Sigma 4-15C - Page 84

Operating Manual SIGMA 4-15C, page 84 of 95
03/06
9.3 Entry Limitations
Valid entries or area limits could depend on:
− Type of centrifuge
− Rotor
− Interdependent parameters
All entry limits are automatically checked. When reaching a limit the operation is
stopped.
Interdependent parameters are limited further with a change of the corresponding
parameter. With the alteration of a parameter, the corresponding parameter is
recalculated. If the changed parameter is selected, the recalculated value is
displayed.
9.4 Mathematical Relations
9.4.1 Relative Centrifugal Force (RCF)
The parameters speed, RCF and the diameter of the rotor are interrelated via the
following formula:
RCF = 11,18 x 10
-6
x r x n
2
If two values are given, the third value is determined by the equation. If the speed
or the rotation radius is changed, the resulting RCF will be recalculated. If the
RCF is altered, the speed under consideration of the radius is adapted
accordingly.
r = radius in cm
n = speed in rpm
RCF without dimension
9.4.2 Density
If the density of the liquid is higher than 1.2 g/cm
3
, the allowed maximum speed
of the centrifuge is calculated according to the following formula:
n = n
max
x )/2,1( Rho
Rho = density in g/cm
3