User manual

Electrical Connections
Liebert
®
DS
™
76
8.0 ELECTRICAL CONNECTIONS
Three-phase electrical service is required for all models. Electrical service must conform to national
and local electrical codes. Refer to equipment nameplate regarding wire size and circuit protection
requirements. Refer to electrical schematic when making connections. Refer to Figure 61 for
electrical service entrances into unit.
A manual electrical disconnect switch should be installed in accordance with local codes and
distribution system. Consult local codes for external disconnect requirements.
NOTICE
Risk of improper electrical connection of three-phase input power. Can cause unit damage.
Service technicians should use a gauge set on the Liebert DS system during the initial startup
to verify that the three-phase power is connected properly. The EC fans are not a reliable
indicator of proper connection. The blowers will rotate the same direction, regardless of the
three-phase power input.
NOTICE
Risk of backward compressor rotation. Can cause equipment damage.
Three-phase power must be connected to the unit line voltage terminals in the proper
sequence so that scroll compressors rotate in the proper direction.
NOTICE
Risk of improper electrical supply connection. Can cause equipment damage.
See transformer label for primary tap connections. Installer will need to change transformer
primary taps if applied unit voltage is other than pre-wired tap voltage.
NOTICE
Risk of overheated terminals. Can cause wiring and component damage.
Use copper wiring only. Make sure that all connections are tight.
!
WARNING
Risk of electric shock. Can cause injury or death.
Disconnect local and remote power supplies before working within.
Use voltmeter to make sure power is turned off before making any electrical connections.
Before proceeding with installation, read all instructions, verify that all the parts are included
and check the nameplate to be sure the voltage matches available utility power.
50Hz Models Only: Re-install all terminal covers before connecting power to the unit.
Failure to install these covers exposes high-voltage terminals.
Follow all local codes.
!
WARNING
Risk of improper wiring, piping, moving, lifting and handling. Can cause equipment damage,
injury or death.
Installation and service of this equipment should be done only by qualified personnel who
have been specially trained in the installation of air conditioning equipment.
NOTE
Seal openings around piping and electrical connection to prevent air leakage. Failure to do so
could reduce the unit’s cooling performance.