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Preventive Maintainance
3ADW000195R0501 DCS800 Service Manual e e
Annual preventive maintenance
The following actions have to take place:
Check the cooling fans of units D1 to D7.
The lifetime of the cooling fan is about 30,000 to 45,000 hours depending on
the converter type. The actual lifetime depends on the usage of the DCS and
the ambient temperature.
Fan failure can be predicted by means of increasing noise from its bearings
and a gradual rise of the heatsink temperature. If the DCS operates in a critical
part of the process it is recommended to replace the fan once the above
mentioned symptoms appear.
Check the cooling air pressure switch of units D6 and D7.
Cooling air pressure switch
Actions:
Make sure electrical safety is performed.
Open the module's door and hold it in position to prevent any movement.
Repeat it with the cabinet’s door.
Start the drive.
The air pressure switch is ok when the converter is switched off by F527
ConvFanAck - see ConvFanAck (10.30). Crosscheck this result with the
module’s door closed.
Attention:
Do not reach into the fan. Negligence to this warning can cause injury.
Check for tightness of heatsink terminals of units D7.
The thyristors together with the heatsinks are stacked. Every single thyristor is
connected to the DC+ and DC- busbars via flexible copper busbars. These
busbars consist of 10 layers of pre-shaped sheet copper. This construction is
able to compensate for small changes in length caused by temperature rise
when current is flowing. The screw fixings between heatsink and flexible
copper busbar have to withstand different types of mechanical stress.
Therefore each fixing needs to be checked for correct torque.
Actions:
Make sure all supply voltages are switched off, most important the supply
for the power part (armature), for the drive electronics (SDCS-POW-4), for
the converter fan and for other auxiliaries!
Open the cabinet’s and module’s door; if needed secure them.
Set a latching torque spanner to 25 Nm (18 lb-ft). A 17 mm nut is needed
too.
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