Slide 1
A generator turns mechanical work into electrical energy
A generator converts mechanical work into electrical energy through electromagnetic induction. A moving magnetic relationship induces voltage in windings.
More to Read
The mechanical input may come from a turbine, engine or another source. The generator is the conversion stage, so its electrical output cannot be assessed without the energy supplied by the prime mover.
Slide 2
Rotation and pole arrangement set the alternating rhythm
In many generators, rotation produces alternating voltage. The electrical frequency depends on rotational speed and magnetic pole arrangement.
More to Read
More pole pairs allow a given electrical frequency at a lower rotational speed. This helps match generator design with the very different speeds of water turbines, engines and other drives.
Slide 3
Drawing current creates an opposing turning effect
When current flows to a load, the generator experiences an opposing torque. Maintaining speed requires the driving machine to supply corresponding work.
More to Read
Connecting a load can slow an uncontrolled generator. A governor or controller adjusts mechanical input or power conversion so the system reaches an appropriate operating balance.
Slide 4
Voltage regulation responds to speed, field and load
Output voltage depends on the machine’s magnetic field, speed and load. Regulation keeps it within the range required by connected equipment.
More to Read
In an excited generator, changing field current can help control voltage. Power-electronic interfaces provide another route, especially when variable mechanical speed is desirable.
Slide 5
The whole energy chain has losses
The generator loses some input energy as heat and friction. The upstream turbine or engine and downstream electrical equipment add their own losses.
More to Read
Multiplying the efficiencies of successive stages gives the overall fraction delivered for use. A high generator efficiency therefore does not establish that the entire energy system has the same performance.
Sources
- Motors, Generators, and Transformers
OpenStax
- How Hydropower Works
US Department of Energy