ABB VD4 12 Installation And Service Instructions Manual

ABB VD4 12 Installation And Service Instructions Manual Manual pdf 41 page image

399. MaintenanceMaintenance operations are aimed at ensuringtrouble-free operation of the apparatus for thelongest possible time.In accordance with the specifications of the IEC61208 / DIN 31 051 Standards, the following op-erations must be carried out.Inspection: Determination of the actual con-ditionsServicing: Measures to maintain the speci-fied conditionsRepair: Measures to restore the speci-fied conditions.9.1. GeneralVacuum circuit-breakers are characterized bytheir simple and sturdy construction and long life.The operating mechanism requires minimummaintenance and the vacuum interrupters aremaintenance-free for their whole operating life.Vacuum interruption does not cause any harm-ful effects even in the presence of frequent tripsat the rated and short-circuit currents.The servicing interventions and their aim dependon environmental conditions, the sequence ofoperations and trips under short-circuit.NoteThe following Standards must be observed forall maintenance work:– the relevant specifications indicated in the“Standards and specifications” chapter;– the safety in the work place regulations givenin the “Putting into service and Operation” chap-ter;– the standards and specifications in the coun-try of installation.Maintenance work can only be performed bytrained personnel, observing all the safety regu-lations.It is recommended that ABB service personnelshould be called in, at least to check the serviceperformances and for repair work.While the work is in progress, turn the powersupply off and put the apparatus under safe con-ditions.Before carrying out any operations,check that the circuit-breaker is open,with the springs discharged and that itis not supplied (medium voltage circuitand auxiliary circuits).9.1.1. Operating lifeTypical life-expectancies for VD4 circuit-break-ers:– vacuum interrupters: up to 30,000 operations,depending on their type (see paragraph 7.2.3.);– actuator: up to 30,000 operations under nor-mal operating conditions, depending on the typeof circuit-breaker and with regular maintenance.9.2. Inspection and functional testing9.2.1. Interruption devices in general– Carry out regular inspections to verify the goodcondition of the interruption devices.– Inspection at fixed intervals can be waived ifthe switchgear is permanently monitored byqualified personnel.– Above all, the checks must include a visualinspection to find any contamination, traces ofcorrosion and electrical discharge phenomena.– When there are unusual operating conditions(including adverse climatic conditions) and/orin the case of environmental pollution (e.g.heavy contamination or an atmosphere withaggressive agents), inspection must be car-ried out more frequently.– Visual examination of the isolating contacts.Turning the contacts alternately is recom-mended, in order to keep the internal surfaceof the contact areas clean. The contact areasmust be cleaned if there are signs of over-heating (discoloured surface) (also see theparagraph on “Repairs”).– If any anomalous conditions are found, appro-priate servicing measures must be taken (seethe paragraph on “Servicing”).!