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9. Technical data
9.1 Operating conditions
9.1.1 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.
Ambient temperature must not 40 °C.
If the ambient temperature e40 °C or the
motor is installed more than 1000 m above sea level,
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.
Fig. 24
Relationship between motor output (P
2
)
and ambient temperature
Example
The upper figure shows that the load of the motor
must be reduced to 88 % when installed 3500 m
above sea level. At an ambient temperature of 70 °C,
the motor load must be reduced to 78 % of the rated
output.
In cases where both the maximum temperature and
the maximum altitude are exceeded, the derating
factors must be multiplied (0.88 x 0.78 = 0.69).
9.1.2 Liquid temperature
The maximum liquid temperature marked on the
pump nameplate depends on the mechanical shaft
seal used:
9.1.3 Pressure in the pump
Fig. 25
Pressure in the LSV pump
Maximum outlet pressure
Minimum inlet pressure
The minimum inlet pressure must correspond to the
NPSH curve for the pump + a safety margin of
minimum 0.5 metres head.
NPSH appears from the data booklet and Grundfos
Product Centre.
Maximum inlet pressure
The inlet pr pump pressure must be lower
than the maximum pressure p of the pump.
9.1.4 Flow rate
Minimum flow rate
The pump must not run against a closed outlet valve
as this will cause an increase in temperature or
formation of steam in the pump. This may cause
shaft damage, impeller erosion, short life of
bearings, damage to stuffing boxes or mechanical
shaft seals due to stress or vibration.
The continuous flow rate must be at least 25 % of the
flow rate in the best efficiency point.
Maximum flow rate
The maximum flow rate must not exceed the value
stated on the nameplate. If the maximum flow rate is
exceeded, cavitation and overload may occur.
Operating at reduced flow and/or head
Do not operate the pump at a flow rate below 10 % of
the maximum flow rate stated on the nameplate or
with the outlet isolating valve or throttle valve closed.
Operating the pump under such conditions may
involve the risk of the pump being overheated. To
prevent possible damage, use protective devices
such as liquid temperature relay, bearing
temperature relay, inlet pressure monitoring.
If a pump is operated at reduced head, the flow rate
will increase and the motor will consume more
current than normal. This will result in overheating of
the motor. In such situations, throttle the valve on the
outlet side instead. If an automatic throttle valve is
installed, this can be done automatically.
9.1.5 Frequency of starts and stops
The recommended maximum number of starts is 3
per hour for complete pumps with a motor supplied
by Grundfos.
TM0
0
2
18
9 1
5
9
8
Temperature range for NBR: 0-100 °C
Temperature range for FKM: 15-100 °C
T
M
04
0
0
6
2
49
07
20 25 30 35 40 45 50 55 60 65 70 75
80
50
60
70
80
90
100
[%]
P1
t [°C]
1000
2250
3500 m
Inlet pressure
Pump pressure
Pressure p stated on the pump
(pressure above atmospheric
pressure)
The maximum outlet pressure is the
pressure p stated on the pump nameplate.
Summary of Contents for LSV Series
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