The Generator Effect
Higher Tier Only
- Electromagnetic (EM) induction is used to generate electricity
- EM induction is when:
A voltage is induced in a conductor or a coil when it moves through a magnetic field or when a magnetic field changes through it
- This is done by the conductor or coil cutting through the magnetic field lines of the magnetic field
- This is often referred to as the generator effect and is the opposite to the motor effect
- In the motor effect, there is already a current in the conductor which experiences a force
- In the generator effect, there is no initial current in the conductor but one is induced (created) when it moves through a magnetic field
Generator Effect in the Laboratory
- A potential difference will be induced in the conductor if there is relative movement between the conductor and the magnetic field
- Moving the electrical conductor in a fixed magnetic field
- When a conductor (such as a wire) is moved through a magnetic field, the wire cuts through the fields lines
- This induces a potential difference in the wire
Moving an electrical conductor in a magnetic field to induce a potential difference
- Moving the magnetic field relative to a fixed conductor
- As the magnet moved through the coil, the field lines cut through the turns on the coil
- This induces a potential difference in the coil
When the magnet enters the coil, the field lines cut through the turns, inducing a potential difference
- A sensitive voltmeter can be used to measure the size of the induced potential difference
- If the conductor is part of a complete circuit then a current is induced in the conductor
- This can be detected by an ammeter
Generator Effect in the Large-Scale Generation of Electrical Energy
- EM Induction can be used to generate electricity on a large scale by replacing the moving wire with a spinning coil
- An a.c (alternating current) generator looks very similar to a motor, but instead of connecting it to a power supply, a coil is spun to produce electricity
- As the coil rotates, it cuts through the field lines
- This induces a potential difference between the end of the coil, which also then creates a current
- The electricity produce is in the form of a.c which can be found in the mains supply of a building
- This is also called an alternator
A.C Generator