ABB MNS-MCC, Инструкция по установке, эксплуатации и обслуживанию

Страница: 42 / 52

42
M N S - MCC
LO W VO LTAG E M OTO R CO N T R O L C EN T ER
When the unit door is closed, another slotted hole
in the bottom of the shaft engages a Spring-loaded
lever (Item 17 of Fig. 42) at the bottom center of the
unit. This lever is connected to the interlock wheel
on the bottom of the unit. This wheel is lifted when
the operating handle is rotated to the MOVE
position, allowing the unit to be moved in or out of
the MCC cubicle.
As the unit moves, the wheel will drop into one of
two recesses in the steel shelf that supports the
unit in the MCC section, locking the unit in place.
These two recesses in the bottom plate accept the
wheel in the ENGAGED and the ISOLATED unit
positions, locking the unit in place and preventing
it from moving unless the operating handle is again
placed in the MOVE position.
Adjust the shaft as necessary so that it engages the
spring-loaded wheel lever on the unit chassis,
allowing smooth closure of the door and providing
for correct and reliable operation of the unit
interlock mechanism. When properly adjusted, the
operating handle will reliably spring back to the
OFF position after being moved to the ENGAGED
and ISOLATED positions.
Inspect units
Recommended Interval: Perform prior to first
installation and periodically according to your local
maintenance schedule:
• Visually inspect the contacts for damage. Look
for excessive wear or damage (e.g. worn silver or
tin layer, signs of excessive heat, etc.) on all
contact surfaces, including distribution bars,
withdrawable units, power cable connection unit,
etc. If you are unsure of the contact condition,
measure the contact clearance with a slide or
standard gauge. The clearance must be 4.7 mm
+0.05/-0.2 (0.18 in +.002/-0.001).
• Test for contact float. The power contacts are
contained in a black plastic housing for incoming
and outgoing power connections. These contacts
must move freely from side to side, indicating
that they are properly installed. Verify that
contacts are movable and properly snapped into
position in the withdrawable unit rear wall or
contact apparatus housing.
• Using the proper tool for each connection, verify
the tightness of all control and power terminals
within the units.
• Be sure that the contacts are properly greased. If
they appear dry, use a brush to apply the
appropriate amount of contact grease, e.g. Fuchs
CHEMPLEX® 825. Each unit will require
approximately 3.5g of lubricant to grease both
the incoming and outgoing contacts.
If you detect contact damage, we recommend
replacing the entire withdrawable unit chassis or
the entire contact system. Contact your ABB
representative for assistance with repair or
replacement.
Exterior metal damage repair
Any scratches or damage to the surface of the
vertical sections must be repaired in order to avoid
oxidation, which can reduce the life of the
equipment.
For small areas of damage, ABB supplied touch-up
paint kits are available. To obtain a kit, contact your
ABB representative.
Maintenance schedule
Warning:
Defects or deficiencies in any
electrical equipment should be remedied
immediately. If immediate repair is not
possible, Lockout/Tagout the equipment
until after repairs have been made, or
replace the withdrawable unit.
It is highly recommended that you establish a
periodic maintenance program for the MCC. The
frequency of maintenance activities depends on
equipment usage and the operating environment.
Arc flash protection
The National Fire Protection Association (NFPA
70E) has established the flash protection marking
requirement1 that applies to personnel who install,
maintain, or repair electrical systems.