How to Make a Dynamo Using Magnets | 12V DC Generator DIY

In this video, I am going to show you how to make a Dynamo using magnets. I did it using a motorbike ignition coil. Hi, welcome back to NewPhysicist my name is Aromal Karuvath. If you are new to this channel please subscribe and support.

I’ve created many different wind turbines for this channel but I couldn’t generate a substantial amount of electricity since the dynamo I used was less efficient. That’s why I decided to make an efficient DC dynamo that can be used to power an off-grid setup. 

I promote renewable energy sources like solar, wind, and hydro because, unless we reduce our reliance on fossil fuels it is going to be hard. Fossil fuel is not only limited but burning them emits greenhouse gases thereby harming the environment.

How to make a Dynamo using magnets

In a motorcycle, the ignition coil is used for ignition and to charge the battery. To get more power output let’s rewind the stator coil using 20 SWG Copper wire. When winding the copper make sure to change the direction after one pole is completed. Don’t ask me why we’ll discuss it later.

Take a one-foot length of cPVC pipe to make the shaft. In a motorbike, the coil is stationary, but in this project, I am going to make the coil the rotor. Making the coil the rotor means we need to use slip rings or split rings to get the power out.

To make the body of the dynamo, take a 3” PVC end cap and remove the closed end. Next, cut the outer edge to accommodate the magnets using an angle grinder. Carefully place the magnets in the groove we cut, ensuring that the poles of the nearby magnets are opposite, like NSNSNS. Then lock the magnets in place using a 4” PVC pipe. You can heat the pipe if necessary.

Now we need to fix two bearings to both ends of the stator. Use a CNC machine to cut the required shape of the mount to fix the bearings. Place the rotor shaft assembly into the dynamo stator and close it with the other bearing. Now the stator-rotor assembly is finished.

Next is the trickiest part of the project: transferring the electricity generated inside the rotating coil to the outer circuit. Since the coil is the rotor, we have to use a slip ring and carbon brush to get the power output. In motorbikes, where the coil is stationary and the magnets rotate, it’s easy to get the power out without needing carbon brushes or rings. This design saves a lot of mechanical losses and reduces maintenance.

The output of any DC dynamo will not be unidirectional. This means the direction of the current changes when the coil crosses the magnetic field. We can make it unidirectional using a commutator or a semiconductor-based rectifier circuit. In this project, I’m using a 4-diode rectifier circuit. As you can see, I’ve also used a capacitor to filter out variations in the voltage and make the output smooth.

Let’s test the output of the dynamo. I’m using a hand drill to rotate the dynamo shaft. Set the multimeter to measure the voltage. It’s reading up to 15 V. Now, switch the multimeter to measure the current. It’s reading 1.5 A. That’s great!

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How to make a Dynamo using magnets full video explanation