ABB UniGear ZS1 - Page 123

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Earthing switches
Cleaning the kinematics to prevent faults on the
signalling contacts
• Carry out a visual inspection of the
kinematics and check for any presence of
dirt, humidity and signs of corrosion on the
moving parts.
• Manually check correct changeover of the
earthing switch signalling contacts (Figure
195).
• Remove any deposits of dust using a dry
cloth that does not leave any deposits on the
treated surfaces (do not use woollen cloths).
• If necessary, grease the mechanical moving
parts by applying a thin layer of mechanical
grease for moving parts.
• Carry out a visual inspection on the toothed
wheel and pinion 2 (Figure 194) and check any
presence of dirt, humidity and signs of
corrosion on the moving parts.
Instrument transformers
Cleaning and checking of the current
transformers
• Open the cable compartment door.
• Remove the circuit-breaker plate (Figure 196)
to get larger access.
• Visually check the connections of the current
transformers.
• Using a dynamometric spanner, check the
tightness of all the screws. Refer to the table
in "6.3 Assembly of the switchgear panels"
for the tightening values.
Cleaning and checking of the voltage
transformers and anti-ferroresonance circuit.
Fixed version voltage transformers:
• Open the cable compartment door.
• Remove the circuit-breaker plate (Figure 196)
to get larger access.
• Visually check the voltage transformer
connections.
• Using a dynamometric spanner check
tightness of all the screws. Refer to the table
in (chapter 6.3) for the tightening values.
• Carry out a visual inspection of the
transformers and check for any presence of
dirt.
• Remove any deposits of dust using a dry
cloth that does not leave any deposits on the
treated surfaces (do not use woollen cloths).
Voltage transformers in removable version:
• Open the cable compartment door.
• Manually withdraw the VT truck.
• Carry out a visual inspection of the
transformers and check for any presence of
dirt.
• Remove any deposits of dust using a dry
cloth that does not leave any deposits on the
treated surfaces (do not use woollen cloths).
Voltage transformers in withdrawable version:
• Open the cable compartment door.
• Manually withdraw the VT truck.
• Carry out a visual inspection of the
transformers and check for any presence of
dirt.
• Remove any deposits of dust using a dry
cloth that does not leave any deposits on the
treated surfaces (do not use woollen cloths).
Cleaning and checking the anti-ferroresonance
circuit
• Open the miniature circuit-breakers 1 (Figure
189) positioned inside the low voltage
compartment to remove the auxiliary power
supply to the panel.
• Carry out a visual inspection on the anti-
ferroresonance resistors and check for any
presence of dirt.
• Manually check correct insertion of the
cabling
Cleaning and checking of the fuses
• With the VT truck withdrawn, manually hook
up the fuses contained in the resin tube of
the voltage transformers.
• Carry out a visual inspection on the fuses and
check for any presence of dirt.
• Remove any deposits of dust using a dry
cloth that does not leave any deposits on the
treated surfaces (do not use woollen cloths).
Maintenance in circuit-breaker compartment
Lubrication of the isolating contacts:
• Remove any deposits of dust using a dry
cloth that does not leave any deposits on the
treated surfaces (do not use woollen cloths).
• If necessary, grease the mechanical moving
parts by applying a thin layer of mechanical
grease for moving parts.
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9. Maintenance