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Star Republic: Guide for Biologists

Centrifuge

1. Carefully balance you samples. For microcentrifuges, make a series of labeled microcentrufuge tubes filled with 50 ml to 1,500 ml (colored) water as balancers.

Better balancing is required for ultracentrifuges.

2. Immediately stop the centrifuge if it makes loud noise, re-balance you samples.

3. For centrifuges with removable rotors, make sure the rotor is compatible with the centrifuge.

4. For each rotor, there is a maximum speed limit. Don't excess the speed limit.

5. Convert RCF to RPM.

6. Never start centrifugation when the rotor is not secured.

7. Never centrifuge radioactive or hazardous samples in open tubes.

8. When not in use, it is preferable to remove rotors and invert to prevent erosions (except for most microcentrifuges --- keep the lid open).

9. When samples need to be centrifuged at low temperature, cool down rotor before place in samples.

10. Centrifuges with brush motors need to have the rotor brush changed periodically. Induction motors does not need brush, but are more expensive and may have more electronic problems.

Ultracentrifuges should be serviced regularly.

Change motor brush

1. Make sure the centrifuge do have motor brushes. Unplug the centrifuge.

2. Locate the motor brush. Usually you need to remove the rotor and accessories. On some models you may need to remove the rotor boot.

3. There are usually one brush on each side of the drive motor. Remove the brush caps. Be careful not drop any small parts.

4. Carefully remove the brushes and remember the order of the carbon contactor, the spring, the copper connector wire, and the end cap.

5. Clean dust, replace with new parts in the same order.

7. Put the rotor back on and test first at a low speed.