berita perusahaan tentang Working Principle of Danfoss Turbocor Magnetic Bearings and VFD Drives

In modern industrial refrigeration systems and large HVAC chillers, traditional oil-lubricated refrigeration compressor designs face an unavoidable thermodynamic bottleneck: oil contamination inside heat exchangers. The oil film coating copper tubes acts as thermal insulation, reducing the evaporator's heat transfer efficiency.

The Danfoss Turbocor oil-free centrifugal platform completely resolves this issue by replacing mechanical contact bearings with active magnetic levitation and variable frequency drive (VFD) technology.

Active Magnetic Levitation: Realizing Frictionless Rotor Shaft Suspension

The core of the Turbocor compressor is its Active Magnetic Bearing (AMB) system. Instead of being supported by journal or roller bearings, the forged aluminum-alloy shaft floats in a magnetic field generated by radial and axial electromagnets.

Real-Time Position Sensing

Position sensors track the shaft's position at a sampling frequency of 10,000 Hz. Any orbital deviation as small as 1 μm triggers an immediate adjustment to the current in the electromagnetic coils.

Zero Mechanical Contact

During operation, the shaft levitates within a continuous dynamic gap. Since there is no physical contact between rotating and stationary components, mechanical friction is virtually eliminated, keeping sound levels below 70 dBA when measured at a 1-meter distance.

Variable Frequency Drives and Partial-Load Efficiency

Centrifugal compression follows the affinity laws, which means power consumption decreases cubically as shaft speed drops.

With an integrated onboard inverter, the compressor continuously adjusts motor speed between 18,000 RPM and 48,000 RPM to match real-time cooling loads. Under part-load conditions in cold storage staging or comfort cooling applications, reducing shaft speed lowers discharge head without relying on energy-intensive inlet guide vane (IGV) throttling. This delivers Integrated Part-Load Values (IPLV) exceeding 10.0 when tested in accordance with AHRI 550/590 standards.

Heat Transfer Improvements and Simplified Compressor Maintenance

Removing oil from the refrigerant circuit delivers substantial thermodynamic benefits. In conventional flooded evaporators, an oil concentration of just 1% can reduce the heat transfer coefficient by up to 15%.

Eliminating oil pumps, oil separators, heaters and filter elements streamlines routine compressor maintenance:

• No Oil Charges: Eliminates costs related to synthetic lubricant contamination and disposal.
• Consistent Peak Efficiency: The heat exchanger surface conductance remains at 100% of the design specification throughout the entire service life of the equipment.
• Soft Starting: The VFD draws a starting current of less than 2 Amps, preventing voltage sags on the facility power grid.

Ready to Upgrade to Oil-Free Centrifugal Technology?

Planning a high-efficiency chiller retrofit, or calculating the payback period for higher IPLV? Contact our technical engineering team today to request compressor performance maps, electrical wiring schematics or CAD envelope models.