mcr OMEGA pro
Power and Control Panel
„MERCOR” S.A. –
The company reserves the right to modify and amend this document without notice.
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3.7.2.
FAN STARTING CONTACTOR SYSTEMS
W centralach mcr OMEGA pro do rozruchu wentylatorów i silników stosowane są klasyczne metody
stycznikowe:
DOL (Direct On Line): The interfaced motor (e.g. of a fan) is connected directly to the mains by
switching the contactor coil, switching over the contactor contacts, and feeding the rated voltage to the
motor input terminals. This solution is commonplace for motors up to 5.5 kW. The starting current may
grow up to 8× In (the motor current rating).
Star/delta (Y/
Δ) connection: High-power motors are usually started with a Y/Δ connection system that
can largely reduce the starting current value (down to 3× In), resulting with lower conductor sizes.
During the starting initial phase, the motor winding is connected in a star configuration; an automatic
switching control changes the connection to delta when the rotor reaches its nominal rpm. This reduces
the current draw. This solution is commonplace for motors above 5.5 kW.
Dahlander connection (two-speed): This contactor arrangement permits automatic control over the
motor rpm speed by changing the pole pair number (Y/YY).
Independent winding (two-speed): This contactor arrangements provides rpm speed control for the
motors with double independent windings e.g. double star.
Reversing connections: this contactor arrangement enables reversing the rotation direction of a fan by
swapping the order of phases in all of above starting connection solutions, including the two-speed
varieties.
The contactor starting systems feature acknowledgement of electric drive power connection and contactor
switchover to confirm that the interfaced fans run properly. It is also possible to monitor the fan power
supply line continuity. The table below show the connections between the Power and Control Panel and
the motors.
Starting
Direct On Line
Star/Delta
Dahlander
Independent windings
Motor
wiring
diagram
Live
conductors
4x (*)mm
2
7x (*)mm
2
7x (*)mm
2
Motor
Winding
terminals
The motor winding
terminals are
connected (Y/
Δ)
according to the
supply voltage
rating and the
motor name plate.
Separate lead-out to each
motor winding terminal.
Separate lead-out to each motor
winding terminal.
(*) The conductor size should be selected according to the motor rated power. The suggested number of lines per motor is proviced for drives
without service switch monitoring.
Fan
Fan
Fan
