# How to wind a DC generator coil?

• kfpanda
In summary, the design will work provided you make sure the magnets are oriented correctly and the rotor is rotated at the correct RPM. If you use a 3600 RPM motor, you will need a commutator to rectify the voltage generated by the coils. The size of the wire is decided by the current your load will draw. The number of turns on your coil(s) will decide the voltage you generate. The voltage is also proportional to RPM and strength of the magnets.
kfpanda
I want to make a dc generator and not sure my design will work. I will wind the coil on a donut shape disk and put 6 rectangular magnets on a disk rotor with North Pole face the coil. Please see attached pictures. Will this design works or have problems? Can I have one continuous coil or I should break it into 6 coils(1 for each magnet)? Also, if the rotor rpm is 3600, what gauge wire I should use for the coil so it won’t burn?

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If you rotate the magnets you will need to make an alternator and rectify the AC produced in the fixed coils. You will need to reverse each magnet so the magnetic flux through the coils keeps changing.

If you fix the magnet(s) and rotate the coils, you will need a commutator to rectify the voltage generated by the coils as they pass through the magnetic field.

The size of the wire is decided by the current your load will draw.
The number of turns on your coil(s) will decide the voltage you generate.
The voltage is also proportional to RPM and strength of the magnets.

https://en.wikipedia.org/wiki/Electric_generator#Direct_current_(DC)
https://en.wikipedia.org/wiki/Dynamo#Description

I am rotating the rotor which has the magnets. Why do we need to reverse the magnets? I see this one below works without reversing. What is wrong with my winding orientation? Also, at 3600 rpm, what gauge wire can produce a desired 36 volts? Is there a formula? Thanks

If the magnets all point the same way the flux will be constant. Alternating poles produce the greatest change in flux as it rotates. Its changing flux that produces the voltage.

kfpanda said:
I will wind the coil on a donut shape disk
This suggests you are new to this field.
kfpanda said:
What is wrong with my winding orientation?
The flat coil you show wound on a donut shaped disk will have coil turns that are not cut by the magnetic field. The magnetic lines must go one way through the area of the coil, then the other way, so the turn faces must pass alternate N and S poles of the magnet as it turns.
Again, with the right geometry the voltage can be doubled by, 1; using twice as many turns, 2; using a magnet that is twice as strong, or; 3; by turning the generator at twice the speed. What will you power with your generator? How much current will it use?
https://en.wikipedia.org/wiki/Ohm's_law

CWatters
You said a DC generator that needs something mechanical to spin the rotor. The video shows a free energy machine, which is a forbidden topic on PF. Which is it?

Temporarily moved from public view until this is answered.

The OP assured me that, despite the title, no free energy is involved. We are talking about a conventional generator.

I planned to build something like the video showing. I will sandwich the coil in the middle so the magnets field will cut through all coil turn. I want to use solar to power a small 3600 rpm motor (https://www.amazon.com/dp/B0745YDSJS/?tag=pfamazon01-20) which will run my dc generator. The generator output will go into a 36v grid tie inverter which will provide electricity for the house. I want get maximum power out of my generator. I wonder how many Amps my generator can produce at 3600 rpm without burning up and what gauge wire I should use? Thanks

kfpanda said:
I planned to build something like the video showing. I will sandwich the coil in the middle so the magnets field will cut through all coil turn. I want to use solar to power a small 3600 rpm motor (https://www.amazon.com/dp/B0745YDSJS/?tag=pfamazon01-20) which will run my dc generator. The generator output will go into a 36v grid tie inverter which will provide electricity for the house. I want get maximum power out of my generator. I wonder how many Amps my generator can produce at 3600 rpm without burning up and what gauge wire I should use? Thanks

Several things seem confused. here.
• The link leads to a reduction gear, not a motor or generator.
• You say 3600 RPM for the motor and 3600 RPM for the generator, no gear reduction is needed.
• Why do you have a motor-generator at all. Why can't you feed the inverter directly from the solar panels?

Do you have a MPPT controller for the panels?
Is your house also connected to the power grid? If yes, you need a utility approved interface device to be legal.

That link looks like a motor to me. Can I use it as a motor? No gear reduction needed. The solar panels for 3k watt are more expensive compared to my generator if I can make it. I don’t need mppt to charge batteries. I only need power for my ac during summer days. My house is connected to the power grid. Will my generator work? Thanks

Your motor-generator will necessarily lose energy. You must put more solar power into the motor than you will get out of the generator. Therefore, it will need more panels with the motor-generator, not fewer. Your thinking us upside down on that point.

It is absolutely forbidden in most places to generate your own power and still be connected to the grid without special interfaces that protect utility workers outside your property.

You really need the advice of an expert local consultant on this. It is not a DIY project for someone like you.

You maybe right. I just want to try to see if my design works. Do you think my generator can produce any electricity ? Thanks

I fear that if I say yes, that you will go ahead and try it without the required safety interface to the grid. PF rules forbid discussion of dangerous topics in public.

berkeman

## 1. How many turns should the coil have?

The number of turns in a DC generator coil depends on the specific design and intended use of the generator. Generally, the more turns in the coil, the higher the voltage output. However, too many turns can also cause overheating and other issues. It is important to consult the specifications of the generator or seek guidance from an expert when determining the appropriate number of turns for a coil.

## 2. What type of wire should be used for the coil?

The type of wire used for a DC generator coil can impact its performance and durability. Generally, copper wire is the most commonly used material for generator coils due to its high conductivity and ability to withstand high temperatures. The gauge of the wire may also vary depending on the size of the generator and its intended use.

## 3. How do I determine the direction of winding for the coil?

The direction of winding for a DC generator coil is important for its proper functioning. The direction of winding can be determined by the direction of rotation of the armature and the magnetic field of the generator. The wire should be wound in the same direction as the rotation of the armature and against the direction of the magnetic field.

## 4. What is the best technique for winding a coil?

The technique for winding a coil may vary depending on the specific generator and its design. Some common techniques include hand winding, machine winding, and layer winding. It is important to follow the manufacturer's instructions or seek guidance from an expert when winding a DC generator coil to ensure proper and efficient winding.

## 5. How can I ensure the coil is wound tightly?

To ensure the coil is wound tightly, it is important to maintain constant tension on the wire while winding. This can be achieved by using a tensioning device or by carefully guiding the wire with your hands. It is important to avoid any loose or overlapping wires, as this can affect the performance of the coil and the generator.

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