KSB Amarex KRT Installation & Operating Manual page 28

Selection
Setting
Start-up
Operation
Electromagnetic
compatibility
Interference immunity
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5 Installation at Site
5.4.1.2 Level control
DANGER
Pump set running dry
Explosion hazard!
▷ Never allow an explosion-proof pump set to run dry!
CAUTION
Fluid level below the specified minimum
Damage to the pump set by cavitation!
▷ Never allow the fluid level to drop below the specified minimum.
Automatic operation of the pump set in a tank requires the use of level control
equipment.
Observe the minimum fluid level. (⇨ Section 6.2.4.2 Page 35)
5.4.1.3 Operation on a frequency inverter
The pump set is suitable for operation on a frequency inverter as per IEC 60034-17.
DANGER
Operation outside the permitted frequency range
Explosion hazard!
▷ Never operate an explosion-proof pump set outside the specified range.
DANGER
Incorrect selection and setting of the frequency inverter
Explosion hazard!
▷ Observe the following information on selecting and setting a frequency
inverter.
When selecting a frequency inverter, check the following details:
▪ Data provided by the manufacturer
▪ Electrical data of the pump set, particularly the rated current
▪ Only voltage source inverters (VSI) with pulse width modulation (PWM) and
carrier frequencies between 1 and 16 kHz are suitable.
Observe the following instructions for setting a frequency inverter:
▪ Set the current limit to max. 1.2 times the rated current indicated on the name
plate.
▪ Ensure short start ramps (maximum 5 seconds).
▪ Only start variable speed control after 2 minutes at the earliest.
Pump start-up with long start ramps and low frequency may cause clogging.
Observe the following limits when operating the pump set on a frequency inverter:
▪ Only utilise up to 95 % of the motor rating P
▪ Frequency range 25 - 50 Hz
Operation on a frequency inverter produces interference 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
powercable.
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
Amarex KRT
indicated on the name plate.
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