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

10.2 Operating modes

The pumps are designed for intermittent operation (S3). When
completely submerged, the pumps can also run continuously
(S1).
Operating levels
Fig. 7
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. 8. In this
operating mode, the pump is partly submerged in the pumped
liquid, i.e. the liquid level reaches at least the middle of the motor.
See fig. 7.
P
Operation
Stop
S3 operation
Fig. 8
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.
9.
P
Operation
Stop
S1 operation
Fig. 9
14
S1
S3
TC
t

10.3 Direction of rotation

The pump may be started for a very short period
Note
Note
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. 4 or 5.
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 outlet
pressure.
2. Stop the pump and interchange two phases.
3. Restart the pump and measure the quantity of liquid or the
outlet 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.
Procedure 2
1. Let the pump hang from a lifting device, e.g. the hoist used for
lowering the pump into the pit.
2. Start and stop the pump while observing the movement (jerk)
of the pump.
3. If connected correctly, the pump will jerk in the opposite
direction of the direction of rotation. See fig. 10.
4. If the direction of rotation is wrong, interchange two phases.
See fig. 4 or 5.
Fig. 10 Jerk direction