Zenit UNIQA Serie Bedienungsanleitung Seite 45

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5. ELECTRICAL CONNECTIONS
5.1 General safety precautions
All the procedures involved in connecting the unit to the electrical mains must be carried out by skilled staff in accordance with
the relevant legal requirements: incorrect electrical connections may cause fires and an electrocution hazard, or the risk of da-
mage to the product.
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Before carrying out any operation, make sure that the pump and electrical panel are disconnected from the electrical mains and cannot be
accidentally powered up.
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Check that the unused conductors are properly insulated and fixed in the electrical panel. .
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Before installation, make sure that the power supply line voltage and frequency are as stated on the nameplate and that the power absorption
of the pump is below the maximum current the system is able to deliver.
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The maximum voltage variation allowed for rated value is:
S1 continuously running: ± 5%
S3 intermittent running: ±10%
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Voltage imbalance between phases: max 2%
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The fuses and protective cut-outs must be of suitable rating for the system's characteristics.
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Protect the pump motor using an overload cut-out suitable for the electrical data provided on the nameplate.
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Make sure that the thermal protection devices are properly connected: apart from leading to forfeiture of warranty cover, failure to connect the
thermal protection may constitute a hazard.
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The electrical operation and safety of ZENIT electric pumps are guaranteed for the configuration supplied by the manufacturer: any changes
(e.g. addition of extra lengths of cable to the original power lead) may cause a deterioration in the pump's characteristics.
Before installation and the first startup, make sure that the electrical cables are not damaged in any way to avoid short circuit.
5.2 Wiring
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Make sure that the ends of the electrical cables have not be exposed to damp and/or immersed in water.
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The cable's free terminals must be connected to a regulation control panel with a degree of insulation suitable for the installation environment.
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If the cable is damaged, do not replace it; contact Zenit or an Authorised Service Centre.
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Do not underestimate the problems caused by voltage drops.
Secure and mechanically protect the electric cables so that they cannot be twisted, torn and/or crushed.
The ends of the power supply cable must be connected to an electric panel certified for use in potentially explosive atmospheres
if it is installed in a hazardous area
5.3 Operation by variable frequency drive (VFD)
The three-phase motors may also be powered by a "PWM (Pulse Width Modulation) – Constant Torque (U/F=constant)" frequency inverter. Set
the frequency converter U/f ratio according to the motor data.
Ex models may never, without exception, be operated using a frequency greater than the rated value indicated on the namepla-
te as this may cause motor overload. The lowest frequency must be set so that it does not fall below 30 Hz.
Make sure that the rated current specified on the nameplate is not exceeded after starting the motors.
The maximum number of starts according to the technical data sheet of the motor must not be exceeded.
The thermal protection of the motor must be connected.
Use input and output filters on the frequency converter. Please refer to the data sheet of the model used.
5.4 Ground connection (Fig. 14)
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Make sure that the ground system and differential security breaker are present and in good working order.
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Check that the ground conductor is about 150 mm longer than the other conductors so that it will be the last to become disconnected from the
panel in the event of accidental tugs.
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The predisposition for the connection of the external earth conductor accepts cables with a cross-sectional area of at least 4 mm².
Do not connect the ground wire to a gas pipe, water
pipe, lightening rod, or telephone ground wire.
Improper grounding could cause electrical shock.
On -Ex pumps, make sure that an external earth con-
ductor (yellow and green, with cross section at least
of 4 mm²) is connected to the external earth terminal
on the pump using a secure cable clamp. Clean the
surface of the external earth connection and mount
the cable clamp.
Safety, Installation and Operations Manual – Translation of original instructions
14
EN
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