Electrical Connections; General Safety Precautions; Wiring; Ground Connection - Zenit UNIQA Anleitung

First installation manual – Translation of original instructions

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.
•
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.
•
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 nameplate 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:
S1 continuously running: ± 5%
S3 intermittent running: ±10%
•
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 nameplate.
•
Make sure that the thermal protection devices are properly connected: apart from leading to forfeiture of warranty cover, failure to connect the
EN
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 ends of the electrical cables have not be exposed to damp and/or immersed in water.
•
The cable's free terminals must be connected to a regulation 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.
•
In case of use with a variable frequency drive, use screened cables compliant with the relevant regulations.
The ends of the power supply cable must be connected to an electric panel certified for use in potentially explosive atmosphe-
res 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.
On -Ex pumps, make sure that an external earth conductor (yellow and green, with cross section at least of 4 mm²) is con-
nected to the external earth terminal on the pump using a secure cable clamp. Clean the surface of the externa earth connec-
tion 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.
-Ex models in DRY version are equipped with a bimetallic thermal protector with a nominal switching temperature NST=120°C
inside the lower bearing support to shut down the power supply and prevent the surface overheating in case of malfunction in
the cooling system. The thermal protector in the lower bearing support and those in the winding stator are connected in series
(Fig 22). On customer request, A PTC thermistor or PT100 sensor could be installed as alternative and/or with independent
terminals.
warning!
For non-standard electrical configurations, please refers to the specific documentation supplied with the unit.
It is mandatory that the user connect thermal protectors
with a tripping unit in the control panel set in a way to avoid
the automatic restart of the equipment. The pump must be
exclusively restarted manually by 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 (Fig. 17) 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
40
S S1
17
better together
S2 S3
18