5.7.6 Frequency converter
Three-phase MS submersible motors can be connected to
a frequency converter.
To enable the monitoring of the motor
temperature, Grundfos recommends the
Note
installation of 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
abated by installing an LC filter between the frequency converter
and the motor.
For further details, please contact your frequency converter
supplier or Grundfos.
6. Pump installation
Warning
Before starting any work on the pump/motor,
make sure that the electricity supply has been
switched off and that it cannot be accidentally
switched on.
6.1 Fitting the motor to the pump
When the pump part and the motor are supplied as separate units
(long pumps), fit the motor to the pump as follows:
1. Use pipe clamps when handling the motor.
2. Place the motor in vertical position at the borehole seal, see
fig. 18.
Fig. 18 Motor in vertical position
14
3. Lift the pump part by means of pipe clamps fitted to the
extension pipe, see fig. 19.
Fig. 19 Lifting the pump into position
4. Place the pump part on top of the motor.
5. Fit and tighten the nuts, see the table below.
Make sure that the coupling between the pump
Caution
and motor engages properly.
The bolts and nuts securing the straps to the pump must be
tightened diagonally to the torques stated in the following table:
Straps
bolt/nut
M8
M10
M12
M16
SP 215, 50 Hz, with more than 8 stages
SP 215, 60 Hz, with more than 5 stages
When fitting the motor to the pump part, the nuts must be
tightened diagonally to the torques stated in the following table:
Pump/motor
staybolt diameter
3/8 UNF
1/2 UNF
M8
M12
M16
M20
Make sure that the pump chambers are aligned
Caution
when assembly has been completed.
Torque
[Nm]
18
35
45
120
150
Torque
[Nm]
18
50
18
70
150
280