Operating Modes; Direction Of Rotation - Grundfos SEG Instrucciones De Instalación Y Operación

9.2 Operating modes

The pumps are designed for intermittent operation
(S3). When completely submerged, the pumps can
also run continuously (S1).
Fig. 8 Operating levels
S3, intermittent operation
S3 operation is a series of identical duty cycles (TC)
each with a constant load for a period, followed by a
rest period. Thermal equilibrium is not reached
during the cycle. See fig. 9.
P
Operation
Stop
Fig. 9 S3 operation
16
S1
S3
TC
S1, continuous operation
In this operating mode, the pump can run
continuously without having to be stopped for
cooling. Being completely submerged, the pump is
sufficiently cooled by the surrounding liquid. See fig.
10.
P
Operation
Stop
Fig. 10 S1 operation

9.3 Direction of rotation

The pump may be started for a very short
Note
period without being submerged to check
the direction of rotation.
All single-phase pumps are factory-wired for the
correct direction of rotation.
Before starting up three-phase pumps, check the
direction of rotation.
An arrow on the stator housing and an arrow at the
pump inlet indicate the correct direction of rotation.
Correct direction of rotation is clockwise when
viewed from above. When started, the pump will jerk
in the opposite direction of the direction of rotation.
If the direction of rotation is wrong, interchange two
phases. See fig. 5 or 6.
Checking the direction of rotation
Check the direction of rotation in one of the following
ways every time the pump is connected to a new
installation.
Procedure 1:
1. Start the pump and measure the quantity of liquid
or the discharge pressure.
2. Stop the pump and interchange two phases.
3. Restart the pump and measure the quantity of
liquid or the discharge pressure.
4. Stop the pump.
5. Compare the results taken under points 1 and 3.
The connection which gives the larger quantity of
liquid or the higher pressure is the correct
direction of rotation.
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