Biral SUB4X — guidelines for Operating Submersible Pumps with Soft Starters and Inverters [19/60]

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Biral SUB4X [19/60] English
The submersible pump is suitable for operation
with a soft starting unit (soft starter).
The following conditions or limits must be observed:
Starting voltage set: 220 V (55%) of UN 400 V
Slope time: optimally 1 second
but a maximum of 3 seconds
The soft starting control must be bypassed after
running up with a bypass contactor.
5.4 Operation with frequency converter (inverter)
Submersible pumps can be operated with frequency
converters if the following guidelines are observed.
Experience shows that it is advisable to make the
frequency converter one size too large. This permits
the following requirements to be reliably satisfied:
The rated current must not be exceeded at rated
voltage and frequency.
The operating frequency lies between 30 Hz
and rated frequency (50 Hz).
The slope time from 0 Hz to 30 Hz
a maximum of 1 second
The voltage rise - voltage peaks (dV/dt) should be
less than 500 V/Ìsec (EN 60034).
A suitable sine-wave filter must be fitted
(note FU manufacturer data).
Alternatively, an inductor (LC filter)
may also be used
Reduction of the nominal delivery to less
than 10% is not permitted.
The thermal loading of the motor must be calculated
and monitored by the FC (ETR - Electronic Thermal
Relay) so that it does not overheat.
Starting voltage, starting current and slope time
are given in the following table 1.
Table 1:
english
19
Shaft output Soft-starting unit
P2 (motor) frequency converter (FU)
V
S min IS min max.
slope time
[kW] [%Vn] [% In] [s]
0.37 to 5.5 60 1
7.5 to 37 1.5
45 to 59 2
66 to 92 70 250 2.5
110 to 170 3
190 to 370 3.5
V
S = starting voltage
Vn = rated voltage
I
S = starting current
IN = rated current
6. Commissioning, checking operation
6.1 Measuring the insulation resistance
Measurement of insulation resistance determines
the resistance between all individual phases and earth.
For this test the motor must be electrically isolated
from the installation (disconnect underwater cable on
control side). The resistance between the individual
phases
and earth is measured with an ohmmeter or insulation
measuring set (test voltage 500 VDC).
Minimum value required:
–0,5 MΩ (fitted in well)
6.2 Commissioning
If the direction of rotation is wrong, the submersible
pump will never attain the correct hydraulic values.
The following procedure should be adopted to check
the direction of rotation:
1.
Measure the pressure against the closed slide valve.
(Caution: the pump should only be operated briefly
against the closed valve - 2 minutes maximum).
2. Disconnect all poles of the mains voltage and
secure against re-connection. Change over 2 of
the 3 phases.
3. Repeat point 1.
4. The correct direction of rotation is that which
develops the higher pressure.
(Maximum pressure is equivalent to correct
direction of rotation!)
Warning
Submersible pumps must never be
allowed to run dry!
The characteristic curve of the pump
must be observed. It will be destroyed
if the motor is overloaded.
The riser pipe (pressure pipe) should be
vented before putting into service to
avoid water hammer when running-up.
Warning
Operation of the pump against a slide
valve throttled too much results in damage
to the axial bearing and overheating
of the motor due to insufficient cooling.
If the system counter-pressure is
inadequate (e.g. slide valve/control
element opened too far) the pump
is operated outside the characteristic
curve and the motor is overloaded
1. Vent pipe and switch on pump with slide valve
practically closed (not with slide valve fully closed).
1.1 Allow a long pause between successive starts to
prevent the motor overheating. The maximum
number of starts per hour must not be exceeded.
Look for cause of fault
2. Open slide valve slowly and regulate to operating
point specified. Check current consumption
with slide valve fully open. This must be less
than the rated current.
6.3 Checking direction of rotation
Warning
The direction of rotation cannot be
checked or determined from the current
consumption.
With soft starting units one phase
is always connected through directly.
5.3 Operation with soft start unit

Содержание

Learn how to operate submersible pumps effectively using soft starters and frequency converters. Follow essential guidelines for optimal performance and safety.

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