For Transformer Manufacturer - c.a.p.t. AT Serie Manual Del Instrucciones

ELECTRICAL CONNECTIONS OF THE CONTROL DEVICE (INDIRECT TRANSMISSION)
When the control device with the indirect transmission is equipped with, not only the mechanic locking
mechanism, but also with micro-switches, the terminal board must be connected by following the
procedures shown in the enclosed drawings of the instruction booklet. It is absolutely necessary to connect
the locking mechanism, specially if the hand-wheel makes more then 1 rotation to change a single position.
If they are available, connect the micro-switches for the remote control of the positions and manoeuvres.
MAINTENANCE
During the maintenance of the transformer or at least once a year is recommended (although not a
requirement), especially if the switch remained in the same position, with the transformer de-energised,
to carry at least 10 operations across the range of taps. Such operation is recommended for a longer life
of the switch. In this way, you avoid the formation of a thin film in correspondence of the active part of the
fixed and moving contacts, due to oxidation and impurities dispersed in the oil.
It also protects against the formation of "pyrolitic" carbon formation that can occur when the contacts
remain on a position for long periods with a consequent increase of the contact resistance. Before and
after this self-cleaning of the contacts may be useful to check the efficiency of the switch by means of a
resistance measurement (mΩ) of the phases.
EXTRACTION OF THE TRANSFORMER FROM THE TANK
DIRECT DRIVE:
It is not necessary to remove the tap changer from the cover but only lowering the oil level below the top
level of the tank.
In case of tap changer drive assembled on top of tank wall, lowering the oil level below the level of drive.
INDIRECT TRANSMISSION:
It is not necessary to disconnect the tap changer, but you only need to lower the oil-level to below the
line of the indirect transmission gear connection or of the control box mounted on the lid, or affixed
on either the top or the bottom section of the transformer's tank side.
• Tap changer is not a finish product;
• It is submitted to successive handling and drying process;
• Perform a correct installation;
• Keep in dried and clean environment;
• Handle with care;
• Bakelite, and polyamide components are delicate and fragile materials;
• Before and after drying process lubricate the contacts with dielectric oil;
• Immediately after drying process do not operate the tap changer when it is yet hot;
• It is also indispensable check the tap changer screws, bolts and nuts, including the elastic pins
of tap changer;
• Connecting cables between windings and tap changer must not force or press on tap changer, not
even during fixing (screwing) procedure after drying oven treatment.
• Tap changer assembling must be done following a correct procedure, checking intermediate and
gear support connection do not cause any abnormal force or pressure on tap changer.
FOR TRANSFORMER MANUFACTURE
WARNING
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