Electrical Connections
71 Liebert
®
CRV
™
9.2.1 Power Supply Cable Connections
• Connect the cable to the line inlet terminal board.
• Use the appropriate cable size for the current draw, supply voltage and installation type.
• Protect the supply using a backup fuse or circuit breaker.
• Do not fit the supply cable in the raceways inside the unit’s electric board—600mm (24") units.
• Use only multipolar cables with sheath (CEI20-22).
Wiring Connections
• Remote On/Off connections must be provided by the installer.
• The General Alarm terminals allow remote alarm signalling.
In case of short circuit, check the affected switch for sticking and replace it if necessary.
See electrical data in Table 38.
9.3 Protective Features of the Electronically Commutated Fans—All Models
The EC fans are protected against:
• Overtemperature of electronics
• Overtemperature of motor
• Locked rotor protection
• Short circuit at the motor output
When any of these failures occurs, the motor stops, electronically, with no potential for separation,
and the status relay is released.
The unit does not restart automatic automatically. To reset the alarm, the power supply must be
switched Off for 20 minutes once motor is at standstill.
• Input power undervoltage detection:
If the utility power falls below 3ph/290VAC (typical value) for 5 seconds or longer, the motor is
switched Off, electronically, with no potential for separation, and the status relay is released.
When the utility voltage returns to a correct value, the motor restarts automatically.
• Phase failure recognition:
If one phase fails for 5 seconds or longer, the motor is switched Off, electronically, with no
potential for separation, and the status relay is released.
When all three phases return to correct values, the motor restarts automatically in 10 to 40
seconds.
The power supply for an external speed-setting potentiometer is protected against short-circuiting.
The motor is overload-protected via motor current limitation.
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