PART- II
Stator lifting by EOT Cranes:-
In earlier days up to 210
/250 MW class the stator is being lifted by two EOT cranes of similar
capacity with lifting beam. EOT cranes
main hooks are fitted with the lifting beam and lifting beam main hook is being
utilised for lifting stator by using special sling designed for the above
purpose. Stator is placed in the service
bay within the approach of EOT crane and unloaded from Trailer / wagon as the
transportation method available in the power house. Earlier days a railway line
runs across the service bay. Now a day’s
all the stator is coming by high capacity hydraulic Trailer. Stator is unloaded by hydraulic jacks on
temporary supports in the service bay. Fix the trunion plates (04 nos) with the
body of the stator after necessary cleaning and blue matching with stator body.
This has to be fixed as per the norms because sling will be placed on it. Clean
the terminal box and do the blue matching with surface plate. This are the
preparatory work for stator lifting. Terminal Box can be placed before stator
if there is no other possibilities push it from bottom. Stator is lifted by
tandem operation with lifting beam from any of one the crane. This arrangements
to be tested before put in actual use. Necessary adjustment to be carried at
that time, to avoid any jerk during the operation.
Stator lifting by Portal crane or by strand jack
method.:-
Once
we are start erecting 500 MW /600 MW /660 MW /800 MW generators the weight of
the stator
increases considerable therefore alternative lifting arrangements
are thought of . Some of the
utilities think
about the lifting irrespective of loading TG
bay . Otherwise total TG bay need to designed taking stator weight as
one of the factor. Portal crane and
strand jack method came as solution. It has been seen availability of Portal is
a problem. In my service life we have noticed
that once we need to erect 09 numbers of stator in a year and we have
only two portal cranes. Portal dismantling , transportation and re –erecting is
03 to 04 months cycle depends on location of both the sites . We cannot erect
all the Generators required by management and to solve this problem stand jack
method of stator lifting was adopted. This type of lifting was already popular
for boiler drum lifting.
Placement of stator for this
type of lifting is very important. The stator need to be placed outside A row
column and between transformer bay and A row column. Centre line of
Generator from TG to be brought and marked for stator placement . No
axial movement is possible when stator is placed on foundation. Foundation for
jack pads and lifting structures are needed for unloading the generator
and placed on temporary supports. All other works to be done on
generator is same. Stand jack system to be erected by EOT crane and Heavy lift
Crawler crane from AB bay and Outside A row. Close co –ordination is required
from all quarters as that area includes the area of CW pipelines for Condenser. Clear approaches is required
for heavy duty crane and Hydra cranes.
As the main column pitch distance is less than the
stator length swivel arrangement is required in strand jack system. Strand jack
system is totally hydraulic and operates slowly it may take 06 to 08 hrs from start to complete the
lifting and placement operation.
LINK 1 - PLEASE CLICK HERE
LINK 2 - PLEASE CLICK HERE
really helpful content.Santek Equipment manufactures high quality EOT cranes.Manufactured according to Lift and speeds that suits your specific application.
ReplyDeleteEOT Cranes services in India
We provides a best scaffold to all industries with the wide range of sizes from industrial building, towers to large scale applications.
ReplyDeleteScaffolding contractor thompson
Mobile scaffolding platforms thompson