Coupling Adjustment; Electrical Connection; Frequency Converter Operation - Grundfos CR 2 Instrucciones De Instalación Y Funcionamiento

In the case of installations in which the discharge pipe slopes
downwards away from the pump and there is a risk of siphon ef-
fect and in installations which must be protected against backflow
of unclean liquids, a vacuum valve must be fitted close to the
pump, see fig. 6.
Fig. 6
Minimum flows:
Liquid temperature
Pump type
Up to +80°C
CR, CRN 2 0.2 m³/h
CR, CRN 4 0.4 m³/h
CR, CRN 8 0.8 m³/h
CR, CRN 16 1.6 m³/h
Note: The pump must never operate against a closed discharge
valve.

6. Coupling adjustment

For adjustment of coupling in CR, CRN 2 and 4, see fig. F,
page 67.
For adjustment of coupling in CR, CRN 8 and 16, see fig. G,
page 68.
6
+120°C
+80°C +150°C
+120°C (only spe-
cial version)
0.5 m³/h -
1.0 m³/h -
2.0 m³/h -
4.0 m³/h -

7. Electrical connection

The electrical connection should be carried out by an authorized
electrician in accordance with local regulations.
Before removing the terminal box cover and before
any removal/dismantling of the pump, make sure that
the electricity supply has been switched off.
The pump must be connected to an external mains
switch with a minimum contact gap of 3 mm in all
poles.
The operating voltage and frequency are marked on the motor
nameplate. Make sure that the motor is suitable for the electricity
supply on which it will be used.
Single-phase GRUNDFOS motors incorporate a thermal switch
and require no additional motor protection.
Three-phase motors must be connected to a motor starter.
The terminal box can be turned to four positions, in 90° steps:
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.
The electrical connection should be carried out as shown in the
diagram inside the terminal box cover.

7.1 Frequency converter operation

Motors supplied by GRUNDFOS:
All three-phase motors supplied by GRUNDFOS can be con-
nected to a frequency converter.
Dependent on the frequency converter type, this may cause in-
creased acoustic noise from the motor. Furthermore, it may
cause the motor to be exposed to detrimental voltage peaks.
Note: GRUNDFOS motors types MG 71 and MG 80 as well as
MG 90 (1.5 kW, 2-pole), all for supply voltages up to and including
440 V (see motor nameplate), must be protected against voltage
peaks higher than 650 V (peak value) between the supply termi-
nals.
It is recommended to protect all other motors against voltage
peaks higher than 850 V.
The above disturbances, i.e. both increased acoustic noise and
detrimental voltage peaks, can be eliminated by fitting an LC filter
between the frequency converter and the motor.
For further information, please contact the frequency converter or
motor supplier.
Other motor makes than those supplied by GRUNDFOS:
Please contact GRUNDFOS or the motor manufacturer.