YASKAWA MOTOWELD-T300D, Инструкция по эксплуатации, Страница: 42 / 70

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■
Quarterly to Semiannual Inspection Items
Perform the following:
• Removal of dust and dirt
Remove dust and dirt by spraying dry compressed air. Carefully clean spaces
between the transformer and reactor windings, and semiconductors.
•
Inspection of electric connecting sections
Check that the bolts are firmly tightened and rust or the like does not deteriorate the
contacts in the connecting sections with the external wiring such as input/output
terminals or with the internal wiring. Retighten the bolts if necessary or use a file to
remove rust, if any, so that the metallic faces contact with each other.
• Inspection of ground line
Confirm that the case is grounded properly.
■ Annual Overall and Repair
Carry out the integrated repair such as replacement of defective components, case repair,
and reinforcement of insulation deteriorated parts. Insulation resistance must be 1 M
Ω
or more between the control unit circuit and the case; if it is less than 1 M
Ω
, the insulation
of the deteriorated part must be repaired.
■
Guideline for Service Lifetime and Replacement of Components
Used
The welder is composed of many components. Unless all these components operate
normally, the welder cannot utilize its essential functions. Therefore, it is absolutely
necessary to find any sign leading to a failure of a component or device as early as possible
according to the periodical inspection and take proper corrective action.
These components cannot be used continuously for ever. Even under normal operation
status, they are apt to have variation of the characteristics or malfunction after the life
elapses.
Therefore, it is recommended that the components be replaced periodically so that the
welder can operate at optimum performance.
Normally, refer to the following guideline of the component replacement when the welder
is used in the rated specifications (8 hours a day, 250 days a year). Especially, the
secondary side magnetic contactor has electric durability of 2 million times under rated
operations. In addition, when the insulation resistance between main contacts is
deteriorated to 100 M
Ω or less in the single unit, the welder may be hard to start.
•
Electrolytic capacitor : Approx. 5 years
•
Cooling fan: Approx. 5 years
•
Breakers, relays: Depends on how often they are used. It is recommended that they
be replaced approx. every 5 years.