Checking The Direction Of Rotation - Grundfos UNILIFT AP12 Installation And Operating Instructions Manual

Make sure that the product is suitable for the supply
voltage and frequency available at the installation
site. Voltage and frequency are marked on the pump
nameplate.
The pump must be connected to an external main
switch. If the pump is not installed close to the switch,
the switch must be of a lockable type.
Three-phase pumps must be connected to an
external motor-protective circuit breaker with
differential release. The rated 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 auto-
matically. When the motor has cooled to
normal temperature, it restarts automati-
cally.
Wiring diagram
Pos. Description
1 Yellow and green
2 Grey
3 Brown
4 Black
N L
1 2
M
1~
Wiring diagram
-
3
Pos. Description
1 Yellow and green
2 Blue
3 Brown

4.1 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
largest quantity of water indicates the correct
direction of rotation.
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