Danfoss Turbocor TT Series, Service Manual

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Figure 2-5 Compressor Cooling Path - TTS300/TGS230
Table 2-3 Compressor Cooling Path - (TTS300/TGS230)
No. Description No. Description
1 From Motor Winding Temp Sensor 8 SCR Manifold
2 BMCC 9 Motor/Rotor Cooling Gas
3 Solenoid M 10 *MT Only Cooling path re-enters at the suction line of the chiller
4 Solenoid E 11 *MT Only Pressure Regulating Valve
5 Liquid Refrigerant Inlet 12 *MT Only Cooling path redirects outside of the compressor
6 Orifice 13 From Motor Cavity Temp. Sensor
7 From Inverter Temp Sensor 14 Inverter
2.3 Capacity Control
Capacity control of the compressor is achieved primarily by speed modulation. When unloading, the compressor’s
first action is to reduce speed to slightly above the minimum (surge) speed for the pressure ratio present at the time.
Further reduction in capacity and an increase in shaft/impeller stability can be achieved by closing the IGVs. These
are variable angle vanes installed in the suction inlet ahead of the first-stage impeller. These guide vanes restrict the
refrigerant from entering the impeller inlet, as well as imparting a “pre-swirl” of the refrigerant in the direction of
impeller rotation to increase energy efficiency during part load operation.
M-SV-001-EN Rev. H-1/23/2023 Page 37 of 294