41
I N S TA L L AT I O N , O P ER AT I O N S A N D M A I N T EN A N C E M A N UA L
3) To completely remove the unit from the MCC
cubicle, grasp the unit firmly and be ready to
accept its weight. Press down on the thumb-
operated safety stop to release it, and slide the
unit the remainder of the way out of the cubicle.
Units, especially the 18E and larger may require
two people to handle the weight safely, spring
loaded handles may be provided on the left and
right side of the unit for handling purposes.
TIP: If the unit is outside the section and placed on
a flat surface, the weight of the unit will depress
the interlock wheel on the bottom of the unit (Item
7 of Fig. 42). This may prevent the unit’s door from
opening or closing properly and may prevent the
unit from locking into position when reinserted in
the cubicle.
To avoid this problem, and to open the door while
the unit is out- side its cubicle, tilt the unit
backward slightly to allow the wheel, which is
spring loaded, to fully extend.
Insert a unit
The handle must be in the OFF position.
Do not use the pull handles to lift or carry the unit.
1) Insert the unit into the section, ensuring that it is
level with the floor. Push the unit in until it stops,
at which point it will engage the mechanical stop
on the left-hand side of the unit, preventing it
from falling out of the MCC cubicle.
2) Rotate the operating handle to the MOVE
position and push the unit until it reaches the
ISOLATED position, where it will stop. The handle
spring returns to the OFF position. The unit is
now locked in place. All power and control
electrical contacts remain disengaged in this
position and no part of the unit is energized or
connected to any external wiring, power or
control, line or load.
If the handle does not return to the OFF position,
see the Troubleshoot Withdrawable Unit Interlock
section of this manual.
3) Rotate the operating handle again to the MOVE
position and push firmly and sharply until the
unit reaches the ENGAGED position. You need to
generate some momentum when pushing to
overcome the friction as the power plugs
engage. The handle returns to the OFF position.
The unit is now fully ENGAGED and ready to
energize.
TIP: If the unit does not fully move into the
ENGAGED position, you may have to withdraw the
unit again to the ISOLATED position and repeat
step 3. Advance the unit sharply and firmly when
moving it into the ENGAGED position.
Ensure that the unit is fully engaged by pulling
sharply on the two pull handles. The unit should be
locked in place. If it moves, return the handle to the
MOVE position and withdraw the unit to the
ISOLATED position. Then follow the above
procedure to reinsert the unit to the ENGAGED
position. Test to ensure that it is locked in place.
4) You can now energize the unit by rotating the
handle to the ON position.
Troubleshoot withdrawable unit interlock
If the handle fails to spring back automatically to
the OFF position as the unit is moved from
WITHDRAWN to ISOLATED to ENAGED, (or in the
reverse order when being removed from the MCC
section) the connection between the locking wheel
on the bottom of the unit and the operating handle
mechanism is improperly adjusted.
To correct this problem, adjust the flat metal shaft
(Item 4 of Fig. 42) vertically oriented on the rear of
the withdrawable unit door, extending between the
operating mechanism and the bottom of the door.
Loosening the screw at the base of the operating
mechanism that holds the shaft in place. The
slotted hole in the shaft allows it to be adjusted
up and down slightly after loosening the screw.
Содержание MNS-MCC
Страница 2: ......
Страница 50: ...50 MNS MCC LOW VOLTAGE MOTOR CONTROL CENTER ...
Страница 51: ......
