ABB V-Contact VSC Series Installation And Service Instructions Manual page 17

5.6. Assembly and making the connections
5.6.1. Fixed contactors
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Introduction
Before carrying out any installation operations:
• Test all the power terminals to check that they
are not supplied with voltage. Only use high
voltage testing equipment approved for
checking the voltage on the power terminals.
Do not attempt to measure the high volt-
age (above 600 volt) with a volt-ohm/meter.
• Check all the control and secondary circuit
terminals with a voltmeter to ensure that all
the control and secondary input voltage
sources have been turned off.
• Connect the safety earthing to the power ter-
minals after having turned the power supply
to the system off and before working on the
apparatus.
• Carry out all the operations for turning off the
voltage and earthing according to the estab-
lished safety procedures.
Power circuit
General precautions
– Check that the connections of the fixed
contactor or the isolating contacts of the with-
drawable contactor are clean and free of any
deformation caused by shocks received dur-
ing transport or storage in the warehouse.
– Select the cross-section of the conductors
according to the service current and the short-
circuit current of the installation.
WARNING
Dangerous voltages. Risk of death, serious injury to people, damage to
the apparatus or other objects.
Togliere l'alimentazione, mettere a terra e in sicurezza tutte le fonti di potenza
e di tensione di controllo prima di iniziare i lavori su questo o qualsiasi
apparecchio elettrico. L'installazione deve essere effettuata solo da personale
qualificato.
– Prepare special pole insulators, near the ter-
minals of the contactor, sized according to
the electrodynamic forces deriving from the
short-circuit current of the installation and
avoid stressing the connections laterally.
Surface treatment of the connections
The connections can either be made of bare
copper or bare aluminium. In any case, it is al-
ways advisable to silver-plate the contact sur-
faces. The surface treatment must have a con-
stant and even thickness.
Assembly procedures for fixed contactors
– Check that the contact surfaces of the con-
nections are flat, and are free of any burrs,
traces of oxidation or deformation caused by
drilling or impacts received.
– Carry out the operations indicated on the con-
tact surface of the conductor (silver-plated
copper):
- clean with a rough dry cloth
- only in the case of obstinate traces of oxi-
dation, clean with a very fine grain emery
cloth taking care not to remove the surface
layer
- if necessary, restore the surface treatment
(consult ABB)
- put the connections in contact with the
contactor terminals, taking care to avoid
mechanical stresses produced, for example,
by the conductor busbars on the terminals
themselves.
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