Paper Clip Motor Project

• How a motor works
  • Left Hand Rule - Fingers in direction of electron flow, thumb points north.
• How to build a paper clip motor
  • Materials needed

note: Copper wire from a broken bass speaker coil can often be recycled for this project. (20 gu. wire has a diameter of 0.0320 inches or 0.8128 mm)

• Overall Design
  • The motor consists of
    • a rotor bent from a jumbo paper clip
    • stators made from common nails
    • rotor mounts (bearings) made from paper clips
    • electromagnets on the stator and rotor made from copper wire
    • brushes are created by baring the insulation on the copper wire

Fig. 1 The overall design

• Building the Rotor
  • Start by "flattening" both ends of a jumbo paper clip.
  • Straighten the inside bend in the paper clip.
  • Measure to the centre between the flattened ends then bend the ends 90 degrees up or down to create the shape as shown.
  • to wind the rotor
    • Take 1000 mm wire and mark the midpoint.
    • Wind half of the wire on one side of the rotor and one half on the other.
    • It is important that all the winding is in the same direction.
  • Apply some masking tape on the rotor as shown to keep the rotor stable in its mounts.
  • Bring the end lengths of the wire along side such that they end up beside the lower masking tape.
  • Strip the last 10 mm of the wire insulation off by scraping carefully with a knife.
  • You may wish to use a small amount of masking tape to secure these wires in position.
  • Balance the rotor to be sure it doesn't have a heavy side; this can be done by slightly shifting the windings or by small bends in the paper clip (rotor) ends.

Fig. 2 The Rotor (before windings)

Fig. 3 The Rotor (wound)

• Building the Stators
  • Nail the two nails into wood blocks as shown.
  • Wind each stator in different directions such that both end up wound in the opposite direction to the rotor when in the position shown in Fig. 3.
  • Allow some extra wire at the ends to create the brushes with.

Fig. 4 Approximate dimensions (top)

• Supporting the Rotor, Installing the Brushes
  • Straighten the large bend in both No. 1 paper clips.
  • Create a small loop in the end of the straight section with a pair of needle nose pliers.
  • Bend the paper clip at the other bend to create the support and use tacks to hold each support in place.
  • Install the rotor
  • Bare the insulation off the end of the copper wire for the brushes and support each brush as shown using two paper clips.

Fig. 5 Approximate dimensions (front)

• Adjusting and Troubleshooting
  • Before powering up check that the rotor will rotate freely in its mount. Give it a flick with your finger and is should spin 10 or so times. If it does not you may need to reduce the friction at the supports, reduce friction at the brushes or balance the rotor so it doesn't have a heavy side.
  • Bending and cleaning the brushes to have good electrical contact is always necessary. Sometimes this is best achieved with the rotor out, then install the rotor after the brushes are bent into position.
  • Place the rotor in the position shown in Fig. 3 and apply power. A well built motor will run at 3 V or less. If there is no conduction make sure you have bared the ends of the wire connected to the power supply and check the connection at the brushes. You typically need to flick the motor with your finger to get it going. If sparks fly at the brushes and it takes longer to stop rotating then you know you are close. If it stays stationary at the start position and conducts electricity then perhaps one or more of the windings are in the wrong direction. Note when the motor is stationary and conducting electricity it may conduct enormous amount of current; essentially it is a short circuit. Be sure to shut off the power if this is the case. Things may heat up and melt or burn and if you are using a battery it may blow up. I do not recommend batteries for this project for that reason, best to use a current protected adjustable power supply.
• Future Enhancements
  • Were looking into the following changes for the future;
    • perhaps use less wire on the stators.
    • possibly eliminating the use of nails and use paper clips instead for the stators, then build on one piece of wood.