5.6.9 Frequency converter
Three-phase MS submersible motors can be
connected to a frequency converter.
To enable monitoring of the motor
temperature, Grundfos recommends
Note
installing a Pt100 sensor together with
a PR 5714 relay.
Permissible frequency ranges: 30-50 Hz and
30-60 Hz.
Ramp times: Maximum 3 seconds for start and stop.
Depending on the type, the frequency converter may
cause increased acoustic noise from the motor.
Furthermore, it may expose the motor to detrimental
voltage peaks. This can be compensated by
installing an LC filter or even better a sinus filter
between the frequency converter and the motor.
For further details, please contact your frequency
converter supplier or Grundfos.
6. Motor installation
Warning
Before starting work on the product,
switch off the power supply. Make sure
that the power supply cannot be
accidentally switched on.
7. Fitting the pump to the motor
1. Use pipe clamps when handling the motor.
Warning
When the motor is to be assembled with
the pump at the borehole, make sure to
use suitable pipe clamps.
2. Place the motor in vertical position at the
borehole. See fig. 15.
Fig. 15
Motor in vertical position
3. Lift the pump part by means of pipe clamps fitted
to the riser pipe. See fig. 16.
Fig. 16
Lifting the pump into position
4. Place the pump part on top of the motor.
5. Fit and cross-tighten the nuts to the torques
stated below.
Make sure that the coupling between
Caution
the pump and motor engages properly.
Pump/motor bolt diameter
5/16 UNF
1/2 UNF
M8
M12
M16
M20
Torque
[Nm]
18
50
18
70
150
280
17