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Searching for centrifuge acceleration usually means one of two things: how fast the rotor is allowed to speed up and slow down (the acceleration and braking ramp), or the acceleration the sample experiences at speed (relative centrifugal force, RCF). This guide is mainly about the first meaning, which most other pages skip, and it shows manufacturer-published stop times so you can see how much the setting and the rotor change a run.
What centrifuge acceleration means
Short answer: the ramp is the time profile a centrifuge follows to reach its set speed and to come back to rest. RCF is a separate quantity: the acceleration applied to the sample at the set speed, expressed in multiples of g.
Ramp: acceleration and deceleration profiles
Many centrifuges let the operator choose how the rotor accelerates and, more often, how it slows down. Free deceleration (no active braking) lets the rotor coast down; a braking setting shortens the stop time. The sections below show how three Eppendorf and Thermo Fisher Scientific documents describe this.
RCF: acceleration at the sample
RCF is calculated from rotor radius and speed, so the same rpm gives a different g-force in different rotors. For the conversion see RCF vs RPM in centrifugation, and for how rotor geometry affects pelleting time see centrifuge k-factor and pelleting time. For the basic instrument, see what is a centrifuge.
How ramp settings are set up
Settings are defined by the manufacturer and differ by model, so the instrument manual is the authority for any given centrifuge.
Eppendorf 5804/5810 series: levels 0 to 9
The operating manual for the Centrifuge 5804, 5804 R, 5810 and 5810 R (section 6.2, “Setting the acceleration and braking times”) states that acceleration and braking time can be set in levels 0 to 9. Level 9 is preset and gives the shortest acceleration and braking time. Braking level 0 corresponds to free deceleration.
Thermo Scientific accuSpin 8C: standard, soft and brake-off
Thermo Fisher Scientific’s published curves for the accuSpin 8C show one standard acceleration profile and three deceleration profiles: standard, soft and brake-off. The deceleration profile is adjusted with the Curve Key, with the setting shown by LEDs. Thermo states that the profiles are based on a fully loaded rotor at rated voltage and can vary with conditions. Curves are given for fixed-angle and swinging-bucket rotors.
Heraeus Megafuge 16R: curves per rotor
Thermo Fisher Scientific publishes acceleration and deceleration curves for each rotor on the Megafuge 16R. For example, the HighConic II 6×100 rotor takes about 4 min 30 s to reach 9000 rpm and about 28 min to stop; the BIOShield 720 rotor takes about the same 4 min 30 s to reach 5500 rpm and about 26 min to stop. Thermo describes the profiles as an aid to understanding performance with different setups.
Vendor settings compared
| Centrifuge | How the ramp is expressed | Source detail |
|---|---|---|
| Eppendorf 5804/5810 series | Levels 0 to 9 for acceleration and braking | Level 9 = shortest acceleration and braking time; braking level 0 = free deceleration |
| Thermo Scientific accuSpin 8C | One acceleration profile; deceleration standard, soft or brake-off | Selected with the Curve Key; shown by LEDs |
| Heraeus Megafuge 16R | Published curves per rotor | Times to speed and to stop differ by rotor setup (about 28 min vs about 26 min to stop in the two examples above) |
Stop times by rotor: one model, same setting
Eppendorf’s manual (Table 2, 230 V devices, per DIN 58 970) lists approximate deceleration times by rotor for each braking level. The extract below shows the same level giving very different stop times in different rotors.
| Rotor | Level 0 (s) | Level 1 (s) | Level 5 (s) | Level 9 (s) |
|---|---|---|---|---|
| A-4-81 | 532 | 189 | 109 | 31 |
| A-4-62 | 740 | 190 | 110 | 26 |
| A-4-44 | 470 | 300 | 140 | 23 |
| F-34-6-38 | 880 | 370 | 150 | 54 |
| S-4-104 | 680 | 192 | 112 | 32 |
| F-45-30-11 | 240 | 140 | 30 | 18 |
Eppendorf notes these values are guidelines and that considerable fluctuations can occur depending on the condition of the device and the load. Deceleration times for 230 V and 120 V devices are almost identical. The table is an extract: it does not list every rotor or level, so check the full table in the manual for your rotor.
Reading the curves
- Compare the stop time with the speed reached: in the Megafuge examples the acceleration time was the same but the stop times differed.
- Check the conditions stated under the curve. Thermo states its accuSpin 8C curves assume a fully loaded rotor at rated voltage.
- Treat published times as guides. Eppendorf states that load and device condition cause considerable variation.
Safe use basics
Rotor balance matters at every speed and ramp; see centrifuge rotor balancing and safety. Use the rotor and settings the manufacturer specifies for your model, and keep rotor records as described in centrifuge rotor care, inspection and log keeping.
Common mistakes
- Assuming one braking level gives the same stop time in every rotor. The manual table above shows 31 s, 54 s and 18 s at level 9 for three different rotors.
- Confusing the ramp with RCF. The ramp changes how long the rotor takes to reach speed, not the g-force at the set speed.
- Not recording the ramp or profile used. A run log that notes speed, rotor and ramp or profile makes a run easier to repeat.
- Treating a guideline time as exact when the manufacturer calls it approximate.
FAQ
What is centrifuge acceleration?
It can mean the ramp (how quickly the rotor reaches speed and stops) or the RCF at the sample. This guide covers the ramp and links to the RCF explanation.
What does braking level 0 mean on an Eppendorf 5810?
The operating manual states that braking level 0 corresponds to free deceleration, and level 9 is the preset with the shortest acceleration and braking time.
Does the ramp change the RCF?
RCF depends on speed and rotor radius; the ramp governs how the rotor gets to and from that speed.
Why does the same setting stop different rotors at different times?
Eppendorf’s table gives different deceleration times per rotor at the same level (for example level 9: 31 s for A-4-81, 54 s for F-34-6-38). Stop times are rotor-specific.
Sources
- Eppendorf, Centrifuge 5804/5804 R/5810/5810 R operating manual, section 6.2 and Table 2 (PDF copy hosted at genomics.lsu.edu), read 2026-11-08.
- Thermo Fisher Scientific, Fisher Scientific accuSpin 8C acceleration and deceleration curves (knowledge1.thermofisher.com), read 2026-11-08.
- Thermo Fisher Scientific, Heraeus Megafuge 16R acceleration and deceleration curves (knowledge1.thermofisher.com), read 2026-11-08.
