Frequent Centrifuge Questions

Frequently Asked Questions

  • My samples are in the machine and I cannot open the lid, how do I get them out?
  • All machines have a mechanical override, you need the tool provided with the centrifuge or a thin piece of metal such as a very thin screwdriver or small Allen key.

    If you don’t have the correct tool and your improvising then your makeshift tool needs to be 1.5mm in diameter and 3cm long. Always ensure centrifuge has stopped and is disconnected from the supply.

    Insert tool into hole. The hole for the mechanical override is in different positions on different centrifuges as follows:

    Micro Centaur Plus & Kestrel Right hand side on main chassis. Push tool in about 3cm.

    Centaur 2 Top centre of lid, 8cm from front. Pivot tool towards you.

    Blue Force 1L Top of the front moulding. Push tool in about 3 cm and pivot to the left.

    Harrier 18/80 To left of the lid opening mechanism, insert tool. Pivot to the right.

    Falcon 6/300 & 6/300R Top of lid 6cm from front. Pivot toward you.

    Cellsep 6/720R Right hand side top of lid, 22cm from the rear. Pivot to the right.

  • The centrifuge shakes around and then shuts off. What is happening?
  • The centrifuge is designed to cut out if an out-of-balance occurs. First check that the buckets are evenly balanced, the maximum allowed is in general about 5g.

    Remove the buckets if it is a swing out rotor and run the centrifuge with just the rotor in place. If the centrifuge now runs smoothly weigh the buckets to ensure they are of equal weight, often the inserts/cushions get mixed up during cleaning, thus making the overall bucket weights uneven.

    Buckets, at times, do not swing out correctly during the run due to dirt or dried grease on the trunnion pins that the bucket sits on. Clean and lubricate trunnions and bucket slots.

    Check that with the buckets on the rotor they swing up to the horizontal position freely, then try the same with tubes in place.  This is because the the tubes may be too long and be catching on the rotor.

  • The centrifuge does not shake about but cuts out while starting to run up.
  • The out of balance detector may be too sensitive. All centrifuges in general will cut out at about 500 to 1000 rpm to prevent damage to the machine if an out of balance is detected. The set up of the out of balance detector will require an engineer.

  • I have a refrigerated centrifuge but the temperature is not going down enough.
  • Often users operate the centrifuge without performing a pre-cool. The motor in the centrifuge generates heat and the cooling comes from the rotor bowl. It is unrealistic to start a centrifuge at ambient temperature and run it at full speed and expect the refrigerator to pull the temperature down to say 3 degrees on a 10 minute run.

    We advise you to run the centrifuge with no samples in the rotor at the required temperature at a low speed such as 800 rpm for 15 minutes to allow the bowl and rotor to get to the set temperature. Then put samples in and run as normal.

  • I have a refrigerated centrifuge and it often has a pool of water in the bowl
  • After use, all refrigerated centrifuges should be left with the lid open to allow the frost on the inside of the bowl to evaporate. If the lid is shut after use, the frost melts and remains in the bowl, this can cause corrosion and is the main reason for damage to the top bearings in the motor or drive assembly. This can be a costly operator error, always leave the lid open.

  • I moved the centrifuge or have just taken it out of the box and it will not run
  • Sometimes the out of balance switch jam’s in transit, try to move the motor and rotor about, just by this action the out of balance switch will reset itself and the problem is resolved.