IMP Pumps ECL - Handbuch (Seite 18)

-18-
GB
control checks.
- Installation, repairs, and maintenance of
pumps must be carried out at the time the
pump is not operational as per regulations.
- Special care must be taken when exposed
to harmful medium. In special circum-
stances, decontamination of all external
surfaces of the pump is necessary.
- On completion of repairs, maintenance
works, and other interventions on the
pump, parts that are important for safety
and protection, must be reattached into
their original positions to fulfil their function.
- Restarting the pump must be carried out
according to the same instructions as for
the initial start-up of the pump in the sys-
tem.
- Changes and modifications to the pump
are permitted with the consent of the
manufacturer and authorised maintenance
service and with the use of original parts.
With any other repairs and maintenance
of the pump, the manufacturer bears no
responsibility for the incorrect operation of
the pump.
- Pump operation is not allowed if the manu-
facturer’s instructions are disregarded, or if
the pump is operated contrary to the work-
ing conditions and characteristics as pre-
scribed by the manufacturer on the display
plates.
3. p
uMp descriptiOn
A) General, systems controlled by
frequency converters
Frequency converters are used for control-
ling the number of electric motor revolutions
in modern alternating drives. Changes in the
amplitude and frequency of the electric sup-
ply are used for controlling a highly efficient
induction electric motor. The frequency con-
verter or inverter is composed of the IGBT
module with three pairs of energy clutches
that can compose the electric motor coil on a
positive or negative pole of direct power sup-
ply. At the entrance of the frequency convert-
er, the 50 Hz network voltage stabilises with a
diode bridge and filters in the capacitor circuit.
The IGBT module converts the power supply
of the circuit from a pulse width modulation
into a symmetrical three-phase AC voltage
amplitude and frequency. The change relation
of the voltage amplitude and the U/f frequency
is linear or parabolic.
A 16-bit microcontroller constitutes the basis
of control on the frequency converter.
A special connection controls the circuit volt-
age and through the microcontroller regulates
the undervoltage (reduced network voltage)
or the overvoltage (increased network volt-
age) protection (overvoltage load in the circuit
despite the increased speed in braking).
Controlling the converter operation or chang-
ing parameters is achieved through serial
communication. The other possibility of con-
trol is achieved through externally guided
contacts and signals. Changing the frequency
or the revolution speed of the electric motor is
possible with a potentiometer, as control with
a voltage signal 0-10 V, and a current signal
0-20 mA or 4-20 mA can be implemented
through the same entrances.
Basic commands are entered through the
keys RESET, START, STOP, FUNC…
A special connection controls the circuit cur-
rent towards the electric motor and starts the
current protection (overload, short-circuit, im-
proper earthing) through the microcontroller.
A signal relay that signals with contacts the
state of the running electric motor (regard-
less of speed) and the occurrence of alarms
(errors) is connected to one of the digital
exits of the microcontroller.
B) Pump description and components
Electronically regulated ECL pumps are
composed of a centrifugal pump of desired
power and an electronic regulator. The
electronic regulator is placed separately from
the pump.
The electronic regulator is composed of
the frequency converter and the pressure
difference meter.
The technical details of individual pumps,
the pump execution, details, choice, and
purpose of use are given in the ECL pumps
catalogue.