MarelliMotori MXB-E 180 Serie Manual De Instalación, Funcionamiento Y Mantenimiento página 39

The generator can also be connected according to a zig-zag pattern (required voltage 220 - 240 Volt at 50 Hz or
220-240 V at 60 Hz) and the single-stage load must be connected to clamps U1/T1 and V1/T2.
Powering of capacitive loads only
You can power capacitive symmetrical 3-phase loads (leading cos-phi 0) to a maximum power (in KVAR) equal
to 0.25 times the rated power (in KVA).
5.8 Commissioning
Before commissioning the machine you need to verify the insulation with a Megger tester at 500Vdc 1
minute after applying the voltage.
The minimum value of the insulation strength for a new winding equal to 100 MΩ is one of the main
requirements for the stator electric safety.
IF THEY HAVE ALREADY BEEN IN SERVICE OR HAVE REMAINED UNUSED FOR LONG PERIODS,
GENERATORS MUST NOT BE STARTED IF THE INSULATION RESISTANCE IS LOWER THAN 30 MΩ AT
THETEMPERATURE OF 20°C. Otherwise recondition the active parts.
NEVER START THE MACHINE IF THE POLARISATION INDEX IS LOWER THAN 1.5. (Chapter 5.2)
In order to avoid electrocution dangers, connect the windings to ground for a short time just after the
measurement.
BEFORE THE FIRST START-UP, PERFORM THE FOLLOWING CHECKS:
Mechanic checks
Check that:

Bolts of feet are properly tightened.

Coupling is correct.

The cooling air rate is high enough and no impurities are taken in.

The protection grids are properly installed.

The tightening torque of the coupling discs und SAE union are correct (for single-support alternators).
Electric checks
Check that:

The system is equipped with appropriate leakage protections, in accordance with the applicable law
provisions.

The connections to the terminal panel terminals have been performed properly (check that clamps are
properly tightened).

There are no reversed connections or short-circuits between the generator and any external switches.
You should remember that normally there are no protections against short-circuits between the
alternator and external switches
To prevent damages to the current transformers and to the generator, all the current transformers
installed on the generator must be connected to their load: should the current transformers in question
be unused, their secondary circuits must be short-circuited.
963857252_=
Zig-zag connection
LOAD
Fig. 8
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