Liebert Air Cooled - Manual (Page 25)

Inspection and Installation
21
3.7.1 VFD Control Condensers (TCDV) only
The installer/startup technician must determine the type of 3-phase supply power being used for the
VFD Control Condenser: Wye-connected power or Delta- connected power.
Wye-connected power has two different voltages that can be measured: Phase-to-Phase voltage (this
is equal to the nominal input voltage) and Phase-to-Neutral voltage (typically used for small single
phase loads (120 VAC or 277 VAC). See Figure 16.
Delta-connected power only has one voltage level that can be measured: Phase-to-Phase. See
Figure 17.
3.7.2 Wye-Connected Power Supply
No control changes are required if the Liebert VFD Control Condenser will be operated with Wye-con-
nected power.
Figure 16 Wye-connected power diagram
3.7.3 Delta-Connected Power Supply
Figure 17 Delta-connected power diagram
Phase A
Phase B
Phase C
Neutral
Winding
A
Winding
B
Winding
C
Winding
A-B
Winding
C-A
Winding B-C
Phase A
Phase B
Phase C