Installing An External Frequency Converter; Dry-Running Protection - Wilo Sub TWU 3 HS Serie Einbau- Und Betriebsanleitung

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The following points must be observed when
doing this:
• Nylon or stainless steel guys are used to lower the
pump.
• The guy must have sufficient bearing capacity for
the complete system (pump, piping, cable, water
column).
• The guy must be fastened to the suspension
points (eyelets) provided on the pressure port
for that purpose. If these suspension points are
not available, an intermediate flange containing
suspension points must be installed.
DANGER due to improper fixation.
The guy must not be wound around the pres-
sure port or affixed to the piping. This could
result in slipping or the piping might become
separated. There is an increased risk of injury!
Always fasten the guy to the prescribed sus-
pension points.
5.3.3. Horizontal installation of the pump
This installation method is only permissible in
conjunction with a cooling jacket. The pump is
installed directly in the tank/reservoir and flanged
onto the discharge pipeline. The cooling jacket's
supports have to be installed at the specified
distance in order to prevent bending of the unit.
For more information, see the installation and
operating instructions for the cooling jacket in
question.
The connected piping must be self-supporting,
i.e. it must not be supported by the unit.
In the case of horizontal installation, the pump
and piping are installed separately. Make sure
that the pressure connection for the pump and
the pressure connection for the piping are at the
same height.
1. Drill the mounting holes for the support into the
floor of the operating space (tank/reservoir). See
the relevant instructions for information about
the anchor bolts, distances between holes and
size of holes. Pay attention to the required tight-
ness of screws and anchors.
2. Fasten the supports to the floor and move the
pump into the correct position using suitable
hoisting gear.
3. Fasten the pump to the supports with the fixation
material provided. Make sure that the rating plate
faces upwards.
4. Once the pump has been firmly installed, the pipe
system can be mounted or a pipe system installed
previously can be attached. Make sure that the
pressure connections are at the same height.
5. Connect the discharge pipe to the pressure con-
nection. The threaded connection must be sealed.
Make sure that the pipe system was installed
vibration-free and stress-free (if necessary, use
elastic adaptors).
6. Lay the cable in such a way that it does not pose
a danger to anyone (maintenance personnel, etc.)
at any time (during operation, during mainte-
nance work, etc.). The power supply cables must
38
not be damaged. The electrical connections must
be carried out by an authorised expert.

5.3.4. Installing an external frequency converter

Fig. 4.: Description
1 Inlet
2 Pressure connection
The frequency converter is installed directly in
the piping so that it is cooled by the fluid being
pumped during operation.
Note the following:
• Ambient conditions:
• Ambient temperature: 4...40 °C (frost-proof)
• Fluid temperature: 3...35 °C
• Protection class: IP X5 (overflow-proof instal-
lation).
• The electrical connection and all settings are
carried out on the frequency converter itself. It
therefore needs to be easily accessible.
• During installation, note the direction of flow.
See the direction of flow arrow on the frequency
converter's housing.
NOTE:
The pressure and inlet connection on the
frequency converter is sized G 11/4, the pressure
connection on the pump is sized Rp 1. Depend-
ing on the discharge pipeline, 1 or 2 adaptors
need to be installed after the frequency con-
verter by the customer.

5.4. Dry-running protection

Submersible pumps are cooled by the fluid.
Therefore, the motor must always be immersed.
In addition, make sure that no air enters the
hydraulics housing. The pump must therefore al-
ways be immersed in the fluid up to the top edge
of the hydraulic housing. For optimum operational
reliability, we recommend installing a dry-running
protection system.
The TWU 3-...-HS has a built-in dry-running pro-
tection in the frequency converter. If the water
level fluctuates strongly, the motor's maximum
switching cycles may be exceeded. This could
lead to overheating of the motor. We there-
fore recommend providing an additional onsite
dry-running protection in this case.
Dry-running protection is provided with the help
of electrodes or level sensors. The signal trans-
mitter is fixed in the borehole/basin and switches
off the pump when the water level falls below the
minimum water submersion.
5.4.1. Remedies for avoiding excessive switching
cycles
Manual reset – the motor is switched off when
the water level falls below the minimum cover-
age level and switched back on when a sufficient
water level is reached.
INSTALLATION
3 Direction of flow arrow
WILO SE 05/2014 Ed.04 DIN A4