6
W
2
U
2
V
2
U
1
V
1
W
1
L
1
L
2
L
3
W
1
V
2
L
1
V
1
U
2
U
1
L
2
W
2
L
3
W
1
V
2
L
1
V
1
U
2
U
1
L
2
W
2
L
3
Fig. 7a.
- connection
Fig. 7b.
Y –
connection
Fig. 7c.
Y /
- start
Type of switch
Motor Power
P
N
4 kW
Motor Power
P
N
> 4 kW
power supply
3 ~ 400 V
power supply
3 ~ 400 V
direct
Y – connection (7b)
– connection(7a)
Y /
- start
Impossible
Remove connecting
bridges (7c)
Table 1
ATTENTION
Motor Power
Y - set time
30 kW
> 30 kW
< 3 sec
> 5 sec
Table 2
C5.6- Electrical connections
The electrical motors have to be built in accordance with EN 60034-1.
Enclosures of electrical motors and control systems on the pump unit shall as a minimum
give protection in accordance with EN 60529 IP22. But in determining the degree of protection of
enclosures of electrical motors and control systems on the pump unit the operating and environmental
conditions must be taken into consideration.
Electrical connection should be done by a qualified electrician. Current national regulation and motor
manufacturer’s instructions must be observed.
Take all safety precautions listed in
“Safety instructions”.
Disconnect all power supplies prior to doing any
work.
The supply cable must be laid in such a way that it never touches the pipework, pump and motor casing.
Check voltage, phase and frequency on motor nameplate with the mains.
The electric motor must be protected against overloading by means of circuit breakers and/or fuses. Circuit
breakers and fuses must be selected in accordance with full load amperage of the motor appearing on the
motor rating plate.
It is recommended to use PTC (passive thermal control) on motor, but this is optional depending on customer
requirement. In case of using PTC, these should be connected via corresponding terminals in the terminal box
and the PTC should be connected to the thermal trip mechanism.
Prior to connecting the electrical wiring rotate the pump shaft by hand to make sure rotor rotates easily.
Connect the electrical wiring in accordance with local electrical codes and make sure to ground the motor.
The connection diagram can be found in the terminal box of the motor or in the instruction manual.
The mains connection on the tagboard depends on the nominal power of the motor, the power supply and
the type of connection. The necessary connection of the bridges in the terminal box is shown in the following
(Table 1. and Fig. 7a, 7b, 7c).
In the case of three-phase induction motors with Y –
– connection it must be ensured that
the change-over points between star and delta follow on from one another very quickly.
Longer change-over
times may result in pump damage (Table 2).
