Danfoss Turbocor VTT Series, Service Manual

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M-SV-VT-001-EN Rev. A
Compressor Fundamentals
Compressor operation begins with a demand signal applied to the Compressor through the CIM. The
startup sequence is configurable in the startup settings. Refer to the OEM Programming Guide for
further details.
2.1 Main Fluid Path
The VTT Compressor is a two-stage centrifugal type compressor utilizing patent-pending IntraFlow™
technology. This new technology eliminates the need for Inlet Guide Vanes or variable geometry
diffusers.
Using on-board sensors, the Compressor Control Module (CCM) can predict where the Compressor
is operating within the aero map with respect to surge power, thus commanding the IntraFlow™
Valve (IFV) to open or close to avoid surge. Refer to Figure 6 (IFV Flow) for an illustration of the
recirculation flow.
Figure 6 - IFV Flow
2.2 Economizer
The VTT Compressors are designed with an economizer input option. The following are two (2) types
of economizer arrangements that can be used:
• Sub-cooler (closed)
• Flash tank (open)
For further details, refer to the VTT Applications Manual.
Recirculation
Flow
2.3 Compressor Cooling
Figure 7 - Motor Cooling
Path
To the vapor side of the evaporator
Electronnic Expansion Valve
Subcooled
Liquid
Superheated
Vapor
Refer to Figure 7 (Motor Cooling Path) for the illustration of the internal cooling path.