Discover how an electrical transformer is made from start to finish.
Transformers (no, not that kind) are vital in any country’s power grid. Designed to act as a passive component in the transfer of electrical energy from one circuit to another (or more), most also act as buck or boost converters for currents.
This is quite an old technology and today comes in a wide range of designs and sizes depending on their use. But have you ever wondered how these critical electrical devices are made?
Let’s follow the one that arises from manufacturing to installation.
Step 1: Craft the Basic Components
At least for this particular model, the first step is to design and create the basic components. In this case, some of its delicate circuits are designed using a computer-aided design software package.
These designs are then fed into a CNC machine that specializes in plasma cutting. The parts, which had to be manufactured in the factory, begin our life as large sheets of sheet metal.

These are fed into the CNC machine, which then cuts the part design into large batches. Other automated machines can also be used to physically punch holes and other features through sheet metal.
Once this is done, the finished sheets are then taken out of the machine and passed on to specialist workers who separate each component by hand, if necessary.

Parts that require additional shaping are then placed in a set of other machines to press them into shape. This is done by human workers, who placed the parts under an automated press to bend the sheets into angles or shapes as needed.
The completed pieces are then stacked, ready for the next stage of construction.

Other parts, such as steel rods, are also shaped and cut as needed using other specialized machines in the factory. If necessary, these lengths of metal rod are then fed into automated lathes to shape them into other specialized parts ready for the transformer.

Holes and other features are also machined into the parts as required. Most of this process is automated, but may require human intervention for delicate parts or changing drill heads etc.

After the parts are made, they are then stacked and stacked in batches, ready for the main transformer assembly later.
Step 2: Checking the quality and refining the parts
Once the main parts are complete, the next step is to perform a thorough check of each one. This is done by specialist machinists who check each piece individually and polish or hone them as needed.
This might require sanding off any remaining metal barbs or just giving them a general polish.

Other parts, such as the front cut sheets, are also refined, if necessary, using bench drills and other tools. For example. screw holes are beveled and recessed, etc.
Step 3: Begin assembly
Once all major components are complete, the next step is to start assembling the transformers. The first major electrical wiring for the transformer is prepared.
This requires removing some layers of the sheath to expose the metal wires inside. In this factory, this is done by hand by trained and experienced electrical engineers.

Once this is done, the electrical terminals are connected and crimped into place on the cable cores as required. If necessary, new insulation is added and heat shrunk in place as required.

Smaller electrical wires also receive similar treatment but, obviously, on a much smaller scale.
This done, the other parts of the transformer are then soldered and assembled as required. In this case, this is also carried out by specialized human workers.
Then all the main parts of the transformer are then assembled as required. Like other parts of this phase of the process, this is all done by hand.

Nuts and bolts are firmly fixed in place using power screwdrivers, and other parts are hammered into place as needed.
Once the main mechanical parts are assembled, the next phase is to start completing the transformer circuits. This is done, as before, by specialist electrical engineers to ensure it is done correctly and with precision.

Switches, levers and other parts are also assembled and added to the transformer main circuit breakers as well.

Brushes, coils and other major transformer components are also assembled, as required.
Step 4: complete the assembly
With all the major parts ready for installation, the last part of the process is to put all the parts together in one package. More specialized workers begin to connect the main parts together and mount them on the frame and on the transformer.
The completed parts are then installed in place in the main cabinet or transformer shell. More and more parts are then added until the final transformer structure is finally complete.

The wiring is then completed and the entire transformer, including its wiring and control panels, undergoes a series of quality checks to ensure it is fit for purpose before being dispatched.
Once there, some final modifications are made to the transformers to ensure they can fit in and connect to the electrical system of the building in question. Conduits, cable runs, etc. are all made ad hoc for the site until the transformer installation is complete.
If you enjoyed watching how transformers are made in a factory, might you enjoy watching another product take shape? How about, for example, seeing how garbage trucks are made?