Page 22 - MINISTACK Fuse Switch Disconnector Unit

Operating & Maintenance

Operation Maintenance Suggested Specification
The following information details the It is recommended that a six monthly All fuse switch stacks are to be rated
correct operating procedure for the inspection and test be made using the at either 50kA or 63kA and conform
standard equipment supplied on a following procedures: to the requirements of AS3439.1.
Ministack assembly. Fuse switch disconnector units shall
Note: If the equipment is operating
in a dusty or corrosive atmosphere, be rated at 660V AC and 250V DC.
Fuse Switches
this inspection should be made more All fuse switch stacks shall be
(a) Withdraw the sliding operating frequently and appropriate remedial provided with an integral fully
handle. action taken. shrouded riser busbar system,
(b) Move the handle upwards to the encapsulated within the DMC
‘ON’ position or downwards to Fuse Switches moulding of the fuse switch
the ‘OFF’ position. Operate the (a) Turn switch off. disconnector units. The line side
switch handle firmly to its full limit. connection from the switch to the
(b) Remove moving carrier from switch.
riser busbar system, shall be of a
Carrier Removal/Fuse Replacement (c) Visually check carrier contact blades plug in type.
for discolouration and arcing
All combination fuse switch units
damage, replace if excessive.
shall be fitted with ASTA20 certified
(d) Clean switch blades if necessary LV HRC fuse links.
and regrease.
Fuse switch stacks are to be
(e) Ensure all fuse connections are ALSTOM Ministacks or equivalents.
tight to following torque values : The fitted fuse links are to be GEC,
1/200A – 8-11 Nm EE or GE Red Spot or equivalents.
4/630/800A – 12-15 Nm All future fuse switch disconnector
spaces shall be supplied to allow
fitting of future switch units at a later
date without supply interruptions.

Note: The application of grease should
To remove the fuse carrier, open only be made on the lead-in chamfer
the front door, withdraw operating of the blades. The amount used should
handle and apply sufficient upward not be excessive. Shell LGP1 or Darina
pressure to the operating handle R2 grease must be used. DO NOT
to release the interlock while at the use vaseline or petroleum jelly.
same time pulling the fuse carrier Transport
outwards in a horizontal direction.
DO NOT depress the door safety Switch must be transported in
interlock during this operation. ‘ON’ position.

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