Electrical Connection; Checking The Direction Of Rotation - Grundfos Unilift AP12 Montage- Und Betriebsanleitung

3. Electrical connection

Depending on local regulations, a pump
with 10 metres of mains cable must be
Caution
used if the pump is used as a portable
pump for different applications.
The electrical connection must be carried out in
accordance with local regulations.
The pump must be connected to an external mains
switch. If the pump is not installed close to the
switch, the switch must be of a lockable type.
The operating voltage and frequency are marked on
the pump nameplate. Make sure that the motor is
suitable for the power supply on which it will be used.
Warning
As a precaution, the pump must be
connected to a socket with earth
connection. The permanent installation
must be fitted with an earth leakage circuit
breaker (ELCB) with a tripping current less
than 30 mA.
Warning
The protective earth of the socket outlet
must be connected to the protective earth
of the pump. The plug must therefore have
the same PE connection system as that of
the socket outlet. If not, use a suitable
adapter.
Three-phase pumps must be connected to an
external motor-protective circuit breaker with
differential release and with a minimum contact gap
of 3 mm. The set nominal current of the motor-
protective circuit breaker must correspond to the
electrical data marked on the pump nameplate.
If a level switch is connected to a three-phase pump,
the motor-protective circuit breaker must be
magnetically operated.
Single-phase pumps incorporate thermal overload
protection and require no additional motor
protection.
If the motor is overloaded, it will stop
automatically. When the motor has cooled
Note
to normal temperature, it restarts
automatically.

3.1 Checking the direction of rotation

Three-phase pumps only
Check the direction of rotation every time the pump
is connected to a new installation.
1. Position the pump so that you can observe the
impeller.
2. Start the pump for a short period.
3. Observe the rotation of the impeller. The correct
direction of rotation is indicated by an arrow on
the inlet strainer (clockwise when seen from the
bottom). If the impeller rotates in the wrong
direction, reverse the direction of rotation by
interchanging two of the phases to the motor.
If the pump is connected to a pipe system, check the
direction of rotation in this way:
1. Start the pump and check the quantity of water or
the pressure.
2. Stop the pump and interchange two of the
phases to the motor.
3. Start the pump and check the quantity of water or
the pressure.
4. Stop the pump.
Compare the results taken under points 1 and 3. The
connection which gives the larger quantity of water
or the higher pressure is the correct direction of
rotation.
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