Increase the force of the motor
Increase the current
The force on the spinning axle can be increased by using a larger battery. This gives you more voltage which also gives you more current through the circuit with the same resistance. Remember `V=IR` if the resistance is the same and the voltage goes up so too must the current. This increased current will produce a stronger motion of force on the wire as it cuts through the magnetic field because an increased current produces an increase in the strength of the magnetic field around the wire.
Increasing the current will increase the speed of the spinning axle because more force is produced.
Increase the number of turns in the coil
The more wires that cut through the magnets magnetic field carrying the same current will produce a stronger motion of force on the wires and again the axle or spinning shaft will turn with more force. With more force a greater load can be placed at the end of the shaft. This increased force comes about because the combined wires produce a stronger magnetic field around the grouped wires.
Increase the magnetic force
One sure way to increase the force of the spinning shaft is to increase the power of the magnets either side of the wire. Magnets have the unusual property that as you move a magnet, it exerts a force on charged particles (electrons). A stronger magnetic force will push electrons more easily through a moving wire from atom to atom.