Applications; Pumped Liquids; Operating Conditions; Ambient Temperature And Altitude - Grundfos NB Series Installation And Operating Instructions Manual

5. Applications

5.1 Pumped liquids

Clean, thin, non-explosive liquids without solid
particles or fibres. The pumped liquid must not attack
the pump materials chemically.

6. Operating conditions

6.1 Ambient temperature and altitude

The ambient temperature and the installation altitude
are important factors for the motor life as they affect
the life of the bearings and the insulation system.
If the ambient temperature exceeds the
recommended maximum ambient temperature or the
installation altitude exceeds the recommended
maximum altitude above sea level, see fig. 6, the
motor must not be fully loaded due to the low density
and consequently low cooling effect of the air. In
such cases, it may be necessary to use a motor with
a higher output.
P2
[%]
100
90
80
70
60
50
20 25 30 35 40 45 50 55 60 65 70 75 80
1000
Fig. 6 The maximum motor output depends on
the ambient temperature and altitude
Legend
Pos. Description
1 0.25 - 0.55 kW MG motors
0.75 - 22 kW MG motors, IE2/IE3
2
0.75 - 450 kW MMG-H motors, IE2
3 0.75 - 462 kW Siemens motors, IE2
Example
A pump with a 1.1 kW IE2 MG motor: If this pump is
installed 4750 m above sea level, the motor must not
be loaded more than 88 % of the rated output. At an
ambient temperature of 75 °C, the motor must not be
loaded more than 78 % of the rated output. If the
pump is installed 4750 m above sea level at an
ambient temperature of 75 °C, the motor must not be
loaded more than 88 % x 78 % = 68.6 % of the rated
output.
3
2
1
t [°C]
2250 3500 4750 m

6.2 Liquid temperature

-40 - +140 °C.
The maximum liquid temperature is stated on the
pump nameplate. It depends on the shaft seal
chosen.
For EN-GJL-250 cast-iron pump housings, local
regulations may not allow liquid temperatures above
+120 °C.

6.3 Max. operating pressure

Maximum operating pressure, i.e.
pressure above atmospheric pressure
Pump pressure
Inlet pressure
Fig. 7 Pressures in the pump
The inlet pressure + the pump pressure must be
lower than the maximum operating pressure stated
on the pump nameplate. Operation against a closed
valve gives the highest operating pressure.
11