Broken Brushed DC Motor to Operational Transformer

This instructable will go though the steps as to how you can recreate this operational and esthetically pleasing transformer I built. I built this transformer as a challenge to see if I could build my own electronic components. I also built it to personally learn more about transformers and I hope by recreating it, you will be able to also learn something new about transformers you were previously unaware of.

Tools:

1. An allen wrench
2. Drill (optional)
3. Pliers
4. Multimeter (optional)
5. Signal generator (optional)
6. Oscilloscope (optional)

Materials:

1. Electrical tape
2. two 80 tooth Tetrix Robotics gears (optional)
3. Two Tetrix max bevel gears (optional)
4. One pack of 40 mm actobotics screws
5. One pack of 16 mm actobotics screws (optional)
6. One pack of nuts to fit the screws
7. Two same size Tetrix stand off posts (optional)
8. Two Tetrix C brackets (optional)
9. Broken of Operational brushed DC motor
10. copper wire (size is dependent on personal preference)
11. Female to Female jumper wires (2 black, 1 orange, 1 green)

Use the cover image as a reference to how your finished product should look.

Simply put, a transformer transforms voltage by either increasing it, decreasing it, or keeping it constant. But transformers are way more sophisticated than that. These crazy devices are made up of two inductors wrapped around an iron core. These inductors can have multiple taps within them that allow a single transformer to power many different circuits at the same time, but these can become tedious the more a transformer has. When one coil or inductor is supplied by AC mains, a magnetic field is formed in the center of the coil and because the coils are surrounding an Iron core, the core will capture this magnetic field. As this magnetic field is passed through the secondary coil, an electrical charge is formed. This resulting electrical charge will be either less, more, or the same as the input voltage depending on the number of turns in each coil. For example, a 5:1 turn ratio will transform 120 Vrms to 24 Vrms. Likewise, a 1:5 turn ratio will transform 120 Vrms to 600 Vrms. A 1:1 transformer results in 120 Vrms from 120 Vrms and these are known as isolation transformers which isolate a circuit from the AC mains providing for a safer environment. It is important to note that as the voltage increases the current will decrease and vise versa. All these things must be considered when designing a transformer.

In this step, the only thing that must be harvested from the brushed motor is the iron core used to make an electro magnet. This piece should appear as a hallow block in a circular shape composed of laminated sheets.

steps:

1. Remove any screws securing the motor. These are typically set on the outside of the motor and are fairy obvious.
2. After removing all screws, very carefully remove the back end of the motor. The back end contains the brushes and should slide off with a little bit of force if any. Use the pliers in this step if needed.
3. Remove the hallow iron laminated block, this will be your core.
4. Remove any coils wrapped around the iron block and discard them unless you plan to use them.

In this step, the coils will be added to the iron core forming the transformer. Make sure to keep track of the number of turns in each coil. If you plan to make a power transformer, you should consider 6 turns per volt as a starting point.

steps:

1. Calculate your turn ratio. As a suggestion, a very good turn ratio is 5:1.
2. Wrap electrical tape around opposite ends of the core. This tape will ensure that current cannot electrically pass into the core.
3. Take the copper wire of your choosing and form your primary coil around one end of the iron core wrapped in electrical tape. This coil should have more windings than your secondary coil unless you desire to make a step up transformer.
4. Take the same gauge copper wire as in your primary coil and begin forming your secondary coil opposite your primary coil.
5. Leave about 3/4 of an inch out on each end of the coils. these will be used to attach your jumper wires for easy plug in installation in a circuit.
6. Take your female to female jumper wires and cut one end off of each one. use your wire strippers to strip the ends of insulation.
7. Take your soldering iron and tin the ends of each wire.
8. Using sand paper, sand down the exposed ends of each coil. Tin these ends as well.
9. Solder the jumper wires to the ends of each coil that were just tinned. The two black wires should be attached to the primary winding and the orange and green wires should be attached to the secondary winding.
10. Use glue or tape to secure all wires.

This step is optional but highly recommended to provide extra protection to your transformer.

steps:

1. Use two of your 40 mm screws and drive them though opposite ends of your iron core, not through the coils. you may consider using the drill if the holes provided are too small.
2. Attach two nuts to the end of each of the two screws inserted. these will act as spacers.
3. Slide on one of your 80 toothed gears to the bottom of your transformer directly after the nuts. These gears will add a nice aesthetic appearance and provide protection to your transformer.
4. Take your two C brackets and slide them on on the bottom right after the gear and secure them with two more nuts.
5. Bend the C brackets to form legs as shown in the cover image.
6. Take two of your 16 mm screws and two same sized stand off posts and secure them to the middle of the supporting gear on the bottom of your transformer.
7. Take your second 80 toothed gear and screw it onto the two stand off posts.
8. To add more aesthetic, you can take the two bevel gear, one on top of the other, and attached them to the top of your second 80 toothed gear as shown in the cover image.

In this step you will test your transformer if you have a multimeter, signal generator, and oscilloscope. If you only have a multimeter and signal generator, you can preform a few calculations to draw out your output sine wave. If you are only able to use a multimeter, simply take a resistance measurement of each coil to ensure the coil is not broken anywhere and to identify the primary and secondary coils (the primary resistance measurement should be larger than the secondary unless the transformer is a step up transformer). If you do not have access to any of these, skip this step.

steps:

1. Plug the primary coil into the signal generator and the secondary winding into the oscilloscope.
2. Turn on the signal generator output after setting it to the lowest possible setting.
3. Turn on the oscilloscope.
4. Gradually increase the settings and see what happens to the signal on the oscilloscope.
5. If you do not have an oscilloscope but you do have a multimeter, use the multimeter in the place of the oscilloscope and follow the calculations below to visualize your signal.

MS = multimeter signal

MS/0.707(2) = Peak to Peak output

period = 1/frequency in Hz (use the frequency from the signal generator as frequency is constant through a transformer)

If testing results are optimal:

Congratulations, you have successfully built your own transformer from a Brushed DC Motor!!!

If testing results failed:

You may consider going back and reviewing your process of operation to make sure you followed every step as clearly as possible. After making any corrections, retest your transformer. If the transformer still does not pass testing, post your issue in the chat box for additional help with troubleshooting.