Building a dc motor: what you’ll need
There are certain items you’ll need for building your own DC motor, to ensure it’s all torque and not just wires.
Items you’ll need;
- At least a meter of copper wire
- Aluminum foil
- 2 long rigid copper wires
- 4 screws
- A piece of wood that’s twice the length and width of your motor to ensure it balances well
- Strong magnets
- 2 electrically conductive screws
- 2 regular angle brackets and 2 slotted angle brackets
- A sharpened pencil (both sides)
- Sticky tape
- A multimeter
After getting all of these ready, then you are SET.
Build the coil base
This is the foundation of your DC motor and getting it wrong here has jeopardized the entire project.
Get your sharpened pencil and pass it through the Styrofoam. In case you’re wondering how far it should go; a quarter of the pencil length is ideal. The next step will involve covering it with the copper coil.
Dress the coil base with the coil
Before wrapping the coil, peel out the end of the wire to ensure efficient conduction of electricity. To make the stripping off easy, use the sandpaper to rub off on the ends of the wire.
Tightly wrap the copper wire around the base; it’s better to wrap one side of the Styrofoam before moving to the next.One important tip not to forget is to make sure both sides are tied equally.
Now, remember that the more turns of wire, the higher the torque your motor will generate. So, if you want a high-torque DC motor, it’s best to use a long copper wire.
Test the connection
This step is really important, because how do you go ahead to build a DC motor on the wave of “maybe the connections are secure” without checking it?
That’s wrong. To test the electrical connection of the wire, get your multimeter and put it in continuity mode, also called beep mode.You’ll do a beep test where each lead of the multimeter will touch a different end of the coil.
If you don’t hear a beep, then you have done it wrong in step 2, and if you hear a beep sound, you are good to go.
In case you’re wondering what next to do; go back to step 2 because your connections are not working,Get your sandpaper and sand down the ends of the wire (more this time).
Rough up the ends, and try again. You should hear a beep sound after this, and if not, keep repeating step 2 until it beeps.
You can learn about how to test and troubleshoot brushless motors
1. Improve the electrical connections
The electrical connection of the coil base needs to be at its optimal performance for your DC motor to operate efficiently.
Cut two strips of aluminum foil – 1.7 cm wide and with enough length to go around the wire tips multiple times. Use the foil to wrap the ends and ensure you wrap it tightly.
If you are skeptical about it staying in place, then use your sticky foam. But be careful with the sticky tape placement so it doesn’t alter the electrical connection – it’s advisable to use just a thin piece of tape.
2. Check connections again
Yes, you read that right. Checking the connections again might seem like a waste of time because you are pretty certain you did everything right, however, it’s not.
Imagine a scenario where you build the entire DC motor only to see that it doesn’t conduct. Oops, that’s all your efforts down the drain.
Moving on, after building the base, get your multimeter and perform another beep test to be sure it’s conducting. If you hear the beep sound, then let’s advance to the next step, but if not, go back to step 4 and repeat the process.
Make the commutator
To make the commutator, get two pieces of aluminum and use it in wrapping the Styrofoam and coil.Create two half circles of the coil that’ll run through the entire length of the axle.
Now, stick them down on top of the wire ends. To secure it in place (to the side of a pencil) use sticky tape. Note that, the commutator and coil must align properly.
This is so that when the torque is at its highest, the two electrical contacts will be in touch. Also, when the coil is vertical, the gaps in the commutator need to be horizontal. And even when the coil is horizontal, the commutator has to be horizontal.
1. To effectively build a commutator, follow these steps
Attach the wires to the pencil using a pencil close to the coil. Ensure each wire is placed under where the commutator section is positioned.
The wires need to be kept down, so they are on the two opposite horizontal sides of the axle, especially when the coil is horizontally placed. Carefully fold the first foil, get the correct width, and wrap it on only one end of the pencil.
Use your sticky tape to hold it in position at the top and bottom of the pencil. Get the other piece of foil; fold and wrap it around the other end of the pencil. Use your sticky tape and hold it in place too.
If done correctly, the finished product should be a pencil wrapped with two strips of foil with a tiny gap in between. The tiny gap is what helps the motor generate constant torque in the same direction.
Construct the base
The base in this context is the stator, and it’s the stator that keeps the spinning rotor in place. To build a stator, you’ll need your angled brackets with slots; this is for the axial direction of the motor. Note that, you are not making use of the wide side, but rather the long side of the wood.
1. To correctly construct the stator
- Measure the pencil and highlight the wood at the desired distance
- Using your screw and washer, screw in the slotted angle. Don’t secure it too tight, so you can still move your pencil rotor.
- Screw the regular angle brackets at the tip of the board – make sure it’s in the middle
- Put the pencil into the slotted bracket, and ensure it’s positioned in a way the pencil can rotate without falling off
- Tighten the slotted bracket to keep it in place
That’s all for building a stator; your next move is to connect the wires to the power supply.
2. Connect the wires for current
At this point, you are expected to have your rotor and stator ready, all that needs to be done is get it powered right up. Because your motor is most definitely just a piece of metal if it doesn’t generate electricity.
To properly attach the wires for current;
- Fasten the two electrically conductive screws to the commutator’s end
- Cut off the excess stiff wires at the end
- Cover each end of the trimmed wires around each screw
- Position the wire in a way that its brush can come in contact with the commutator
- Attach the wire in place with sticky tape, so it stays in place even when the rotor spins.
- The next step is to be sure you did everything right.
3. Test the connections
Never get tired of beep-testing. For the last time, get your multimeter and test the connections to be sure they are working. As always if you hear a beep sound you are good to go.
Do a final and thorough double-checking of the commutator and the connections to be sure they are all properly secured.
4. Kickstart your dc motor
Before turning on your motor, connect the magnets to the normal angled brackets. Then you can proceed to connect your power supply clips to the conductive screws.
Switch the power on, but note that it might not start running on its own. Just give it a little nudge to get it running, and that’s all. You have successfully built your DC motor!
Building a DC motor is not an impossible task, and if you are looking for a worthy Physics project, this is your best bet.
Yes, you might encounter some minor challenges with connections, screws, and the commutator, but don’t let that deter you. These are common errors that can be handled easily.
We hope this article was well-detailed and explanatory to help you build your first DC motor. If you have other questions, you can click here to contact Donghui Motor. We have professional staff to answer your questions.
Related reading: How To Safely Make A Coreless Motor