Checking The Direction Of Rotation - Grundfos DPK Montage- Und Betriebsanleitung

The pumps are designed for intermittent operation
(S3). When completely submerged, the pumps can
also operate continuously (S1).
Fig. 5 Operating levels of DPK
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. 6.
P
Operation
Stop
Fig. 6 S3 operation
S1, continuous operation
In this operating mode, the pump can operate
continuously without being stopped for cooling.
Being completely submerged, the pump is
sufficiently cooled by the surrounding liquid. See fig.
7.
P
Fig. 7 S1 operation
12
S1
S3
TC
t

4.2 Checking the direction of rotation

Only start and run an unsubmerged pump
for a few seconds to check the direction of
rotation.
Check the direction of rotation in the following way
every time the pump is connected to a new
installation.
Proceed as follows:
1. Remove the pump from the system. Let the pump
hang from a lifting device, for example the hoist
used for lowering the pump into the pit.
2. Start and run the pump for a few seconds.
3. Observe the jerk of the pump. If the pump jerks
counterclockwise, the direction of rotation is
correct. See fig. 8.
4. Reinstall the pump in the system.
In case the direction of rotation is wrong, interchange
any two phases in the power cable.
Fig. 8 Jerk direction