Protection From Electro-Chemical Corrosion; Start-Up - Grundfos SRP Installation And Operating Instructions Manual

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. 19 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.

8. Start-up

Check the oil level in the gearbox before starting up the pump.
The oil level must cover between 50 and 75 % of the gearbox.
If required, fill oil into the gearbox through the oil filling hole
(pos. 2). For oil quality and quantity, see section 9.3 Oil.
If the pump has been in stock for a period before start-up, see
section 9.2 Service chart.
L1
L2
L3
N
PE
1
2
Checks before start-up
1. Check that the impeller is rotating in the correct direction.
2. Make sure that the pump is completely submerged in the
3. Make sure that there are no solid objects in the tank.
/I )
A N
Warning
When slackening the oil level screw, note that
pressure may have built up in the chamber.
Do not remove the screw until the pressure has
been fully relieved.
Fig. 20 Oil check and oil filling
See section 7.6 Direction of rotation.
liquid.
The pump must always be submerged during
Caution
operation.
Warning
Make sure that no persons can fall into the tank.
2
1 3
15