The Role of Brushless Motors in Laboratory Centrifuges

Release time:

2012-09-16

Overview:

In the past, motors were DC motors equipped with carbon brushes. During operation, these carbon brushes wore down, producing sparks, noise, and even vibrations. Moreover, carbon brushes had a limited lifespan, requiring replacement before the motor could resume operation. Even more serious was the pollution caused by carbon dust generated from brush wear—this not only contaminated the centrifuge itself but also spread to the surrounding environment. Such contamination is entirely unsuitable for the healthcare industry.

The brushless motor directly drives the centrifuge by rotating the rotor at high speed. In the past, motors used were DC motors equipped with carbon brushes. During operation, these carbon brushes wore down, producing sparks, noise, and even vibrations. Moreover, carbon brushes had a limited lifespan, requiring replacement before the motor could resume operation. Even more serious is that the wear of carbon brushes generated carbon dust, which not only contaminated the centrifuge itself but also polluted the surrounding environment. Such contamination is entirely unsuitable for the healthcare industry.

When the rotor spins at high speed, air friction generates heat, causing the rotor's temperature to rise and, consequently, the temperature of the sample in the tube to increase as well. Since biological samples are highly sensitive to temperature, centrifugation experiments generally require that the temperature be maintained at 4°C. Without intelligent computer-controlled technology, it would be impossible to achieve such precise temperature control. Therefore, a refrigeration system is used to cool the centrifuge chamber, thereby cooling both the rotor and the sample. However, measuring the actual temperature of a rotating rotor is extremely challenging. Both domestically and internationally, temperature sensors are typically embedded near the bottom of the centrifuge chamber, close to the rotor, to indirectly measure the rotor's temperature. The T-compensation for blood-type centrifuges is also influenced by the rotor’s type, rotational speed, and operating time.

Brushless Motor Centrifuge Performance:

In the past, the typical manifestation of analog technology involved using knobs to select operational parameters—such as rotational speed, temperature, and time—and displaying data via pointers on dials. Today, with the advent of digital technology, the typical approach is fully computer-controlled, featuring user-friendly interfaces, keyboard operation, digital displays, and programmable functions. At the heart of this system lies intelligent control, which is realized by computers. All parameters required for centrifuge operation—such as rotational speed, temperature, duration, acceleration/deceleration rates, and others—are entered via keyboard and displayed digitally. As a result, the error in selecting operational parameters and reading values is extremely minimal. However, this approach has certain drawbacks: the accuracy of parameter selection and data reading is highly susceptible to human factors—both from the operator and the person taking readings—leading to poor control precision. Moreover, each operation requires the same repetitive steps, resulting in poor repeatability. Although some centrifuges now feature digital displays (e.g., using knobs to set values while displaying them digitally), despite improvements in readability, the underlying principle remains analog technology. Furthermore, since these centrifuges are programmable, a set of operational parameters can be assigned numerical codes for easy storage and retrieval.

Methods for vibration reduction in laboratory centrifuges

Common models of centrifuges routinely used in hospital laboratories.