Single-Phase Connection; Terminal Box Positions; Frequency Converter Operation - Grundfos CR Series Installation And Operating Instructions Manual

7.3 Single-phase connection

"Low voltage"
50 Hz 220-230
Fig. 17 Connection, "low voltage", 0.37 - 0.75 kW
Fig. 18 Connection, "high voltage", 0.37 - 0.75 kW
Fig. 19 Connection, "low voltage", 1.1 - 2.2 kW
Fig. 20 Connection, "high voltage", 1.1 - 2.2 kW
Single-phase Grundfos motors incorporate a thermal switch and
require no additional motor protection.
10
Mains supply [V]
"High voltage"
/ 240

7.4 Terminal box positions

You can turn the terminal box to four positions, in 90 ° steps.
Follow this procedure:
1. If necessary, remove the coupling guards. Do not remove the
coupling.
2. Remove the bolts securing the motor to the pump.
3. Turn the motor to the required position.
4. Replace and tighten the bolts.
5. Replace the coupling guards.
Carry out the electrical connection as shown in the diagram
inside the terminal box cover.

7.5 Frequency converter operation

You can use 3-phase motors for frequency convertor operation
following the conditions below. This section applies to motors
defined in IEC 60034.
7.5.1 General conditions
Protect all motors used with frequency converters against voltage
peaks and dU/dt according to IEC 60034-17. Grundfos
recommends that you use insulated bearings for motors from
frame size 225 (45 kW/2-pole, 30 kW/4-pole and 22 kW/6-pole).
Mains voltage dependent conditions
200-240 V
No output filters are required for frequency converter operated
motors with mains voltages up to 240 V.
380-500 V
For frequency converter operated motors with motor cable length
less than 25 metres and mains supply up to 460 V. No additional
motor protection against voltage peaks is required. For frequency
converter operated motors with motor cable length of more than
25 metres or mains supply higher than 460 V, sine-wave filters
are required.
500 V and higher
Always use sine-wave filters for motors marked with 500 V or
higher voltages. *
Exception
• Protect Grundfos motors types MG 71 and MG 80 (up to 1.1
kW/2-pole and up to 0.75 kW/4-pole) for supply voltages up to
and including 440 V without phase insulation against voltage
peaks above 650 V between the supply terminals.
• If you use MG 71 and MG 80 without phase insulation for input
voltages above 240 V, it requires that you use sine save filters
at the output of the frequency converter.
• MG 71 and MG 80 with phase insulation for use with variable
frequency drives are available as standard products.
* Motors with reinforced insulation can be supplied as an option.
These motors are according to IEC 60034-25 and therefore there
is no need for sine-wave filters. This do not eliminate the
requirement for insulated bearings from frame size 225.
7.5.2 Motors supplied by Grundfos
You can connect all three-phase MG motors with phase insulation
to a frequency converter.