Variable Speed Drive; Vsd Power Supply-Field-Adjustment May Be Required; Wye-Connected Power Supply; Figure 62 Wye-Connected Power Diagram - Emerson Liebert DS Series User Manual

8.1

Variable Speed Drive

WARNING
!
Risk of electric shock from leakage current. Can cause injury or death.
Reconnect earth ground if servicing or replacing the variable speed drive (VSD).
An optional Variable Speed Drive (VSD) is available on some Liebert DS models. The VSD reduces
power consumption by reducing the blower speed to match the unit's load.
This packaged unit is factory-set and should not require field-adjustment.
WARNING
!
Risk of contact with nearby high speed moving parts. Can cause injury or death.
Do not attempt to adjust or view variable frequency drive settings at the display on the face of
the VSD. Instead, use a remote display (Liebert service item part number 196632P1) and
connect to the VSD remote cable in the extra low voltage electric panel.
NOTICE
Risk of improper program adjustment. Can cause equipment damage and loss of warranty.
The VSD is factory-programmed for proper operation. Altering the VSD program without
authorization from the factory may void the warranty.
NOTE
Emerson requires the Liebert DS to have a grounded supply. The VSD may be damaged if it is
operated on an ungrounded supply.
8.1.1 VSD Power Supply—Field-Adjustment May Be Required
The installer/startup technician must determine the type of three-phase supply power
(Wye-connected or Delta-connected) being used at the building power distribution panel for the
VSD-controlled unit.
NOTICE
Risk of mismatched input power supply and VSD requirements. May cause equipment
damage and failure.
The EMC filter must be removed from the VSD if the power supply is Delta-connected.
8.1.2

Wye-Connected Power Supply

No control changes are required if the Liebert VSD Control unit will be operated with Wye-connected
power.

Figure 62 Wye-connected power diagram

Winding A
Winding C
Phase A
Phase B
Winding B
Neutral
DPN001944
Phase C
Rev. 0
79
Electrical Connections