Ex Rating; Identification Of Ex-Rated Pumps; Protection Class - Wilo Rexa PRO Serie Instrucciones De Instalación Y Funcionamiento

13.2

Ex rating

13.2.1

Identification of Ex-rated pumps

13.2.2

Protection class

Installation and operating instructions Wilo-Rexa PRO
Appendix
the lower speed range. Otherwise, the mechanical seals can leak or be damaged. Also con-
sider the flow rate in the pipe. If the flow rate is too low, the risk of solids depositing in the
pump and piping increases. A minimum flow rate of 0.7 m/s (2.3 ft/s) with a pumping pres-
sure of 0.4 bar (6 psi) is recommended.
It is important that the pump operates across the entire control range without vibrations,
resonance, oscillation or excessive noise. Increased motor noise caused by the harmonics of
the power supply is normal.
During parameterization of the frequency converter, observe the setting of the quadratic
pump curve (U/f curve) for pumps and fans! The U/f curve ensures that the output voltage at
frequencies less than the rated frequency (50 Hz or 60 Hz) is adjusted to the power require-
ment of the pump. Newer frequency converters feature an automatic power optimization
function - this automation achieves the same effect. For the frequency converter setting,
refer to its installation and operating instructions.
Faults with the motor monitoring may occur on motors operated with a frequency converter
depending on the type used and installation conditions present. The following measures can
help to reduce or avoid these faults:
▪ Keeping within the limit values stated in IEC 60034‑25 for the voltage peaks and rise speed.
Output filters may need to be installed.
▪ Vary the pulse frequency of the frequency converter.
▪ In the event of a fault on the internal sealing chamber control, use the external double-rod
electrode.
The following construction measures can also help to reduce or prevent faults:
▪ Separate power supply cables for the main and control cable (depending on the motor size).
▪ When laying, ensure there is adequate clearance between the main and control cable.
▪ Use shielded power supply cables.
Summary
▪ Continuous duty up to rated frequency (50 Hz or 60 Hz), observing the minimum flow veloc-
ity.
▪ Observe additional measures with regard to EMC regulations (choice of frequency converter,
using filters, etc.).
▪ Never exceed the rated current or rated speed of the motor.
▪ It must be possible to connect the motor's own temperature monitor (bimetallic strip or PTC
sensor).
This section contains further information on the operation of the pump in an explosive at-
mosphere. All personnel must read this section. This section applies to Ex approval pumps
only!
For use in explosive atmospheres, the pump must be marked as follows on the rating plate:
▪ "Ex" symbol for the relevant approval
▪ Ex classification
▪ Certification number (depending on the approval)
The certification number, if required by the approval, is printed on the rating plate.
The motor's design version corresponds to the following protection classes:
▪ Flameproof enclosure (ATEX)
▪ Explosionproof (FM)
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 tem-
perature controller (2‑circuit temperature monitoring).
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