Wiring Diagrams; Direction Of Rotation; Protection From Electro-Chemical Corrosion; Frequency Converter Operation - Grundfos SRP Instrucciones De Instalación Y Funcionamiento

7.5 Wiring diagrams

U1 V1 W1 W2 U2 V2
Fig. 16 Three thermal switches (PTO, bimetallics)
Terminals Description
Ends of the three stator windings
1, 2, 3, 4, 5, 6
(U1, U2, V1, V2, W1, W2)
11, 12 Thermal switches (F6)
21, 22 Leak sensor in gearbox (B)
U1 V1 W1 W2 U2 V2
Fig. 17 Three PTC sensors
Terminals Description
Ends of the three stator windings
1, 2, 3, 4, 5, 6
(U1, U2, V1, V2, W1, W2)
PTC sensors (according to DIN 44 081)
31, 32
(1, 2, 3)
21, 22 Leak sensor in gearbox (B)

7.6 Direction of rotation

When the electrical connections have been carried out,
check that the propeller is rotating in the correct direction.
When viewed from the motor, the propeller should rotate
clockwise.
An arrow on the motor housing shows the correct direction of
rotation.
If the propeller rotates in the wrong direction, interchange two
phases of the mains supply (L1, L2, L3).
PTO LS PE
B
PTC LS PE

7.7 Protection from electro-chemical corrosion

Two different metals or alloys cause electro-chemical corrosion if
they are connected by an electrolyte. This applies if more than
one pump is installed in the same tank. We recommend the
following additional protection:
• galvanic separation of the earth conductor from the neutral
conductor or
• galvanic separation of the mains supply by means of an
isolation transformer.
The earth conductor must be separated in such a way as to
ensure that no direct current can flow through it. It must still
function as a protective conductor. This can be achieved with a
limiting unit (polarization cell or anti-parallel diode) or an isolation
transformer.
2
3
Fig. 18 Protection from electro-chemical corrosion
Pos. Designation
1 Limiting unit
2 Earth conductor
3 Isolation transformer
Warning
When using an isolation transformer, the ratio
between starting current and rated current (I
must not be altered.

7.8 Frequency converter operation

The SRP pumps are designed for frequency converter operation
in the 40 to 60 Hz range. However the SRP pumps can run down
to 10 Hz in min frequency, having sufficient cooling in mind.
L1
L2
L3
N
PE
1
2
/I )
A N
13