12
Translation of the original instructions
ENGLISH
VERTICAL MULTISTAGE ELECTRIC PUMPS
Always use the required PPE (refer to the relative section).
If required in relation to the conditions of use and the working environment, we
suggest installing adequate devices to immediately perform an emergency stop
of the machine.
4.1 Electrical connections
The connections must be exclusively performed by expert, authorised
personnel and in compliance with legal obligations, current regulations,
consolidated technical practices and the following provisions.
The appliance is designed exclusively for fixed applications (the power cable
cannot be disconnected and reconnected by the user).
Use electrical cables of type and section as per table A17 (in the appendix) and
relative cable glands. Open one of the passageways on the terminal block cover
and install the cable gland, tightening to the torque shown in the table. The end of
the conductors must be fitted with eyelet terminals (see table A17). The earthing
conductor must be longer than the other conductors (in case of cable pull, the
earthing conductor must be the last to be disconnected). Once wiring is complete,
remove the sponge under the terminal block.
The supply cable terminals must be connected in an electrical panel with at
least an IP55 protection rating, equipped with cable mechanical fixing systems
independent of electrical terminals, and an omni-polar cut off switch.
Make sure the rating plate details match the rated voltage and frequency values.
Always connect the earthing cable to the electric pump and check the earthing
circuit effectiveness before the first start-up and then every month.
The installer is responsible for making connections in accordance with the
regulations in force in the country of installation.
The appliance must be powered by a residual current device, with residual
operating current of no more than 30 mA.
Three-phase appliances must be protected against short-circuits and overloads
by a class 10 protection device, in accordance with IEC 60947-4. Set the rated
current according to the value shown on the rating plate. Use a manual reset
device.
4.2 Single-phase versions
Power the electric pump by using a single-pole, phase cut-off switch or a bipolar
switch. The direction of rotation of the electric pumps does not require any
checks. For bare shaft pumps, refer to the marking on the pump (fig A3).
4.3 Three-phase versions
Power the pump via an overvoltage category III omni-polar cut-off switch, to be
set up in the power supply line in accordance with the regulations in force.
CAUTION: Check which configuration of the electrical connections corresponds
to the available mains voltage on the rating plate and on the marking inside the
terminal block cover. If required, change the configuration by moving the jumpers
to the appropriate terminals (see fig. A17). At the end of the operation, check that
the electrical connections are secure and stable.
The direction of rotation must be checked by observing the motor on the cooling
fan side. Do not remove the protection devices to check the direction of rotation.
While checking the direction of rotation, run the motor for as short a time as
possible. If the direction of rotation cannot be visually checked, it is possible to
check it indirectly by installing the pump in the system and running it at maximum
flow rate (valves completely open, free delivery), according to one of the two
following modes:
• During operation, measure the maximum power consumption with an
ammeter clamp. If the direction of rotation is incorrect, the values will be nearly
double those specified on the rating plate.
• Alternatively, run the machine for a few seconds, then reverse the direction of
rotation and repeat the operation. The correct direction is the one in which the
greatest flow rate is obtained.
To reverse the direction of rotation, it is sufficient to swap two phases between
them.
4.4 Variable frequency drive (VFD) applications
For variable frequency installations (power supply via “inverter”), make sure the
frequency inverter can supply the rated voltage and at least 10% more current
than the rated value shown on the motor rating plate. To install and connect the
device, please refer to the manufacturer's instruction manual.
5 HYDRAULIC CONNECTIONS
Before starting any work on the electric pump or the motor, make sure
that the power supply is disconnected and it cannot be accidentally
restored.
Installing the electric pump can be complex and dangerous for people.
This operation must, therefore, be performed by competent, qualified
installers.
Refer to Fig. A5-A or A5-B in the appendix as the case may be. The pipe diameter
determines the flow rate and pressure available at the points of use. Small
diameter pipes increase noise, reduce performance and increase water hammers
and the risk of cavitation. Adopt larger flow cross-sections the longer the pipe
length, possibly with a larger diameter than that of the hydraulic connections of
the appliance. In this case, any diameter reductions along the horizontal sections
must be made with asymmetrical fittings (detail 6 in fig. A5), to facilitate air
escape. For the same reason, a pipe angle (about 3 cm/m, detail C in the figure)
of at least 2° is recommended in the direction of flow. If the electric pump extracts
from a non-pressurised line (e.g. a well or a tank, at a higher height than that of
the exposed surface) it is necessary to install a foot or non-return valve along the
suction pipe to prime the pump (3 in fig. A5). A mechanical filter may also be
necessary to protect the pump. The depth of the suction pipe must be sufficient to
prevent air from entering (detail 7 in fig. A5). For installations on pressurised lines
or negative suction head ones, also install a non-return valve before or after the
pump (5 in fig. A5) - to avoid emptying the delivery pipe following the shutdown
of the electric pump, and to avoid backflow - as well as a filter. If the machine is
connected to a closed hydraulic circuit, installing one or more vent valves at the
highest points of the circuit is recommended. Secure the pipes to the flanges of
the pump, without damaging them. Pay attention to the suction line pressure
which can be lower than the atmospheric one (risk of air entering through joints).
Make sure that the misalignment between pipes and outlets does not generate
an excessive load on the pump flanges. The force and momentum threshold
values on the connections are shown in figure A9, depending on the model. It
is recommended to install a flexible element on each side (2 in fig. A5), also in
order to limit the transmission of vibrations. The electric pump can be installed
with a pipe made of either metal or another material, provided it is mechanically
rigid and resistant to even the maximum operating temperature. Pipes must be
properly supported so as not to burden the pump flanges (detail 1 in fig. A5) and
must remain in position even with no pump. Install shut-off valves upstream and
downstream of the pump, to simplify maintenance operations (4 and 8 in fig. A5).
5.1 Checking the NPSH
Check the electric pump characteristic curves to evaluate the NPSH factor (see
Fig. A6) and thus prevent cavitation problems in case of a difference in height
between the pump and the level of the liquid to be drawn or for excessively high
temperature. The maximum height of the pump from the liquid level “H” (see fig.
A7-B) can be calculated with the following formula:
H = pb x 10.2 – NPSH – Hf – Hv – Hs
pb: Absolute barometric pressure or absolute pressure of the liquid on suction
[bar].
NPSH: Suction head at maximum flow rate capacity [m] (fig. A6)
Hf: Pressure drop in the suction pipe at maximum pump flow rate [m]
Hv: Vapour pressure [m] depending on the temperature of the liquid [m] (fig.
A7-A)
Hs: Safety margin [m] (minimum 0.5)
If the calculated value is less than “0”, the pump must be positioned below the
liquid level.
Example
pb = 1 bar
Pump type: EV 10
Flow rate: 9 m
3
/h
NPSH: 1.5 m (see fig A6)
Hf = 2.5 m
Liquid temperature: +50°C
Hv: 1.3 m (see fig. A7-A)
H = pb x 10.2 NPSH-Hf-Hv-Hs [m]. = 1 x 10.2-1.5-2.5-1.3-0.5 = 4.4 [m]
This means that the height of the pump from the level of the liquid to be drawn
must not exceed 4.4 meters
5.2 Maximum pressure check
Operating pressure
The sum of the inflow pressure (p1) and the maximum pressure produced
by the pump must always be lower than the maximum operating pressure
Pmax, indicated on the rating plate.
Case 1: Single standard pump (fig. A8-A)
P1 [bar]+ Hmax [m]/10 <= Pmax [bar]
Case 2: Standard pump + high pressure pump (fig. A8-B)
P1 [bar]+ Hmax,1[m] /10 <= Pmax,1 [bar]
P1 [bar]+ Hmax,1[m] /10 + Hmax,2[m] /10 <= Pmax,2 [bar]
