Title: Full Interpretation of Real-World Applications And Measured Data of The Magnetic Bearing / High-Speed Motor Rotor in Centrifugal Blowers

Introduction

In industrial production, blowers are major energy consumers in industries such as wastewater treatment, chemical, cement, and paper. Taking wastewater treatment as an example, blower energy consumption accounts for 50%–60% of the total operating costs of a treatment plant. For many years, the mainstream equipment used in the industry has been Roots blowers and traditional centrifugal blowers. However, these devices have inherent problems such as long drive chains, high mechanical friction, and high operating noise, leaving very limited room for further energy efficiency improvements.

Is there a technology that can make the blower rotor "float", completely eliminating mechanical friction? This is precisely the answer provided by magnetic bearing / high-speed motor technology. This article focuses on the core technology of the magnetic bearing / high-speed motor rotor, combined with real-world application cases and measured data, to comprehensively analyze its performance in centrifugal blowers.

I. Technological Innovation: Making the Rotor "Float"

The core design concept of a magnetic bearing centrifugal blower can be summarized in one sentence: Using electromagnetic force to replace mechanical bearings, allowing the rotor to spin while suspended in the air.

1.1 Core Structure

A magnetic bearing centrifugal blower consists of four major core components: a high-efficiency centrifugal impeller, a high-speed permanent magnet synchronous motor, an active magnetic bearing system, and a dedicated frequency converter. The key innovation lies in the integrated design of the magnetic bearings and the high-speed motor.

Traditional blowers mostly use a multi-stage transmission structure of "motor + belt/gear speed increase + impeller". This involves multiple mechanical contact points, each representing an energy loss. In contrast, the magnetic bearing centrifugal blower directly mounts the blower impeller onto the extended end of the motor shaft, with the rotor vertically suspended on active magnetic bearing controllers. No speed increaser or coupling is needed; the high-speed motor directly drives the impeller.

1.2 Five-Degree-of-Freedom Active Magnetic Bearing Technology

Current mainstream products use five-degree-of-freedom active magnetic bearing technology. The system uses built-in displacement sensors to detect the rotor's positional changes in each direction in real time. The signals are sent to a controller for computation and amplification, which outputs control current to adjust the electromagnetic force magnitude, thereby precisely stabilizing the rotor at the set position. A typical control refresh frequency can reach 10,000 times per second, enabling dynamic and precise correction of the rotor position.

Since there is no physical contact between the rotor and the bearings, three major technical advantages are achieved: "zero friction, zero oil contamination, zero wear". This means:

• No lubricating oil required – the delivered air is absolutely clean, eliminating secondary pollution.

• No mechanical wear – equipment service life is greatly extended.

• Maintenance is greatly simplified – only requires periodic replacement of filter media.

1.3 High-Speed Permanent Magnet Synchronous Motor – The Rotor's Power Core

The stable suspension of the rotor is only the prerequisite; it also needs powerful drive to spin the impeller at high speed. The magnetic bearing centrifugal blower uses a high-speed permanent magnet synchronous motor (PMSM) , whose rotor features surface-mounted permanent magnets wrapped and protected by a carbon fiber sleeve.

Why use a carbon fiber sleeve? The reason is simple: the rotor spins at speeds exceeding 20,000 rpm, subjecting the permanent magnets to enormous centrifugal force. Without a high-strength sleeve restraint, the rotor would easily disintegrate. Carbon fiber material has low density and extremely high strength, making it ideal for this demanding application. The paired rare-earth permanent magnets provide high magnetic field energy, ensuring the motor maintains high efficiency at high speeds.

Currently, the efficiency of such high-speed PMSMs can reach 96% or even over 97% , far superior to traditional induction motors.

II. Real-World Application Scenarios

2.1 Wastewater Treatment: The Main Battlefield for Energy Saving and Consumption Reduction

Wastewater treatment is the largest application area for magnetic bearing centrifugal blowers because the biological aerobic stage of treatment requires continuous heavy aeration, with blowers running 24/7 all year round.

At the Tianjin TEDA New Water Source West Wastewater Treatment Plant, old Roots blowers were replaced with high-efficiency energy-saving magnetic bearing centrifugal blowers from Yisheng Technology. Measured data showed that after the retrofit, the energy saving rate reached 26.5%, and noise dropped below 85 dB.

An even more representative case comes from a semi-underground wastewater treatment plant in Shaanxi Province. The plant treats 20,000 tons of wastewater per day, using three YG75 and three YG100 Yisheng magnetic bearing blowers deeply integrated into the entire wastewater treatment process. Through precise aeration control, the plant achieved sludge moisture content below 60%, zero wastewater discharge, and 100% reclaimed water reuse. The project uses the "Feixuan Cloud" IoT monitoring platform, collecting key operating parameters such as vibration, temperature, and current in real time, reducing inspection workload by 50%.

2.2 Chemical Industry: Demanding Continuous Operation Conditions

Air supply requirements in the chemical industry are often more stringent – not only high flow rate and high pressure, but also very high demands on continuous operation reliability.

For example, at the carbon black workshop of a tire factory in Shandong Province, the original combustion air blower was a 900 kW multi-stage centrifugal fan. After replacing it with a Yisheng YG700 magnetic bearing blower, the fan delivers a precise output of 400 m³/min at 100 kPa pressure, matched with a 10 kV high-voltage power distribution system for continuous operation. While fully meeting process requirements, the operating power dropped to 700 kW.

In another chemical company's wastewater aeration retrofit project, a single magnetic bearing blower achieved a power saving rate of 38.2% under the same operating conditions, saving 975,000 kWh annually and reducing CO₂ emissions by 556.9 tons. Between 2021 and 2024, another chemical company successively installed four magnetic bearing blowers for desulfurization oxidation processes, achieving an average annual total power saving of 1.67 million kWh and cost savings of 1.203 million RMB, with an average power saving rate exceeding 30%.

2.3 Cement Industry: Stable Performance in High-Dust Environments

Cement plants have high dust levels and large operating fluctuations, posing a severe test for blowers. After a cement plant in Shandong Province introduced a magnetic bearing centrifugal blower in a retrofit, it achieved 16.67% energy savings despite a 17% increase in airflow, saving nearly 259,200 kWh annually, with a noticeable reduction in on-site noise.

III. Compiled Measured Data: How Much Does a Magnetic Bearing Blower Actually Save?

To visually demonstrate the actual performance of magnetic bearing centrifugal blowers, we have compiled measured data from various industries.

Table: Measured Data from Magnetic Bearing Centrifugal Blower Applications Across Industries

This summary table reveals a clear pattern: Magnetic bearing centrifugal blowers generally achieve 20%–30% or higher energy savings across different industries and operating conditions, with individual optimized cases exceeding 38%.

It is worth noting that energy savings are only part of the benefit. Magnetic bearing equipment also brings substantial maintenance cost reductions. For example, in the tire factory carbon black workshop, maintenance costs dropped by 80%, requiring only periodic filter changes. The design life is also significantly extended – traditional Roots blowers typically require major overhaul every 1-2 years, while magnetic bearing blowers can have a design life of up to 20 years.

IV. In-Depth Analysis of Measured Data

4.1 Deconstructing the Energy Saving Effect: Efficiency Gains from Multiple Aspects

The energy saving effect of magnetic bearing centrifugal blowers does not come from a single factor but from the accumulation of multiple technologies:

(1) Direct-drive structure eliminates transmission losses. Traditional Roots blowers rely on gears or belt drives, each step of mechanical transmission incurring 3%-5% energy loss. Magnetic bearing blowers use direct drive from motor to impeller, achieving near 100% power transmission efficiency – saving approximately 12% compared to traditional gear-driven single-stage centrifugal blowers.

(2) Motor efficiency is greatly improved. High-speed PMSMs can achieve 96%-97% efficiency, while traditional motors often fall below 90% efficiency at partial loads. The motor itself thus "extracts" about 7-10 percentage points of efficiency gain. For example, equipment from Nanjing CIGU Technology maintains stable system efficiency in the rated speed range of 18,000-40,000 rpm and power range of 40-150 kW.

(3) Magnetic bearings consume very little power. The power consumption of active magnetic bearings is typically below 1 kW, while a comparable mechanical bearing plus oil lubrication system often consumes several times that. Experimental data from CRRC Yongji Electric shows that its magnetic bearings operate stably at 22,000 rpm, with bearing power consumption kept at a very low level.

(4) Aerodynamic optimization of the three-dimensional flow impeller. The high-speed centrifugal impeller uses a three-dimensional (3D) flow design theory. After parametric optimization, the impeller can achieve up to 85% efficiency at its operating point, with a much wider high-efficiency operating range than traditional impellers. This design maintains high efficiency under varying airflow conditions, making it especially suitable for applications with fluctuating loads like wastewater treatment. CRRC's products use such 3D flow high-efficiency impellers to achieve wide-range high-efficiency operation.

The combination of these factors increases the overall system efficiency by over 85% compared to traditional fans, with a comprehensive energy saving rate stable in the 20%-30% range.

4.2 Operational Stability Data

For industrial equipment, whether energy savings are "stable" is equally critical. Here are key indicators reflecting reliability:

• Vibration control: The vibration level of magnetic bearings is an order of magnitude smaller than that of traditional bearings. Under normal operation, vibration severity can be controlled within 0.5 mm/s. The system uses self-balancing technology and active vibration reduction design, resulting in extremely low body vibration.

• Intelligent monitoring: The equipment is equipped with an intelligent control system that monitors dozens of parameters in real time, including airflow, pressure, bearing temperature, winding temperature, and rotor orbit. It supports multiple operating modes (constant flow, constant speed, constant pressure) and multiple control methods (local, central control, wireless).

•  Surge prevention: Magnetic bearing blowers are equipped with surge prediction and anti-surge functions. Under unstable conditions such as excessively low inlet pressure or sudden speed drop, the system automatically adjusts, effectively protecting equipment safety. When anomalies are detected, the system automatically warns and adjusts speed and airflow to avoid entering the surge region.

• Power failure protection: The equipment is equipped with auxiliary bearings and a self-powered power failure backup system. In the event of an unexpected power outage, it can still keep the rotor suspended, preventing bearing damage due to speed decay.

V. Future Outlook

The breakthrough in magnetic bearing / high-speed motor rotor technology has moved centrifugal blowers from the "mechanical transmission era" into the "electromagnetic direct-drive era". According to industry data, the global industrial magnetic bearing blower market revenue was approximately 

1.292 billion by 2032, with a compound annual growth rate (CAGR) of about 16.2%. The Chinese market is also showing strong growth. Magnetic bearing centrifugal blowers have already achieved large-scale application in several high-energy-consuming sectors and have been included in the "National Industrial and Information Technology Field Energy Saving and Carbon Reduction Technology and Equipment Recommendation Catalog (2025 Edition)".

Domestic enterprises such as CRRC Yongji Electric have made breakthroughs in key technologies including high-speed magnetic bearing rotor design, carbon fiber sleeve application, and active magnetic bearing integration. Their products can achieve speeds up to 22,000 rpm with motor efficiency exceeding 96%. Companies such as Yisheng Technology, Tianrui Heavy Industry, and Nanjing CIGU Technology are also continuously promoting the engineering deployment of magnetic bearing blowers in their respective fields.

As the "dual carbon" strategy advances, magnetic bearing / high-speed motor technology is expected to expand from its traditional strongholds in wastewater treatment, chemical, and cement into broader industrial scenarios such as flue gas desulfurization, biological fermentation, and mineral flotation, becoming an important force for industrial energy saving and carbon reduction.

Conclusion

The application of the magnetic bearing / high-speed motor rotor in centrifugal blowers has proven its value with a series of measured data – 20%-38% energy savings, 80% reduction in maintenance costs, design life of up to 20 years, and noise levels below 80 dB. Behind these numbers lies the successful realization of the "zero friction, zero oil, zero wear" technical concept.

For industrial enterprises seeking equipment upgrades and energy-saving retrofits, the magnetic bearing centrifugal blower is not just a more power-efficient machine; it is a system solution that reduces total lifecycle operating costs. In today's era of rising energy costs, its payback period is becoming increasingly shorter – from 3.4 years in the Ningbo Wanhua project to 1.9 years in the Ningbo Mitsubishi Chemical project. Based on real-world cases, the economics are well worth calculating.