Experiment

Materials

-PASCO Permanent Magnet Motor Kit

-Power source

-Cables

-Camera

-Optional(Multimeter)

Physics Behind it

In a Permanent Magnet motor a coil of wire (called the armature) is arranged in the magnetic field of a permanent magnet in such a way that it rotates when a current is passed through it.

Procedure

First you are supposed to connect the power source to the motor HINT! It is completelly dependant how the motor will act according to how you connect it. Because the current will flow a different direction so the motor will spin in a different direction.

Then simply turn on the power source and with a physical help the motor will start rotating. You can experiment and add or reduce the voltage being induced in the motor

Principle

An electric current is a flow of electric charge. Electric charge flows when there is voltage present across a conductor. In this case being the motor.Direct current (DC) is the unidirectional flow of electric charge. Direct current is produced by sources such as batteries, solar cells, and commutator-type electric machines. Direct current may flow in a conductor such as a wire, but can also flow through semiconductors, insulators, or even through a vacuum as in electron or ion beams. The electric charge flows in a constant direction.

Now, when a coil of wire is moving in a magnetic field a voltage is induced in the coil - so the current (which is caused by applying a voltage to the coil) causes the armature to rotate and so generate a voltage.

It is the nature of cause and effect in physics that the effect tends to cancel the cause, so the induced voltage tends to canPcel out the applied voltage (indeed were the effects to add, we should have a perpetual motion machine!).

Voltage is electrical pressure. Current is electrical flow. Pressure tends to cause movement, or flow so an electrical pressure is a force which moves electricity - or an 'electromotive force' (EMF).

Right Hand Rule

The induced voltage caused by the armature's movement is a 'back EMF' - 'back' because it tends to cancel out the applied voltage so that the actual voltage (pressure) across the armature is the difference between the applied voltage and the back EMF.

The value of the back emf is determined by the speed of rotation and the strength of the magnet(s) such that if the magnet is strong the back emf increases and if the speed increases, so too does the back emf. It follows from this that if you use a weaker magnet to make a particular motor, you will get a higher speed motor!