KSB Amarex N, Руководство по эксплуатации

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5 Installation at Site
29 of 72
Amarex N
Automatic operation of the pump set in a tank requires the use of level control
equipment.
Observe the minimum fluid level.
(
ð
Section 6.2.4.2, Page 36)
5.4.1.3 Frequency inverter operation
DANGER
Operation outside the permitted frequency range
Explosion hazard!
▷ Never operate an explosion-proof pump set outside the specified range.
NOTE
The motors can also be operated on frequency inverters. Make sure to observe the
design data of the motor in this case. To prevent an inadmissible heat build-up in
the motor, motors operated on frequency inverters must always be equipped with
bimetal switches in the stator. When reaching the temperature limit, the motor
must be cut out by means of a tripping unit for the equipment to comply with the
ATEX 100a Directive. This tripping unit shall be connected to the measuring points
provided to ensure the temperature class stipulated for the plant is observed.
DANGER
Incorrect setting of frequency inverter current limit
Explosion hazard!
▷ Set the current limit to max. 1.2 times the rated current indicated on the name
plate.
Selection
When selecting a frequency inverter, check the following details:
▪ Data provided by the manufacturer
▪
Electrical data of the pump set, particularly the rated current
Start-up
▪ Ensure short start ramps (maximum 5 seconds).
▪
Only start speed-controlled operation after 2 minutes at the earliest.
Pump start-up with long start ramps and low frequency may cause clogging.
Operation
Observe the following limits when operating the pump set via frequency inverter:
▪ Only utilise up to 95 % of the motor rating P
2
indicated on the name plate.
▪
Frequency range 30-50 Hz
Electromagnetic
compatibility
Frequency inverter operation produces RFI emissions whose level varies depending on
the inverter used (type, interference suppression, make). To prevent the drive system,
consisting of a submersible motor and a frequency inverter, from exceeding the limits
stipulated in EN 50081 always observe the EMC information provided by the inverter
manufacturer. If the inverter manufacturer recommends using a shielded power
cable, make sure to use a pump set with a shielded power cable.
Interference immunity
The pump set generally meets the interference immunity requirements to EN 50082.
For monitoring the sensors installed the operator must ensure sufficient interference
immunity by appropriately selecting and laying the cables in the plant. No
modifications are required on the power/control cable of the pump set. Suitable
analysing devices must be selected. To monitor the leakage sensor inside the motor,
it is recommended to use a special relay available from KSB.