can produce from corrugated fin wall type
distribution transformer tanks up to 5 MVA
and radiator type power transformer tanks up to 25 MVA.
According to its Project cover plate is cut by plasma or laser
cutting machine. Then its bushing studs, lifting lugs, thermometer pocket,
oil filling cap, active part lifting part, non-magnetic LV bushing plate and
conservator connection pipes are welded to cover the plate.
produces corrugated fin walls from
thickness of 1.2mm or 1.5mm and width of 1600mm
steel sheet metal in accordance to customer projects.
In the oil immersed transformer tanks, core is inside the transformer cooling oil. Transformer tank provides isolation of oil and the core from outside environment and is used for cooling process.
The most of distribution transformer tanks are produced with cooling fin as corrugated walls or radiators. The aim of cooling fins is to increase contact area of isolation oil with the atmosphere. In addition, in hermetic type designed transformer tanks, the corrugated walls permit a level of elasticity which is essential to provide volume change of isolation oil as it heats and cools, in connection with load and ambient temprature. This provides the tank which is totally filled (and hermeticaly sealed), with the significiant advantage of extending the transformer’s service time and reducing maintenance expencies.
In special conditions, forexample small ratings or severe dimensional limitations, the corrugated walls can be very small that they do not meet flexiblity enough, requiring the use of a oil storage to allow the expansion of the isolation oil. This oil storage makes stable the internal pressure within the acceptable limits permitted by tank flexibility. Conservator is fitted on top of the transformer tank to act as an expansion tank for isolation oil. The conservator is often fitted with a oil level indicator, oil filling cap and an air dryer (dehumidtifier) in an effort to ensure that only dry air can come into contact with the cooling oil, and only at atmospheric pressure. If the air dryer is not properly maintained, it can lose its effectiveness and allow damp air to come in contact with the cooling oil.
Transformer tanks according cooler types:
Transformer cover is the top plate of transformer where input and output bushings, oil level indicator, thermometer, tap changer and lifting lugs are located. According to its Project cover plate is cut by plasma or laser cutting machine. Then its bushing studs, lifting lugs, thermometer pocket, oil filling cap, active part lifting part, non-magnetic LV bushing plate and conservator connection pipes are welded to cover the plate. Points that should be considered in the manufacture of the tank cover;
NOTE: Applying edge bendings to cover plate increases endurance of cover.
The component which connects tank body to cover plate is named as frame.
Frames can be produced from L angles or cut and bended steel sheet. A cover plate which is cut according to its project is used as a template to be able to drill frame holes. If it is requested in project Akabe produces additional NBR gasket frame from transmission sticks. Points to be considered in the manufacture of the frame;
NOTE: Proper top surface of the frame will prevent oil leakage between the cover and the frame.
Depending on customer request corrugated fin wall machine can produce a fin wall by using A1 quality DKP (CCR) 6112 cold rolled steel sheet material. Our corrugated fin wall paramaters are as follow; steel thickness is 1.2 or 1.5mm, width is 300~1600mm and fin height is 50~400mm. To strengthen the corrugated wall, welding machine is able to weld extra steel stick to both sides of the panel. Points to be considered in the manufacture of the corrugated fin walls;
NOTE: Increasing the contact surface via corrugated wall will enhace the cooling effectiveness.
The bottom plate located on tank bottom which is cut by laser, banded by press brake and welded by MIG/MAG to bottom side of corrugated fin walls. It is protecting transformer tank againinist impacts coming from bottom side of tank. There is an oil draining valve on the side of bottom plate. Footer could be produced by MPU profile or steel sheet and welded to bottom plate.Points to be considered in the manufacture of the bottom plate and footer;
NOTE: As an oil draning valve, MV22 valve or if it is requested ball valve also can be used according to design.
NOTE: Footer is produced according to its project, can be set up to bottom plate by spot welding, interrupted welding or continous welding.
Frame, short and long side corrugated walls and bottom plate which have been produced according to their projects are assembled and transformer tank is shaped in this step by spot welding. Templates are prepared before assemling eases this process. Points to be considered in the manufacture of the assembling:
NOTE: The assembling process is one of the most important phase of the transformer tank manufacturing and the faults that will occur during the assemling will cause a lot of trouble, from the defects in the structure of the transformer tank to the stress breakages that will occur in the final welding operations.
NOTE: After the assemling process, the transformer tank is sent to the final welding process by re-measuring.
The phase where the main welding operation of the assembled transformer tank is realized is called the final welding process. At this stage, welder welds edges of the junctions with the MIG/MAG welding. Points to be considered in the manufacture of final welding process;
NOTE: In addition, If the material surface is not clean enough, the flow is high, the arc length is heigh, the welding metal is cooled fast, electrodes are wet, welding is fast, gas type is wrong, welding current and voltage is low, parts are welded in wrong order cause welding problems.
A brief overview of products and services manufactured at Akabe Trafo's factory:
Steel thickness is 1.2 or 1.5mm, width is 300~1600mm, fin height is 50~400mm and distance between fins is greater than 43 mm.
Thanks to CNC based fully automatic plasma cutting machine and break press machines, tank semi production cutting and bending operations are done in our structure.
Corrugated fin wall type distribution transformer tanks up to 5 MVA and radiator type power transformer tanks up to 25 MVA.
Transformer tank leakage test which affects tank life is performed with our design test platform. We aplply penetrant chemical to and keep tanks under 0.1~0.4 bar pressure then observe for leakages.
Bushing studs, lifting lugs, thermometer pocket, oil filling cap, active part lifting part and conservator connection pipes are welded to cover the plate.
If requested, SA 2.5 shoot blasting is appliedto tanks. Depending on customer request, spray or flow painting and kiln-drying process increases the tank resistance time.