These are common steps in troubleshooting your motor:

  1. Make sure that your rotor spins freely if you give it a slight push with your hand.
  2. Test your electromagnet. Connect one 1.5V battery to electromagnet wires briefly. The electromagnet should push the closest magnet on the rotor. The rotor should turn 45° if you have 4 magnets on a rotor, or 90° if you have 2. If it does not – switch the wires.If your electromagnet does not work, it may be shorted. Sometimes re-winding the electromagnet may solve this problem.
Problem Cause Solution
Newly assembled motor does not work: rotor does not spin. Rotor is in a "dead spot" – the magnet is outside of reed switch working range. This usually occurs with 2 magnet rotors. The rotor will not start spinning on its own. Give it a slight push.
Rotor is jammed. Find the exact cause and fix the problem. This may require breaking off the stands and reattaching them to the board. You may try to lubricate the axles with WD-40 or any other lubricant.
Electromagnet attracts the magnets instead of repelling them. Switch the battery connection wires.
Bad connection in wiring. Thoroughly clean the wires to remove the insulation.
Reed switch is too far from the rotor. Move reed switch closer.
Reed switch does not function when a magnet passes near its center. The most sensitive part of the reed switch is not in the middle of it, but more to the side. Move the reed switch left or right.
The battery is dead or battery voltage is low. Get a new battery. Increase the voltage by adding an extra battery.
One of the magnets is not repelling. Tear this magnet off and glue it upside down. All of the magnets should have the same pole
facing outside.
Motor worked fine for a while but then stopped working. The battery is dead or battery voltage is low. Get a new battery. Increase the voltage by adding an extra battery.
If you use high voltage (6V or higher) you can see a blue spark inside of the reed switch. Sometimes it may weld the contacts together. Disconnect the battery. Flick the reed switch tube slightly. In most cases it will fix the problem temporarily. Afterwards it is recommended to lower the voltage or connect a ZNR parallel to the reed switch. You may also need to replace the reed switch.
The electromagnet gets hot. Not enough wire used for the electromagnet. Make sure that the electromagnet coil has enough wire. Use almost all the wire from the spool.
Short connection inside the electromagnet. Re-wind the electromagnet. It is better to use a new spool of wire, but sometimes the old wire may still work.
If you need to disassemble the rotor…   This operation may require quite a bit of strength. Disassemble the rotor with a rocking motion as if trying to break it and at the same time pulling the ends out.


  1. We have kit #3 and the motor only works when all four batteries are installed.

    • If your rotor rotates freely and you used all the wire when making electromagnet most likely it is usage of jumper wire. Did you use jumper wire? 1, 2, or 3 batteries will not work if you don’t.

      There are different types of battery holders so jumper wire has to be inserted differently in each case. Most likely you have a battery holder that matches the following:

      This is a different kit but it does not matter. Look at step 24 – it will show the proper usage of the jumper wire.

      You batteries may be also depleted and you might need to use new ones.

      Hope that helps!

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