English (GB)
14
7.5.3 Phase insulation, MG 71 and 80
MG motors, frame sizes 71 and 80, do not have phase insulation
as standard. The motors are not suitable for frequency converter
operation as they are not protected against the voltage peaks
caused by the frequency converter operation. Only motors with a
rated voltage equal to or above 460 V have phase insulation.
We recommend that you protect all other motors against voltage
peaks higher than 1200 V by 2000 V/μsec.
You can eliminate the above disturbances, i.e. both increased
acoustic noise and detrimental voltage peaks by fitting an LC filter
between the frequency converter and the motor.
For further information, contact the frequency converter or motor
supplier.
7.5.4 Other motor makes than those supplied by Grundfos
Contact Grundfos or the motor manufacturer.
8. Startup
Fig. 21 Vent valve, standard and an optional solution with
hose connection
Follow the instructions on page 351.
CR, CRI, CRN 1s to 5
For these pumps, we advise you to open the bypass valve during
startup. See fig. 22 for bypass valve location. The bypass valve
connects the inlet and outlet sides of the pump, thus making the
filling procedure easier. Close the bypass valve again when the
operation is stable.
When pumping liquids containing air, we advise you to leave the
bypass valve open if the operating pressure is lower than 6 bar.
Close the bypass valve if the operating pressure constantly
exceeds 6 bar. Otherwise the material at the opening will be worn
because of the high liquid velocity.
8.1 Shaft seal run-in
The seal faces are lubricated by the pumped liquid, meaning that
there may be a certain amount of leakage from the shaft seal.
When you start the pump for the first time, or when you install a
new shaft seal, a certain run-in period is required before the
leakage is reduced to an acceptable level. The time required for
this depends on the operating conditions, i.e. every time the
operating conditions change, a new run-in period will be started.
Under normal conditions, the leaking liquid will evaporate. As a
result, no leakage will be detected.
9. Maintenance
Pump bearings and shaft seal are maintenance-free.
Motor bearings
Motors not fitted with grease nipples are maintenance-free.
Motors fitted with grease nipples must be lubricated with a high-
temperature, lithium-based grease. See the instructions on the
fan cover.
In the case of seasonal operation where the motor is idle for more
than 6 months of the year, we recommend that you grease the
motor when you take the pump out of operation.
Depending on the ambient temperature, replace or lubricate the
motor bearings according to the table below. The table applies to
2-pole motors. The number of operating hours stated for bearing
replacement are guidelines only.
Intervals for 4-pole motors are twice as long as those for 2-pole
motors.
If the ambient temperature is lower than 40 °C, then replace or
lubricate the bearings at the intervals mentioned under 40 °C.
Frequency converter operation of MG motors without
phase insulation will cause damage to the motor.
Do not start the pump until it has been filled with
liquid and vented. If the pump runs dry, the pump
bearings and the shaft seal may be damaged.
TM05 1160 0611 - TM05 8098 1913
Warning
Pay attention to the direction of the vent hole and
make sure 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.
Warning
Make sure that a leakage does not cause injury to
persons or damage to the equipment.
Warning
Before starting work on the pump, make sure that all
power supplies to the pump have been switched off
and that they cannot be accidentally switched on.
Motor size
[kW]
Bearing replacement interval [operating hours]
40 °C 45 °C 50 °C 55 °C 60 °C
0.37 - 0.75 18000----
1.1 - 7.5 20000 15500 12500 10000 7500
Motor size
[kW]
Lubrication interval [operating hours]
40 °C 45 °C 50 °C 55 °C 60 °C
11 - 18.5 4500 3400 2500 1700 1100
22 4000 3100 2300 1500 1000
30-55 4000 3000 2000 1500 -
75 2000 1500 1000 500 -
