20
EN
15.4 CAVITATION
Cavitation, as you may know, is a destructive problem for pumps, a phenomenon
that is encountered when the water drawn in is transformed into steam inside the
pump. EVMS 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. EVMS 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 EVMS 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 the pump.
When the pump is part of a flooded installation or has to draw cold water 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 the NPSHr value has to
be taken into consideration. Installation becomes difficult when:
a) Suction height is high;
b) Suction line is long and/or has lots of bends and/or has several valves (high
pressure losses along suction line);
c) Foot valve has high flow resistance (high pressure losses along suction line);
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).
15.5 POSITIONING OF HOLES FOR FASTENING DOWN
15. SUPPLIED TECHNICAL DOCUMENTATION
15.1 STANDARD VOLTAGES SHOWN ON THE PLATE WITH THEIR
RESPECTIVE TOLERANCES
15.2 MOTOR OUTPUT REDUCTION FACTORS
When the motor-driven pump is installed in a site where the ambient temperature
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 standard 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 reduce the
current absorbed by an amount equal to the correction factor.
T(°C)
Altitude (m.a.s.l.)
1000
1500
2000
2500
40
1
0.96
0.94
0.90
45
0.95
0.92
0.90
0.88
50
0.92
0.90
0.87
0.85
55
0.88
0.85
0.83
0.81
60
0.83
0.82
0.80
0.77
65
0.79
0.76
0.74
0.72
15.3 MAXIMUM WORKING PRESSURE CHART
Pressure indicated according to the number of impellers.
Pmax
50 Hz
EVMS1
EVMS3
EVMS5
EVMS10
EVMS15
1.6
2 ÷ 26
2 ÷ 21
2 ÷ 17
2 ÷ 15
1 ÷ 11
2.5
27 ÷ 39
23 ÷ 33
19 ÷ 27
16 ÷ 23
12 ÷ 17
Pmax
50 Hz
EVMS20
EVMS32
EVMS45
EVMS64
EVMS90
1.6
1 ÷ 9
1 ÷ 7
1 ÷ 5
1 ÷ 5
1 ÷ 4
2.5
10 ÷ 16
8 ÷ 11
6 ÷ 9
6 ÷ 8
5 ÷ 6
3.0
-
12 ÷ 14
-
-
-
3.5
-
-
10 ÷ 13
-
-
Pmax
60 Hz
EVMS1
EVMS3
EVMS5
EVMS10
EVMS15
1.6
2 ÷ 18
2 ÷ 15
2 ÷ 12
1 ÷ 10
1 ÷ 7
2.5
20 ÷ 29
16 ÷ 23
13 ÷ 19
11 ÷ 16
8 ÷ 12
Pmax
60 Hz
EVMS20
EVMS32
EVMS45
EVMS64
EVMS90
1.6
1 ÷ 6
1 ÷ 5
1 ÷ 4
1 ÷ 3
1 ÷ 3
2.5
7 ÷ 10
6 ÷ 8-2
5 ÷ 6
4 ÷ 5
4
3.0
-
8-0 ÷ 10
-
-
-
3.5
-
-
7
-
-
[kW]
Frequency
[Hz]
Phase
[~]
UN [V] ± %
≤ 0.55
50
1 ~
230 ± 10%
60
220 ± 10%
0.37 ÷ 4.0
50
3 ~
230 Δ / 400 Y ± 10%
60
220 Δ / 380 Y - 5% /+ 10%
460 Y ± 10%
≥ 5.5
50
3 ~
400 Δ / 690 Y ± 10%
60
380 Δ - 5% /+ 10%
460 Δ ± 10%
Summary of Contents for EVMS 1
Page 85: ...85 12 13 14 9 8 10 11 A EVMS 1 3 5 10 15 20 3 Nm...
Page 87: ...87 A EVMS 32 45 64 90 without ball bearing 9 10 11 12 13 14 15 5 Nm 2 min...
Page 88: ...88 A EVMS 32 45 64 90 with ball bearing 2 min 1 2 3 4 5 7 6 M8 20 Nm M12 40 Nm M16 70 Nm...
Page 91: ...91 E EVMS 1 3 5 10 15 20 4 kW 1 2 3 4 5 6 7 8 9 10 3 Nm M6 10 Nm 11 12...
Page 92: ...92 E EVMS 1 3 5 10 15 20 5 5 kW 1 2 3 4 5 6 7 8 9 10 11 12 3 Nm M8 18 Nm M10 50 Nm...
Page 97: ...97...
Page 98: ...98...
Page 99: ...99...
