Terminal Box Position; Frequency Converter Operation; Start-Up - Grundfos CRT Serie Instrucciones De Instalación Y Funcionamiento

7.4 Terminal box position

The terminal box can be turned 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. Fit and tighten the bolts.
5. Fit the coupling guards.
6. Carry out the electrical connection as shown in the diagram
inside the terminal box cover.

7.5 Frequency converter operation

Motors supplied by Grundfos
All three-phase motors supplied by Grundfos can be connected to
a frequency converter. The frequency converter must be set to
variable torque.
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, for
supply voltages up to and including 440 V
without phase insulation (see motor nameplate)
Caution
must be protected against voltage peaks above
650 V (peak value) between the supply terminals.
We recommend to protect all other motors against voltage peaks
higher than 1200 V by 2000 V/μsec.
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.

8. Start-up

Do not start the pump until it has been filled with
liquid and vented. If the pump runs dry, the pump
Caution
bearings and the shaft seal may be damaged.
Warning
Pay attention to the direction of the vent hole and
take care to ensure that the escaping water does
not cause injury to persons or damage to the
motor or other components.
In hot-water installations, pay special attention to
the risk of injury caused by scalding hot water.
Step
1
2
3
4
5
6
7
Action
Close the isolating valve on the
discharge side of the pump and
open the isolating valve on the
suction side.
Remove the priming plug from
the pump head and slowly fill
the pump with liquid.
Fit and tighten the priming plug.
See the correct direction of
rotation of the pump on the
motor fan cover.
Start the pump and check the
direction of rotation.
Vent the pump by means of the
vent valve in the pump head.
At the same time, open the
discharge isolating valve a little.
Continue to vent the pump.
At the same time, open the
discharge isolating valve a little
more.
Close the vent valve when a
steady stream of liquid runs out
of it. Completely open the
discharge isolating valve.
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