There are two types of electrical generators - AC and DC generators. AC generators, also called alternators, convert mechanical energy into alternating electrical energy, while DC generators produce direct current. Electric motors operate by using a current in a loop of conductor to generate opposing Lorentz forces on opposite sides of the loop, causing the loop to rotate. Alternating current has a root mean square (RMS) value which is the maximum value divided by the square root of two and is used to calculate average power in a resistive circuit with AC.

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11. Electrodynamics
Physics
Grade 12

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Electrical generators
Electrical generators convert mechanical energy into electrical energy.
There are two types of generators - AC and DC. An AC generator is also called an
alternator.
AC generator

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Electrical generators contd.
DC generator

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Electric motors
An electric motor is a device that converts electrical energy into mechanical energy.
The Lorentz force is the force experienced by a moving charged particle in an electric and
magnetic field. The magnetic component is:
An electric motor works by using a source of emf
to make a current flow in a loop of conductor such
that the Lorentz force on opposite sides of the loop
are in opposite directions which can cause the loop
to rotate about a central axis.
F=qvB

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Alternating current
The root mean square (rms) value is the maximum value of the quantity can have divided by 2.
RMS values are used for voltage and current when dealing with alternating current.
The average power dissipated in a purely resistive circuit with alternating current is:
Irms=
Imax
√(2)
V rms=
V max
√(2)
Pav=Irms V rms=
1
2
Imax V max

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