How to Build a DC Motor

History of DC motors

In 1832 William Sturgeon invented the first DC motor. Later on, Thomas Davenport further developed the motor and later patented it in 1837. A Russian engineer named Mortiz van Jacobi made the first rotating DC motor which gained its fame from it power. IN 1864 Antonio Pacinotti created the ring armature inside the DC motor which is still used today. Finally, in 1886, Julian Sprague further expanded the DC motor so that its speed of rotation was under different conditions and weights. A DC motor uses electricity and magnets to make the armature spin. When the electricity flows through the armature it becomes an electromagnet. The electromagnet then tries to aline with the permanent magnets creating rotation.

Advantages and Disadvantages of a DC motor

Advantages

• Higher starting torque
• Quick starting and stopping
• Reversing current 
• Continuous rotation

Disadvantages

• Cogging at speeds of less than 300 rpm
• Significant power loss on full wave rectified voltage
• High starting torque can damage reducers

How a DC motor works

A DC motor, or direct current, is actually very simple. When the electrical current is passed through the motor, the armature will become an electro magnet. Because it is a magnet, it will rotate to try to align with the orientation of the bar magnet. Once it has spun it will the electro magnet will repolarize itself, so it will have to roate again to align itself. This will keep happening, so the motor will spin.

DC motor applications

• electric tooth brushes
• conveyor belts
• drones
• RC cars
• fans
• many others

To build a basic DC motor you will need:

• Two strong bar magnets - £2-5
• At least a meter of copper wire - £5
• Two paper clips - £1 (for a box of 100)
• Electrical tape - £2
• styrofoam block - £3
• 9-volt battery/ D cell battery - £3
• crocodile clips - £3

Attach the two magnets on top of each other to the styrofoam block. You can use glue or double-sided tape, but there must not be anything on top of the magnet, because it might disrupt the magnetic field.

attach the paper clips to the side of the magnets with electrical tape. Make sure that the tape is tight because the paperclip might slip. The paper clips are used to move the current through the armature.

the armature is one of the most important parts of the whole DC motor. When the electrical current is passed through the paper clips and through the armature, the armature will basically become an electromagnet.

To make the armature you wrap the copper wire around your finger until there are about 6 inches of copper wire left on each side. Then, wrap the leftover copper wire around the circle that you just made to secure it. Leave about 1 inch of wire on each side.

Finally, using sand paper, sand off the ends of the copper wire. This is because the wire has a protective coating that might impair the flow of the electricity.

Without a power supply, there would be no electricity to power the motor. You can use a D-cell battery, a 9-volt battery, or a larger battery if you wish. Connect the battery to the motor with crocodile clips. Clip the clips onto the bottom of each paper clip. It might be hard to put them on because of the magnet.

Changing the orientation of the battery will also change the direction of the electrical current. If you change the orientation you might get better results with your motor.

Your motor will probably not work the first time, so you will have to constantly fiddle with the armature and the paper clips to make them line up and spin correctly.

Problems that might make your motor not work are:

• The ends of the armature are not straight so it gets caught on the paper clips
• the armature is too heavy. If this is the case make a smaller armature with fewer loops and smaller-sized loops.
• the armature is too far away from the magnet. If you attached the paper clips too far up the magnet, the magnets might not be strong enough to cause the armature to try to align itself with the orientation of the magnet.
• you might have forgotten to sand down the ends of the armature
• the battery that you are using might be dead or not strong enough

The motor is working when it is spinning constantly for a long amount of time.

Citations 

desertsun02. “Homemade DC Motor! - How to Make a Simple DC Motor! - Simple DIY Project (full Instr.).” Instructables, https://www.instructables.com/Homemade-DC-Motor-How-to-Make-a-Simple-DC-Motor-Si/. Accessed 23 February 2023.

Louie, Henry M. "Electric motor." World Book Student, World Book, 2023,

www.worldbookonline.com/student/article?id=ar176700. Accessed 3 Mar. 2023.

“Electric motor - Permanent-magnet motors | Britannica.” Encyclopedia Britannica, https://www.britannica.com/technology/electric-motor/Permanent-magnet-motors. Accessed 3 March 2023.

“DC motor, how it works? – Magnetic Innovations.” Magnetic Innovations, https://www.magneticinnovations.com/faq/dc-motor-how-it-works/. Accessed 3 March 2023.