EBARA EVM serie Manual De Instrucciones página 20

15. SUPPLIED TECHNICAL DOCUMENTATION
15.1 STANDARD VOLTAGES SHOWN ON THE PLATE WITH THEIR RE-
SPECTIVE TOLERANCES
[kW] Frequency [Hz] Phase [~]
50
≤ 0.55
60
50
0.37 ÷ 4.0
EN
60
50
≥ 5.5
60
15.2 MOTOR OUTPUT REDUCTION FACTORS
When the motor-driven pump is installed in a site where the ambient tem-
perature is higher than 40°C and/or its altitude is over 1000 m above sea
level, the motor's output decreases.
The table attached features the reduction factors based on temperature
and altitude. To prevent overheating, you must replace the motor with a
different version whose rated output multiplied by the factor corresponding
to the temperature and altitude is greater than or equal to that of the stand-
ard motor.
The standard motor can only be used if the relevant application can accept
a reduction in flow rate, achieved by throttling the delivery line so as to re-
duce the current absorbed by an amount equal to the correction factor.
T(°C)
1000
40 1
45 0.95
50 0.92
55 0.88
60 0.83
65 0.79
15.3 MAXIMUM WORKING PRESSURE CHART
Maximum
EVMS1
working
pressure
50
1.6
2-26
2.5
27-39
Maximum
EVMS10
working
pressure
50
1.6
2-15
2.5
16-23
20
UN [V] ± %
230 ± 10%
1 ~
220 ± 10%
230 Δ / 400 Y ± 10%
3 ~
220 Δ / 380 Y - 5% /+ 10%
460 Y ± 10%
400 Δ / 690 Y ± 10%
3 ~
380 Δ - 5% /+ 10%
460 Δ ± 10%
Altitude (m.a.s.l.)
1500 2000
0.96 0.94
0.92 0.90
0.90 0.87
0.85 0.83
0.82 0.80
0.76 0.74
Pump model
EVMS3 EVMS5
Hz
60 50 60 50
2-18 2-21 2-15 2-17
20-29 23-33 16-23 19-27
Pump model
EVMS15 EVMS20
Hz
60 50 60 50
1-10 1-11 1-7 1-9
11-16 12-17 8-12 10-16
Maximum
working
pressure
1.6
2.5
3.0
15.4 AVOIDING CAVITATION
Cavitation, as you may know, is a destructive problem for pumps, a phe-
nomenon that is encountered when the water drawn in is transformed into
steam inside the pump. EVM pumps, fitted with internal hydraulic parts
made from stainless steel, suffer less than other pumps built with materials
of poorer quality, though they are not entirely immune to the damage that
cavitation brings.
Hence pumps must be installed in compliance with the laws of physics and
with rules relating to fluids as well as to the actual pumps.
Below we give you just the practical results of the above-mentioned rules
and laws of physics.
Under standard environmental conditions (15°C, at sea level), water turns
into steam when subjected to a negative pressure greater than 10.33 m.
Hence 10.33 m is the water's maximum theoretical suction height. EVM
pumps, like all centrifugal pumps, cannot exploit theoretical suction height
to the full owing to their internal loss, known as NPSHr, which has to be
deducted. Hence the theoretical suction lift of each EVM pump is 10.33 m
less its NPSHr at the work point in question.
The NPSHr can be determined by consulting the standard curves featured
in the brochures and must be taken into consideration when first selecting
2500
the pump.
When the pump is part of a flooded installation or has to draw cold water
0.90
from 1 or 2 m with a short pipe with one or more wide bends, NPSHr can
be disregarded. Consequently, the more difficult the installation, the more
0.88
the NPSHr value has to be taken into consideration. Installation becomes
0.85 difficult when:
a) Suction height is high;
0.81
b) Suction line is long and/or has lots of bends and/or has several valves
(high pressure losses along suction line);
0.77
c) Foot valve has high flow resistance (high pressure losses along suction
line);
0.72
d) Pump is used with a flow rate close to the maximum rated flow rate
(NPSHr increases as flow rate increases over the rate where efficiency
is highest);
e) Water temperature is high. (It is likely you will have to install the pump
with a flooded arrangement where values approach 80-85°C);
f) Altitude is high (in the mountains).
60
2-12
13-19
60
1-7
8-10
Pump model
EVM32 EVM45
Hz
50 60 50 60
1-7 1-5 1-3 1-4
8-12 6-8 4-9 5-6
13-14 8-10 10 –
EVM64
50 60
1-6 1-4
6-7 –
– –