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Installation and operating instructions • Wilo-Flumen OPTI-TR 50-3 ... 120-1, Wilo-Flumen EXCEL-TRE 50-3 ... 90-2 • Ed.01/2022-07
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13.2
Frequency converter operation
The motor in series design (confirming to IEC 60034‑17) can be operated with a frequency
converter. Contact customer service if the rated voltage is above 415 V/50 Hz or
480 V/60 Hz. Because of the additional heating caused by harmonics, the rated power of
the motor should be around 10 % more than the power requirement of the mixer. For fre-
quency converters with a low-harmonic output, it is possible to reduce the 10 % power re-
serve. Harmonic waves are reduced by means of output filters. Synchronise the frequency
converter and the filter with each other!
The configuration of the frequency converter depends on the rated motor current. Make
sure that the mixer operates across the entire control range without jerking or vibrating
(without vibrations, resonance, oscillation). Otherwise, the mechanical seals may leak or be
damaged. Increased motor noise caused by the harmonics of the power supply is normal.
During parameterisation of the frequency converter, observe the setting of the quadratic
characteristic curve (U/f characteristic curve) for submersible motors! The U/f characteristic
curve ensures that the output voltage at frequencies less than the rated frequency (50 Hz
or 60 Hz) is adjusted to the power requirement of the mixer. More recent frequency con-
verters feature an automatic power optimisation function - this automation achieves the
same effect. For the frequency converter setting, refer to its installation and operating in-
structions.
Motor monitoring faults may occur if the motor is operated with a frequency converter. The
following measures can reduce or avoid these faults:
•
Keeping within the limit values stated in IEC 60034‑25 for overvoltage and rise speed. If
necessary, install output filters.
•
Vary the pulse frequency of the frequency converter.
•
In the event of a fault in the internal sealing chamber monitoring, use the external
double-rod electrode.
The following construction measures can help to reduce or prevent faults:
•
Separate connection cables for the main and control cable (depending on the motor
size).
•
Keep an adequate distance between main and control cable during routing.
•
Use shielded connection cables.
Summary
•
Min./max. frequency during continuous duty:
–
Asynchronous motors: 30 Hz up to rated frequency (50 Hz or 60 Hz)
–
Permanent magnet motors: 30 Hz up to the stated maximum frequency as per rating
plate
NOTICE! Higher frequencies are possible following consultation with customer
service!
•
Observe additional measures with regard to EMC regulations (choice of frequency con-
verter, using filters, etc.).
•
Do not exceed the rated current or rated speed of the motor.
•
Connection for bimetallic strip or PTC sensor.
13.3
Ex rating
This section contains further information on the operation of the mixer in an explosive at-
mosphere. All personnel must read this section.
This section applies only to Ex-rated mix-
ers!
13.3.1
Identification of Ex-rated mixers
If the mixer is approved for use in explosive atmospheres, this is marked on the rating plate
as follows:
•
“Ex” symbol of the corresponding approval
•
Ex classification
•
Certification number (depending on the approval)
If the approval requires this, the certification number will be printed on the rating plate.
13.3.2
Protection class
The motor’s design version corresponds to the following protection classes:
•
Flameproof enclosure (ATEX)
•
Explosionproof (FM)
•
Flameproof enclosures (CSA-EX)
In order to limit the surface temperature, the motor must be equipped with at least one
temperature limiter (1‑circuit temperature monitoring). It may also be equipped with a
temperature controller (2‑circuit temperature monitoring).
