User manual

Maintenance
137 Liebert
®
DS
™
13.2.4 Electronic Variable Speed Drive - Inverter
On Liebert DS models with digital scroll, an optional, variable speed drive is available. This packaged
unit is factory-set and should not require field adjustment.
Removing VSD from Liebert DS
1. Turn off power at the unit disconnect.
2. Remove the front right panel.
3. Remove the VSD subassembly from the unit shoulder (downflow) or from the unit floor (upflow).
To find the inverter in downflow units, see Figure 1; refer to Figure 2 for the inverter’s location
in upflow units.
4. Remove the VSD sheet metal cover from the VSD subassembly.
5. Label the wires from the VSD, then disconnect the wires from the VSD junction box.
6. Remove the VSD from the sheet metal bracket.
7. Install the new VSD on the sheet metal bracket.
8. Reconnect wires to the VSD.
9. Reinstall the VSD sheet metal cover.
10. Re-mount the VSD on the unit shoulder or on the unit floor.
11. Reinstall the right panel.
12. Engage power to the unit disconnect.
13.3 Blower Drive System—EC Fans
13.3.1 Fan Impellers and Bearings
Fan impellers should be periodically inspected and any debris removed. Check to ensure that the
impellers can rotate freely and that the fan guards are still properly mounted for sufficient protection
against accidentally contacting the impeller. Bearings used on the units are maintenance-free. Con-
sult the factory for more information.
13.3.2 Protective Features
Monitoring functions protect the motor against overtemperature of electronics, overtemperature of
motor and incorrect rotor position detection. With any of these failures, an alarm will display through
the Liebert iCOM and the motor stops electronically. There is no automatic restart. The power must
be switched off for a minimum of 20 seconds once the motor is at a standstill.
The motor also provides locked rotor protection, undervoltage/phase failure detection and motor cur-
rent limitation. These conditions will display an alarm through the Liebert iCOM.
!
WARNING
Risk of electric shock. Can cause injury or death.
Disconnect all local and remote electrical power supplies before working within the unit.
When connecting the motor to input power, dangerous voltages occur. Do not open the motor
within the first 5 minutes after disconnection of all phases.
!
WARNING
Risk of electric shock. Can cause injury or death.
Dangerous external voltages can be present at main fan terminal KL2 even after the motor
has been turned off.
!
WARNING
Risk of improper handling. Can cause injury.
Use proper skin protection when touching the electronics housing or allow time for the
housing to cool before replacing parts.
The electronics housing can get hot and can cause severe burns