Or during operation, the speed fluctuates intermittently, with the display screen speed fluctuating by more than ± 500 rpm, accompanied by slight vibration of the equipment.
（2） Core reasons
Load imbalance: The weight difference of the sample centrifuge tube is too large (exceeding the allowable imbalance of the equipment, usually ≤ 0.5g);
Rotor problems: rotor aging (such as cracks on the rotor surface), foreign objects in the rotor cavity (such as residual sample debris);
Motor malfunction: worn carbon brushes (applicable to brushed motors), insufficient or damaged lubrication of motor bearings;
Speed sensor malfunction: The sensor is covered with dust or the wiring is loose, making it unable to accurately detect the speed.
（3） Step by step processing plan
Adjust load balancing: After shutdown, remove all centrifuge tubes and weigh them one by one with an electronic balance to ensure that the weight difference of centrifuge tubes in the same group is ≤ 0.2g. If it is a multi tube rotor, it should be placed according to the principle of "symmetrical placement" (such as a 6-hole rotor, the empty tube should be placed symmetrically with the sample tube) to avoid one-sided weight deviation.
Check the status of the rotor: visually inspect the surface of the rotor for cracks and deformations (with a focus on checking the edges and hole walls of the rotor). If there are cracks, stop immediately (aging rotors pose a risk of bursting); Clean the foreign objects inside the rotor cavity with a soft bristled brush and wipe them clean with anhydrous ethanol (to avoid foreign objects affecting the rotor's rotational balance).
Maintenance of motor components: For brushed motors, open the motor end cover after power off and remove the carbon brush. If the carbon brush is worn to a length ≤ 5mm (the original length is usually 10-15mm), it needs to be replaced with a carbon brush of the same model; For brushless motors, check if there is any abnormal noise from the bearings (if there is a "rustling" sound during rotation). Special high-temperature lubricating grease can be added (ordinary butter cannot be used as it will affect performance due to high temperature melting); If the bearing is damaged, it needs to be replaced by a professional.
Clean the speed sensor: Find the speed sensor inside the device (usually located near the motor, with a metal probe), use a dust-free cloth dipped in anhydrous ethanol to wipe the surface of the probe, check if the sensor wiring is loose, re plug it, and start the device for testing.
（4） Preventive measures
Strictly balance the weight of the centrifuge tube before each sample installation to avoid overloading operation (the maximum load of the rotor must meet the requirements of the equipment manual); Clean the rotor and speed sensor after every 50 uses, and perform comprehensive maintenance on the motor once a year.
Refrigeration malfunction: unable to cool down or slow cooling rate
（1） Fault phenomenon
After activating the cooling function, the temperature value on the display screen does not decrease (if set to -20 ℃, the actual temperature remains at room temperature); Or the cooling rate may significantly slow down (normally it takes 30-40 minutes to drop from room temperature to -20 ℃, and more than 1 hour in case of malfunction), and some devices may display codes such as "cooling fault" and "temperature exceeding limit".
（2） Core reasons
Refrigeration system issues: refrigerant leakage (long-term use leading to pipeline aging), condenser blockage (dust and hair accumulation affecting heat dissipation), compressor failure (unable to function properly);
Temperature sensor malfunction: The accuracy of the sensor decreases or is damaged, causing the device to misjudge the temperature;
Door sealing issue: The door cover sealing ring is aging, deformed, or damaged, resulting in refrigerant leakage.
（3） Step by step processing plan
Cleaning the condenser: After stopping the machine, disconnect the power supply and locate the condenser on the side or back of the equipment (which appears to be a metal heat sink). Use compressed air (pressure ≤ 0.3MPa) to blow from the inside out to remove surface dust; If there is a lot of oil stains, you can use a soft bristled brush dipped in neutral detergent to gently scrub, air dry and restart the equipment.
Check the status of the door seal: After closing the door cover, insert an A4 paper into the gap between the door seal and the box. If it can be easily removed without resistance, it indicates poor sealing of the door seal; Remove the aging sealing ring and replace it with a new sealing ring of the same model (ensure no distortion and tight fit during installation); If the sealing ring is only slightly deformed, heat a hair dryer (at low temperature) and blow it towards the deformed area for 3-5 minutes to restore it to its original state.
Check the refrigeration system and sensors: If the temperature cannot be lowered after cleaning, contact the manufacturer's after-sales personnel to check the refrigerant pressure (the normal pressure range should refer to the equipment manual, such as R404A refrigerant static pressure of about 0.8-1.2MPa). If the pressure is too low, it indicates a leak and refrigerant needs to be checked and replenished; For temperature sensors, comparative testing can be used (measuring the temperature inside the chamber with a standard thermometer, comparing it with the displayed value, and replacing the sensor if the deviation exceeds ± 2 ℃).
（4） Preventive measures
Clean the condenser once a month to avoid stacking debris around the equipment (with a reserved heat dissipation space of ≥ 30cm); When opening and closing the door cover, operate gently and avoid pulling the sealing ring with force. Replace the sealing ring every 2 years.
Abnormal vibration and noise: severe vibration or excessive noise during operation
（1） Fault phenomenon
The equipment may shake noticeably during operation, and items placed on the table may be knocked over; Simultaneously accompanied by abnormal noise (such as buzzing, friction, or impact), the decibel level of the noise exceeds the specified value in the equipment manual (usually normal operating noise ≤ 65dB).
（2） Core reasons
Unstable placement of equipment: uneven tabletop or uneven equipment feet;
Unbalanced rotor: eccentric installation of the rotor, asymmetric placement of the centrifuge tube, or deformation of the rotor itself;
Mechanical component wear: motor bearing damage, spindle bending, or rotor buckle wear.
（3） Step by step processing plan
Leveling equipment: Place a level on the top table of the equipment to check the level status; If it is uneven, adjust the foot screw at the bottom of the equipment (rotate the screw clockwise to raise and counterclockwise to lower) until the level bubble is in the center position; At the same time, ensure that the countertop is sturdy (not placed on wooden or unstable countertops) to avoid countertop resonance.
Inspect the rotor and load: After stopping the machine, remove the rotor and check for any deformation (such as uneven rotor end faces). If there is any deformation, replace the rotor; When reinstalling the sample, ensure that the centrifuge tube is symmetrically placed with a weight difference of ≤ 0.2g, and that the liquid level of the sample inside the centrifuge tube is consistent (to avoid center of gravity deviation due to liquid level differences); When installing the rotor, ensure that it is completely concentric with the main shaft and there is no eccentricity.
Check mechanical components: After power off, rotate the motor shaft by hand. If you feel any jamming or abnormal noise, it indicates that the motor bearing is damaged and needs to be replaced; Check whether the spindle is bent (visually observe whether the spindle is straight, or measure the radial runout of the spindle with a dial gauge, with a normal runout of ≤ 0.05mm). If it is bent, the spindle needs to be repaired or replaced by the manufacturer; Check if the rotor buckle is worn (if the buckle is loose, displacement will occur when the rotor rotates), and replace the buckle if it is severely worn.
（4） Preventive measures
Choose a flat and sturdy platform for equipment installation, and check the rotor status and load balance before each use; Check the motor bearings every 100 hours of operation and regularly add specialized lubricating grease.
Alarm fault: The display screen shows an alarm code and the equipment is stopped
（1） Fault phenomenon
The device suddenly shuts down during operation, and specific alarm codes (such as "Err2", "overspeed alarm", "temperature alarm", etc.) appear on the display screen. Some devices are accompanied by buzzing prompts, and the meaning of different manufacturer codes may be different, but common alarm types are concentrated in overspeed, overtemperature, imbalance, etc.
（2） Core reasons
Overspeed alarm: The speed exceeds the maximum allowable speed of the equipment (such as the maximum rotor speed of 20000 rpm and the actual speed exceeding 21000 rpm), and the speed sensor is faulty;
Overtemperature alarm: The temperature inside the chamber exceeds the set range (such as the temperature during cooling is higher than 0 ℃ or the temperature during heating is higher than 60 ℃), and the temperature sensor is faulty;
Unbalance alarm: The load imbalance exceeds the allowable value of the equipment (usually ≤ 0.5g), and the imbalance detection sensor is faulty.
（3） Step by step processing plan
Interpretation of alarm code: Firstly, refer to the equipment manual and determine the type of fault based on the alarm code (for example, a certain brand of equipment "Err2" represents imbalance alarm, "Err5" represents overtemperature alarm); If the manual does not provide clear instructions, you can contact the manufacturer's technical support to provide guidance on equipment models and alarm codes.
Targeted processing:
Overspeed alarm: Check if the set speed exceeds the maximum rotor speed (ensure that the rotor model matches the set speed, such as low-speed rotors that cannot be used for high-speed operation); If the setting is normal, check if the speed sensor is contaminated, clean the sensor, and restart the device;
Overtemperature alarm: If the temperature exceeds the limit during refrigeration, follow the "refrigeration fault" processing steps to troubleshoot (clean the condenser, check the refrigerant, etc.); If overheating occurs during heating, check if the heating tube is short circuited and if the temperature sensor is functioning properly;
Unbalance alarm: Rebalance the load to ensure symmetrical placement and consistent weight of the centrifuge tubes, and check if the wiring of the imbalance detection sensor is loose.
Reset device: After processing is complete, turn off the device power, wait for 5-10 minutes, then turn it back on, press the "Reset" button to clear the alarm code, and restart the device for testing.
（4） Preventive measures
Strictly set operating parameters according to the rated speed of the rotor to avoid overloading or overspeed use; Regularly calibrate temperature sensors and speed sensors (at least once a year) to ensure detection accuracy.
Sample leakage: centrifugal tube rupture or sample overflow to rotor
（1） Fault phenomenon
After the operation is completed, opening the equipment door cover reveals liquid residue in the rotor chamber, the centrifuge tube ruptures (fragments remain in the rotor hole), or the sample overflows from the centrifuge tube, contaminating the rotor and chamber wall.
（2） Core reasons
Centrifugal tube problems: poor quality of centrifugal tubes (such as insufficient speed resistance level), aging of centrifugal tubes (excessive use), loose or damaged cover of centrifugal tubes;
Improper operation: Excessive sample loading (exceeding 2/3 of the centrifuge tube volume, causing liquid overflow during high-speed rotation), asymmetric placement of centrifuge tubes resulting in uneven force distribution;
Rotor problem: There are burrs or damages on the inner wall of the rotor hole, and the centrifuge tube is scraped during rotation.
（3） Step by step processing plan
Cleaning up leaks: After stopping the machine, disconnect the power supply, wear gloves and goggles, remove the rotor, and use tweezers to remove broken centrifuge tube fragments (to avoid scratching hands); Wipe the rotor holes and chamber walls with anhydrous ethanol or specialized disinfectants to remove sample residues (if the sample is corrosive, rinse with plenty of water before disinfection); After cleaning, dry the rotor and cavity wall to avoid residual liquid causing rust.
Investigate the cause and handle it: Check whether there are cracks or aging in the remaining centrifuge tubes, and replace them with new ones if necessary (choose centrifuge tubes that match the equipment speed, such as high-speed centrifugation, which requires centrifuge tubes that can withstand 15000 rpm or more); Ensure that the centrifuge tube cover is tight and free from looseness or damage; Check whether the inner wall of the rotor hole is smooth. If there are burrs, they can be lightly sanded with fine sandpaper (operated by professionals), or the rotor can be replaced.
Re operation: Replace the qualified centrifuge tube, control the sample loading (not exceeding 2/3 of the centrifuge tube volume), place the centrifuge tube according to the principle of symmetry, ensure weight balance, and restart the equipment.
（4） Preventive measures
Choose centrifuge tubes produced by reputable manufacturers that match the equipment speed to avoid the reuse of disposable centrifuge tubes; Control the liquid level height during sample loading, and check the sealing of the centrifuge tube after sealing it tightly; Before each use, check the condition of the inner wall of the rotor hole to avoid foreign objects or burrs.
Conclusion
The troubleshooting of high-speed cryogenic centrifuges should follow the principle of "investigating simple causes first, and then dealing with complex components". Priority should be given to checking basic issues such as power supply, load, and installation before delving deeper into repairing electrical or mechanical components. In daily use, regular maintenance (cleaning, lubrication, calibration) and standardized operation (balancing load, not exceeding speed operation) are key to reducing failures. If encountering complex faults (such as compressor damage or spindle bending), do not disassemble them by yourself. Contact the manufacturer's after-sales personnel in a timely manner to avoid further equipment damage or safety accidents caused by improper operation. Through scientific troubleshooting and preventive maintenance, the service life of equipment can be effectively extended, ensuring the stability and safety of experiments.