Instruction manual
Operation
Acceleration and deceleration rates
2-18 WX Ultra Series Thermo Scientific
* Minimum time is the time for accelerating or decelerating by the driving motor with maximum 
torque. this time depends on the type of rotor in use.
The following are typical examples of application of acceleration and deceleration rates
Code No.
Acceleration time (minutes) from rest to 
500 rpm
Deceleration time (minutes) from 500 
rpm to rest
9 Minimum time* Minimum time*
81 1
72 2
63 3
54 4
45 5
36 6
27 7
18 8
F - Coasting deceleration
Suggested code nos.
Characteristic of separation
ACCEL DECEL
Density gradient centrifugation 
using a vertical rotor
5 7 The sample and gradient in tubes reorient during accel-
eration and deceleration. Therefore, the sample and 
gradient can become mixed, especially in wide tubes, if 
you use rapid acceleration or deceleration.
DNA separation by CsCl iso-
pycnic separation (self-forming 
gradients)
9 7 You can operate at maximum acceleration because the 
density gradient is not formed during the run. As for the 
deceleration, it is better to decelerate slowly to obtain 
sharp bands.
Pelleting using a fixed angle 
rotor
9 9 Rapid pelleting of samples is possible (the run time 
decreases).
Density gradient centrifugation 
using a swinging bucket rotor
8 8 The sample and gradient do not reorient. Therefore, 
mixing of the layers is less than that in the case of using 
a vertical rotor.
Note For a swinging bucket, there is no difference with regard to turbulence if ACCEL/DECEL is 
less than or equal to 8. However, when the mode for long acceleration time is selected, (1, 2, 3), an 
imbalance alarm indicator may light.










