transformer construction

How to Make a Electric Transformer Rewinding for inverter, UPS, Devices

How to Make a Transformer for inverter, UPS, Devices


How to Make a Electric Transformer : The transformer is an electrical component is designed to change the level of voltage and current according to need.


How to Make a Electric Transformer :The electronic devices used to operate at different voltage levels delivered by the power supply companies, to operate these devices require a transformer. A transformer consists of a core of laminated silicon iron on which is wrapped a coil of insulated copper wire called magnet wire.

The first coil receives power from the grid called primary coil and this coil generates a magnetic field which stimulates a motion of the electrons in the second coil producing a different voltage and current at the output. The difference of turns of wire between the primary and secondary coil creates a proportional difference between the input voltage and output voltage of the transformer.

transformer construction

Transformer construction

How to Make a Electric Transformer : The processor that we will build in this case is 115 to 18 volts ac which is ideal for the amplifier of 300 watts


Magnate wire

Magnate wire

 Double layer magnet wire or Copper wire it  is coated with dielectric varnish used in the manufacture of generators alternators, coils, electric motors, power transformers, etc.

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Silicon iron sheets

Silicon iron sheets (these silicon iron sheets come in the shape of the letter (I) and letter (E) interspersed forming the core of the transformer.

Waxed paper

Waxed paper

Waxed paper or pressboard (this role is used to isolate the windings or coils of wire together.)It has a paraffin bath which makes it flexible and ductile. It also seals out moisture and gives heat resistance preventing it from crystallizing.

Masking tape

Masking tape

Masking tape (it is used to hold paper and wire between the windings.

Foot screws and squares

Foot screws and squares

Foot screws and squares (the screws used to tighten the plates of iron squares or brackets ( used to adjust the transformer to the chassis or cabinet



Form work (square one reel is used as support for winding the wire and prevent spreading helping the smooth narrowing of the wire. the formwork are available in various materials such as plastic, cardboard and fiberglass.

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geometrical diagram

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The geometrical diagram, 7 planes designed formwork, = which may be downloaded from our web site and then build them in straw or cardboard. It must make the pieces of cardboard gluing with glue for wood reinforced with masking tape and a coat of varnish which protects the reel from moisture giving consistency and durability.


Calculation of transformers Formula

Online tool for transformer calculate 

or use other software to calculate winding of transformer

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Before the construction of a transformer you should study our article on how to calculate a transformer. To calculate the number of turns of wire we take the core area is the product of multiplying side by side of the mold. In this case we have a formwork of 5 by 3.8 inches which gives us a core with an area of 19 square centimeters.

We take the constant 42 and divide by 19 for 2.21 turns per volt as on our case we have a voltage of 115 volts multiply by the number of turns per volt now we know how many laps given in the primary winding. For the secondary winding in this case 18 volts, multiply by the number of turns per volt and 40 turns of wire get doubles.

How to Make a Electric Transformer Construction Video:

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silicon iron plates

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Testing a electric transformer

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Transformer coiling

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Transformer coiling soldiering

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See Also:

How to make Power inverter