Active magnetic bearings (AMBs) have been used in the industry for more than 30 years. Various industrial applications are using high-speed electrical machines in their processes. With high rotational speeds (>10 000 rpm), these machines are often subject to failures and breakdowns. These failures are compromising the productivity and efficiency of the systems they drive. High-speed electrical machines are greatly benefiting of using active magnetic bearings. They not only support the load of the rotating shaft assembly, but they also eliminate the friction usually generated between the moving and stationary parts. The benefits of active magnetic bearings are due to the frictionless operation, which improves energy efficiency, allows maintenance-free and completely oil-free operation.

Industrial applications

For several decades there were limitations, which prevented active magnetic bearings to be used by the majority of original equipment manufacturers (OEMs). SpinDrive provides easy integration of the magnetic bearing solution, which can be utilized across the industries. Our tailored active magnetic bearings’ operational principle is described here.

Figure 1  Example of SpinDrive active magnetic bearings

SpinDrive active magnetic bearings are aimed at the industrial processes. They enable high rotational speed that improves the overall process efficiency. Additionally, they provide reliable and maintenance-free operation for applications where those features have the highest priority.

Turbo compressors

An application benefitting greatly from active magnetic bearings is turbocompressors. They are used for injection and compression of gases. They are widely used in industrial processes such as chemical, food-processing, wastewater treatment, heating, ventilation and air-conditioning applications. Bearings play a critical role in turbocompressors. The use of SpinDrive active magnetic bearings allows the turbocompressors to operate without the use of any oil for lubrication. It eliminates the risk of end-product contamination. It also eliminates the need for oil-related maintenance i.e. changing oil, replacing oil-filters, separating and disposing of waste-oil, resulting in significant operational savings. Additionally, with our active magnetic bearings, turbocompressors can be protected from damage during a surge. This extends compressor operational flexibility. They can actively detect surge forces and inject current to keep the shaft rotating without breakdowns.

Turbo blowers

Turbo blowers are used in a variety of industrial processes. Turbo blowers are low-pressure turbocompressors having usually only one impeller whereas medium-pressure compressors require at least two compressing stages. The industrial processes using turbo blowers include processes related to aeration, drying, air agitation & pneumatic conveying. They are widely used in industries, such as wastewater treatment, chemical, pharmaceutical, pulp and paper, agriculture, food and beverage, aerospace, automotive, and construction. Turbo blowers work at high rotational speeds (i.e. normally operating at the range of 10 000 – 60 000 rpm). The key to promoting high efficiency involves limiting friction during this rotation. In addition, the fact that turbo blowers typically operate in harsh environments also contributes to wear. Active magnetic bearings reduce greatly both friction and wear decreasing the need for expensive repairs and equipment downtime. For instance, typically aeration blowers represent up to 80% of the annual operating expenses at water and wastewater treatment plants.

Organic Rankine Cycle

Organic Rankine Cycle (ORC) power plants convert waste heat from industrial processes into electricity. The technology is used for distributed electricity generation from renewable heat sources (such as geothermal, biomass, solar) and increasing energy efficiency of industrial processes (heat recovery from industrial processes – typically known as waste-heat-to-power applications). The biggest technological challenge is to pull energy from the lukewarm waste heat. More than 60% of global waste heat is under the boiling point of water. The cooler water is, the harder it is to pull usable energy from it. The solution for this challenge is to use higher rotational speeds of the impeller. It is often achieved by using bulky low-speed motor and gearbox, at the cost of efficiency, reliability and maintenance requirements.

The ORC turbogenerator is composed of a single radial turbine connected to a generator. SpinDrive active magnetic bearings are used to keep the shaft levitated. No lubricant is needed to drive the turbogenerator. Active magnetic bearings also enable frictionless operation eliminating energy and mechanical losses, wear and reduces maintenance associated with other bearing types. This reduces the risk of the refrigerants being contaminated by lubricant while increasing the thermal stability of the organic fluid. The active magnetic bearings withstand hazardous media that makes it the ultimate solution for any ORC system.

Other applications

More applications where active magnetic bearings would bring an added value are shown in Figure 2. The reasons for using active magnetic bearings vary from application to application. However, the core benefits of SpinDrive solution are available across the applications. We, at SpinDrive, are changing the way how active magnetic bearings are perceived by the industry and making it fast and easy to integrate and available to any OEM size. Our mission is to democratize levitation technology.

 

Figure 2  Application examples of active magnetic bearings