Homa GRP16 Betriebsanleitung Seite 67

From motor sizes AM303 there is built in as standard and in accordance with previously described protective
measures, each a conductivity probe and a magnetic buoyancy floating switch (only for vertical operation) in the
oil bearings. A temperature excess above 130°C (T4) at the seals as well as at the housing surface is
safeguarded according to the measures mentions in Section 4.3!
Caution
In ex intrinsically safe circuits the instrument lines are marked in blue.
Operating off the grid
It is also absolutely necessary that for operating off the grid to install with thermally delayed excess power triggers
also temperature limiters with the strand designations T1 and T2 to the controls in accordance with the connection
diagram!
Frequency converter operation
For frequency converter operation it is absolutely necessary to install an arrangement for direct temperature
monitoring. This consists of a PT thermistor built into the coil according to DIN 44 082 and a function-tested
triggering device according to RL 94/9/EG. 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.
Potential equalization
It is possible for equalization flows (stray or leakage currents) to flow intermittently or continuously in electrically
conducting plants or components. For this purpose it is necessary to install a potential equalization in accordance
with EN 60079-14. On the ex-protected HOMA submersible motors there are installed an outer connection of min
2 2
4 mm to max. 6 mm 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!
Danger due to spark generation
Mechanically generated sparks can ignite flammable gases 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 possible due to fluid covering (medium covering of the pump hydraulic). The ingress or suction of foreign bodies
(stones, 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 submersible 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
coupling 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 installation, the guide claws of the drain arrangement
should be lubricated with ball bearing grease in order to suppress heat and spark generation in the most
disadvantaged case.
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 submersible 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 hydraulic of a minimum of 0.2 m.
Danger due to static charge
Under certain circumstances, electrostatic charge can release flammable discharges. The HOMA explosion-
protected submersible pumps contain no rechargeable insulated conducting components such as plastics. In
addition, there is an external connection for generating the potential 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.
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