Frequency Converter Operation; Starting Up The Product; Before Starting The Product; Starting The Product - Grundfos CRK 2 Montage- Und Betriebsanleitung

Three-phase motors must be connected to a motor-
protective circuit breaker.
The terminal box can be turned to four positions, in
90 ° steps. See fig. 8.
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.
270˚
180˚
Fig. 8 Terminal box positions

3.3.1 Frequency converter operation

Motors supplied by Grundfos
All three-phase motors supplied by Grundfos can be
connected to a frequency converter.
Depending on the frequency converter type, this may
cause increased acoustic noise from the motor.
Furthermore, it may cause the motor to be exposed
to detrimental voltage peaks.
Grundfos motors, types MG 71 and MG 80
as well as MG 90 (1.5 kW, 2-pole), 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 terminals.
We recommend 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
If other motors makes than those supplied by
Grundfos are used, contact Grundfos or the motor
manufacturer.
0˚
90˚

4. Starting up the product

WARNING
Too high pressure and leakage
Death or serious personal injury
• Do not run the pump against a closed
outlet valve for more than approx. 5
minutes.

4.1 Before starting the product

• Make sure that all pipe connections are tight.
• Make sure that the pump is partly filled with liquid
(partly submerged).
• Make sure that the strainer is not blocked by
impurities.

4.2 Starting the product

1. Close the isolating valve on the outlet side of the
pump.
2. If the pump is fitted with an vent valve, this valve
must be opened. See fig. 9.
Fig. 9 Position of the vent valve
3. See the correct direction of rotation of the pump
on the motor fan cover or on the coupling guard.
When seen from the top, the pump must rotate
counterclockwise.
4. Start the pump and check the direction of
rotation.
5. Open the outlet pipe isolating valve a little.
6. If the pump is fitted with an vent valve, this valve
must be closed when a steady flow of liquid runs
out of it.
7. Completely open the outlet pipe isolating valve.
The pump has now been vented and is ready for
operation.
Vent valve
9