Connection Of Three-Phase Motors - Grundfos SP14-27 Installation And Operating Instructions Manual

6.7 Connection of three-phase motors

Three-phase motors must be protected.
See section 6.2.2 Three-phase motors.
For electrical connection via the MP 204, see the separate
installation and operating instructions for this unit.
When a conventional motor-protective circuit breaker is being
used, the electrical connection should be carried out as described
below.
6.7.1 Checking the direction of rotation
The pump must not be started until the suction
Caution
interconnector has been completely submerged
in the liquid.
When the pump has been connected to the power supply, check
the direction of rotation:
1. Start the pump and measure quantity of water and head.
2. Stop the pump and interchange two phases.
3. Start the pump and measure quantity of water and head.
4. Stop the pump.
5. Compare the two results. The connection giving the larger
quantity of water and the higher head is the correct one.
6.7.2 Grundfos motors - direct-on-line starting
The connection of Grundfos motors wound for direct-on-line
starting appears from the table below and fig. 15.
Mains
Grundfos 4" and 6" motors
PE
L1
L2
L3
Check the direction of rotation as described in section
6.7.1 Checking the direction of rotation.
PE L1
PE U
M
3
Fig. 15 Grundfos motors - direct-on-line starting
10
Cable/connection
PE (yellow/green)
U (brown)
V (black)
W (grey)
L2 L3
V W
6.7.3 Grundfos motors - star-delta starting
The connection of Grundfos motors wound for star-delta starting
appears from the table below and fig. 16.
Connection
PE
U1
V1
W1
W2
U2
V2
Check the direction of rotation as described in section
6.7.1 Checking the direction of rotation.
PE L1
W2 U2
PE U1
Fig. 16 Grundfos motors wound for star-delta starting
If direct-on-line starting is required, the motors should be
connected as shown in fig. 17.
PE L1
W2 U2
PE U1 V1
Fig. 17 Grundfos motors wound for star-delta starting -
direct-on-line starting
Grundfos 6" motors
Yellow/green
Brown
Black
Grey
Brown
Black
Grey
L2 L3
V2
V1 W1
M
3
L2 L3
V2
W1
M
3