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4. ELECTRICAL CONNECTIONS
4.1 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 damage to the product.
• Check that the unused conductors are properly insulated and fixed in the electrical panel. .
• Before installation, make sure that the power supply line voltage and frequency are as stated on the dataplate and that the power absorption of
the pump is below the maximum current the system is able to deliver.
• The maximum voltage variation allowed for rated value is ± 5%
• Voltage imbalance between phases: max 2%
• The fuses and protective cut-outs must be of suitable rating for the system's characteristics.
• Protect the pump motor using an overload cut-out suitable for the electrical data provided on the dataplate.
• 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.
• 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.
4.2 Wiring
• Make sure that the electrical cables have not be exposed to damp and/or immersed in water.
• The cable's free terminals must be connected to a control panel with a degree of insulation suitable for the installation environment.
• Secure the electric cables so that they cannot be twisted, torn and/or crushed.
• If the cable is damaged, do not replace it; contact Zenit or an Authorised Service Centre.
• Do not underestimate the problems caused by voltage drops.
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
4.3 Ground connection
• Make sure that the ground system and differential security breaker are present and in good working order.
• 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.
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 conductor (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 externa earth connection and
mount the cable clamp.
4.4 Thermal protection
The equipment is equipped with thermal protectors inside the stator windings to shut down the power supply in case of motor overheating.
The standard thermal protection consists of bimetal thermal protectors with nominal switching temperature NST=150°C; as option, bimetallic
protectors can be replaced by PTC thermistors or PT100 sensors.
The thermal protection cables are marked with a label stating "TP" = THERMAL PROTECTION and must be connected to the corresponding
terminals of the control panel.
The connection of the thermal protectors to a control panel is mandatory. The electric panel must be predisposed to guarantee
the shutdown of the motor when the thermal protection intervenes and to avoid the automatic start-up of the pump which must
only be started manually with the intervention of a technician after having fixed the causes of the anomaly.
4.5 Leakage detector
The electric pump can be equipped with a single-electrode leakage detector as an accessory to detect and signal the infiltration of water into the
oil chamber of the mechanical seals (the equipment grounding conductor is used as the return path for the conductive level limit detection).
In the case of detection, take out of service the pump and proceed with maintenance.
The signal cable is marked with a label with the letter S.
For installations with -Ex certified models, the connection to the electric control panel must be carried out by inserting in safe
area an Intrinsic Safety barrier with galvanic isolation.
Electrical safety data for intrinsically safe circuit:
Leakage detector
U
: 30V; I
: 120mA; P
i
i
C
: 0.3nF; L
i
Cable
C
: 200pF/m; L
c
In the case of detection (electric resistance in the water/oil mixture less than 30 kΩ) take out of service the pump and proceed
with maintenance.
: 1.3W
i
: ~ 0mH
i
: 1µH/m; L
/R
= 30µH/Ω
c
c
c
Safety, Installation and Operations Manual - Original instructions
EN
35
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