High-Performance & High-Capacity Centrifuges Catalog

www.beckmancoultercentrifugation.com

Reference

Useful Formulas

k Factor

To determine k factor

2.53 × 10 5 ln ( r max

10 -13 3600

ln ( r max

/ r min

)

/ r min

)

×

k =

OR k =

ω 2

(RPM/1000) 2

To determine pelleting time (t)

t = where s = sedimentation coefficient in Svedbergs k s

To relate pelleting time between rotors

k

k

=

1

2

t

t

1

2

To adjust k factor for runs less than maximum rotor speed

maximum rated speed of rotor actual run speed ( ) 2

3

k

= k

adj

To relate relative centrifugal force (RCF) to speed (RPM):

( ) 2 RPM 1000

RCF

RCF

= 1.12 r

OR RPM = 10 3

max

max

1.12 r

max

To relate the sedimentation coefficient (s) to rotational speed:

1 ω 2 r

× dr dt

s =

Svedberg unit ( S ) equivalent:

S = 10 -13 seconds

Reduced run speed for dense solutions:

A B

reduced run speed = max rated speed of rotor ×

where A = max. permissible density of rotor tube contents, and B = actual density of the tubes to be centrifuged

Beckman Coulter High Performance Centrifuges

3-4