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The excess power protection arrangement is to be seen
here as additional monitoring. The power limitation of the
converter is set at the highest to 3 x the motor current.
10.5.5. Potential equalization
It is possible for equalization flows (stray or leakage cur-
rents) to flow intermittently or continuously in electrically
conducting plants or components. For this purpose it is
necessary to install a potential equalization in accordan-
ce with EN 60079-14. On the ex-protected HOMA sub-
mersible motors there are installed an outer connection
of min 4 mm2 to max. 6 mm2 for creating a potential
equalization. Further application information for this is to
be taken from the applicable country explosion protection
ordinances.
Installation information for the mechanical part
Caution! The fluid cover of the pump hydraulic must
be monitored by a leveling control!
10.5.6. Danger due to spark generation
Mechanically generated sparks can ignite flammable ga-
ses and condensates. According to EN 1127-1 Para. 6.4.4,
sparks must also be excluded for category 2 in normal
operation. In normal operation no spark generation is pos-
sible due to fluid covering (medium covering of the pump
hydraulic). The ingress or suction of foreign bodies (sto-
nes, pieces of metal, etc) through the suction nozzles into
the pump hydraulic is not possible in an expected case
of malfunction in which the enclosure fails as the pump
cannot suck up pumping medium nor its containing solids.
In the ventilated shaft, the explosion-protected submer-
sible motor pumps are drained via a drain system with
two guide tubes of galvanized steel, between their guide
claws of grey cast iron that guide it into the automatic cou-
pling arrangement. The guide velocity, with max 0.1 m/s
(10 cm/s) is so low that no sparks can be generated even
in the most disadvantaged conditions. In the first installati-
on, the guide claws of the drain arrangement should be lu-
bricated with ball bearing grease in order to suppress heat
and spark generation in the most disadvantaged case.
10.5.7. Danger due to hot surfaces
Hot surfaces can only occur in the case of an expected
malfunction. Here an operational heating to a maximum of
70% of the temperature classification limit T4 (135°C) can
be expected. However. If, in the case of a malfunction,
the temperature limit is reached, then the temperature
monitoring of the electric motor, which is connected with
the mechanical part (pump) by means of a common shaft
will force the whole unit to be separated from the grid.
Caution! As a preventive measure for the occurrence
of temperatures at the mechanical part of the sub-
mersible motor above the temperature classification
T4, a level safety system with a safety-integrity level
SIL2 is to be installed and checked. (see Chap. 4). The
safety system is to be programmed and switched
such that an operation of the unit is only permitted
with a prescribed medium cover of the pump hydrau-
lic of a minimum of 0.2 m.
All manuals and user guides at all-guides.com
10.5.8. Danger due to static charge
Under certain circumstances, electrostatic charge can
release flammable discharges. The HOMA explosion-pro-
tected submersible pumps contain no rechargeable insu-
lated conducting components such as plastics. In addition,
there is an external connection for generating the poten-
tial equalization which must be installed by the user. If
further components or elements installed in the ex-zone,
then the user is required as the most important measure
according to EN1127-1Para 6.4.7, to undertake the linking
and grounding of all conducting parts and substances.
10.6. Start-up
If all the required and previously described installations,
safety and process instructions are carried out, then the
pump system must be taken into operation by an electri-
cal technician and tested as follows:
10.7. Repair, servicing and interventions into
explosion-protected submersible motors
For repairs or interventions, first observe the safety de-
terminations, especially those relevant for ex-protective
aspects as described above.
Caution! In order to ensure that the pump system ac-
tually works as described in Para 2.2.3 of the applica-
tion conditions, a measurement of the power
consumption (KW)) is to be carried out and checked
with the information in the table in Appendix 1. As the
pump first pumps into an empty pipe system, a higher
power consumption will be set at the start of the
pumping, depending on the height and length. Let the
pump continue until a final and stable power
consumption is set.
If the power consumption is within the given pow-
er limits of the motor then the explosion-protected
submersible motor pump can be finally taken into
service. If it is then seen that the power consump-
tion is outside of the given power limits of the mo-
tor, then the explosion-protected submersible motor
pump must not be taken into service. In this case the
pipe characteristic of the installed pressure pipe is to
be calculated and determined. The actual operating
point of the plant can be determined with the use of
the in-house HOMA HOPSEL pump design program.
For safe and ex-conformity start-up contact an em-
ployee of the HOMA Company!
EngliSH | 55
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