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Maintenance
9.2 Inspection and maintenance
9.2.8
Maintenance
9.2.8.1
Explosion protection for machines with flameproof enclosure
For explosion-proof machines with type of protection flameproof enclosure according to IEC/
EN 60079–0 and IEC/EN 60079–1, follow these instructions:
• Machined bearing and fitting surfaces on the following components must not be reworked
or painted:
– Stator frame
– End shields, bearing cover
– Motor shaft
– Gland plate
– Lower part of terminal box, terminal box cover
– Gland plates for additional terminal boxes, where present
• Keep the surfaces clean. Protect the surfaces against corrosion by applying a thin coating of
grease. It is not permissible that any seals are fitted between the surfaces that guarantee that
flame is not transmitted.
• The threaded holes on the following components must not be reworked or painted:
– Threaded holes for cable entry in the terminal box
– Threaded holes for cable penetrations and sealing plugs in the gland plate
9.2.8.2
Insulation resistance and polarization index
Measuring the insulation resistance and polarization index (PI) provides information on the
condition of the machine. It is therefore important to check the insulation resistance and the
polarization index at the following times:
• Before starting up a machine for the first time
• After an extended period in storage or downtime
• Within the scope of maintenance work
The following information is provided regarding the state of the winding insulation:
• Is the winding head insulation conductively contaminated?
• Has the winding insulation absorbed moisture?
From this, you can determine whether the machine needs commissioning or any necessary
measures such as cleaning and/or drying the winding:
• Can the machine be put into operation?
• Must the windings be cleaned or dried?
Detailed information on testing and the limit values can be found here:
"Testing the insulation resistance and polarization index" (Page 64)
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1MB..5/6 shaft height 71 ... 355
Operating Instructions, 11/2023, A5E52779956A
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