How to Differentiate & Convert RCF to RPM in Centrifuges?


How to Differentiate & Convert RCF to RPM in Centrifuges?

Posted on the 7th of Jul 2023 by Westlab

Centrifugation is a method utilized to separate mixtures through the application of centrifugal force. By employing the principle of sedimentation, a centrifuge machine effectively divides substances based on their density under the influence of gravitational force.

When working with centrifuge machines, it is essential to understand two distinct units of measurement: Revolutions per minute (RPM) and Relative centrifugal force (RCF) or g-force. Although these units may appear similar, they possess significant differences. 

This blog explores the true nature of comparing and converting RCF to RPM, as well as their interconnectedness, providing valuable insights into their usage within centrifugation processes.

What is the Difference between (Relative Centrifugal Force) RCF to RPM (Revolutions Per Minute)? 

The main difference between Revolutions per minute (RPM) and Relative centrifugal force (RCF) lies in the physical quantities they represent and the information they convey within centrifugation processes.

  • RPM: Revolutions per minute (RPM) measures the rotational speed of a centrifuge rotor, indicating the number of complete revolutions it makes in one minute. It is a unit of angular velocity and provides information about the rotational speed of the centrifuge machine.
  • RCF: Relative centrifugal force (RCF), also known as g-force, measures the gravitational force experienced by a sample within a centrifuge. It represents the force applied to the particles within the sample, causing them to sediment or separate based on their density. It is expressed in multiples of the acceleration due to gravity (g), typically in units of gravity (x g).

The relationship of RCF to RPM is not a direct conversion, as they are independent variables. However, they are related through the equation:

RCF = (1.118 x 10^-5) x r x (RPM)^2


  • RCF is the relative centrifugal force in units of gravity (x g).
  • r is the radius of the centrifuge rotor in centimeters.
  • RPM is the revolutions per minute.

This equation demonstrates that RCF is influenced by both the radius of the rotor and the square of the RPM. Therefore, to achieve a specific RCF, adjustments in either the RPM or the rotor radius must be made.

RCF vs RPM Conversion

To derive the relative centrifugal force (RCF) or g force from revolutions per minute (RPM), a specific formula is employed: 

RCF = (RPM)2 × 1.118 × 10-5 × r 

This equation highlights the connection between RPM and RCF, where RCF depends on the square of the rotational speed in RPM and the distance (r) of the particles from the center of rotation. By expressing the speed of rotation in RPM and the distance in centimeters, one can accurately calculate the corresponding RCF value.

The Power of Controlled Forces - RCF to RPM in Centrifuges 

Centrifuge machines form the backbone of numerous laboratory Procedures, enabling the precise separation of substances based on density. By adjusting the RPM and RCF settings, researchers can tailor the forces exerted on samples, driving effective separation. The RPM value determines the rotational speed of the centrifuge rotor, while the RCF value governs the relative centrifugal force or g-force experienced by the samples.

Accelerating Discoveries with Precise RPM to RCF Calculations

High-speed centrifuges deliver the necessary power for applications demanding rapid sedimentation or pelleting. Operating at significantly higher RPM and RCF values, these robust machines swiftly separate cellular debris, subcellular fractions, and particles. Fields such as cell biology, microbiology, and immunology harness the capabilities of high-speed centrifuges to expedite research and maximize efficiency.

At the pinnacle of centrifugation technology in Lab Equipment, ultracentrifuges enter on a scientific journey into the realm of macromolecules. With RPM and RCF values that reach extraordinary heights, ultracentrifuges allow researchers to delve into the intricate world of proteins, nucleic acids, and lipids. Precise control over forces empowers delicate separations and fractionations, fueling breakthroughs in biochemistry, molecular biology, and biophysics.

Which Unit of Centrifuge is Better for Research? - RCF vs RPM

Using RCF or g-force as a parameter provides precise control and accuracy in centrifugation experiments, as it takes into account the influence of the rotor size. Unlike RPM, which only indicates the rotational speed, RCF remains constant regardless of the specific centrifuge machine being used. This means that by setting the desired RCF, researchers can ensure consistent acceleration and sedimentation forces on the samples, regardless of the rotor size of the centrifuge. Consequently, RCF proves to be a reliable and standardized measurement for conducting experiments with accuracy and reproducibility.

In summary of RPM to RCF, RPM represents the rotational speed of the centrifuge rotor, while RCF indicates the gravitational force acting on the sample. Understanding the distinction between these two parameters is crucial for proper centrifuge operation and obtaining desired separation results in various applications.

In the world of Lab Equipment, the conversion of RCF to  RPM and vice versa is crucial for maximizing the effectiveness of centrifugation. Different instruments like microcentrifuges, high-speed centrifuges, and ultracentrifuges serve specific purposes in research. They provide scientists with tools to apply precise forces and uncover new knowledge. By understanding how RCF and RPM work with Lab Supplies Online, researchers can make significant advancements in their scientific endeavors. It's a journey that leads to excellence in scientific discoveries.

2023-07-07 06:28:00
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