AC and DC Generators
Topic #3
Research and discuss DC Generator voltage, current, and power expectations.
- direct-current (DC) generator is a rotating machine that supplies an electrical output with unidirectional voltage and current.
- Direct-current generators were widely used prior to the availability of economical rectifier systems supplied by alternators.
- Also direct current (DC), which is electricity flowing in a constant direction, and/or possessing a voltage with constant polarity. DC is the kind of electricity made by a battery (with definite positive and negative terminals), or the kind of charge generated by rubbing certain types of materials against each other.
Research and discuss AC Generator voltage, current, and power expectations.
- Certain sources of electricity (most notably, rotary electro-mechanical generators) naturally produce voltages alternating in polarity, reversing positive and negative over time. Either as a voltage switching polarity or as a current switching direction back and forth, this “kind” of electricity is known as Alternating Current (AC)
How do AC and DC generator output and uses differ?
Polarity of the voltage across the wire coils reverses as the opposite poles of the rotating magnet pass by. Connected to a load, this reversing voltage polarity will create a reversing current direction in the circuit. The faster the alternator’s shaft is turned, the faster the magnet will spin, resulting in an alternating voltage and current that switches directions more often in a given amount of time.
While DC generators work on the same general principle of electromagnetic induction, their construction is not as simple as their AC counterparts. With a DC generator, the coil of wire is mounted in the shaft where the magnet is on the AC alternator, and electrical connections are made to this spinning coil via stationary carbon “brushes” contacting copper strips on the rotating shaft. All this is necessary to switch the coil’s changing output polarity to the external circuit so the external circuit sees a constant polarity.
What function do the slip rings and commutator perform for AC and DC generators?
In general, slip rings are a part of an AC motor that transmits the energy between the machine’s stationary and rotating parts.
The main distinction between the two devices is that while a slip ring is applied in conducting power from a static to a moving part while, a split ring is adopted for DC equipment to change the flow of the current. On the other hand, the design of the slip ring is can be described as a continuous circular ring with brushes on its outside layer while a split ring is from the middle to form two halves. While slip rings are used in AC generators, split rings are needed for DC generators.
How do AC and DC generators relate to AC and DC motors?
AC and DC power generators both use electromagnetic induction to generate electricity. However, the process they use is different. An AC generator creates an alternating current that periodically reverses direction. But in a DC generator, a direct current flows in one direction.
The similarity between d.c motor and a.c. generator is that they both are electrical machines which work based on the principle of Electromagnetic Induction.
References
Blogs, News & Blogs, Slip Ring, Slip-ring (January 11, 2022)Yunus.https://slip-ring.com/slip-ring-frequently-asked-questions/
Tony R. Kuphaldt, Schweitzer Engineering Laboratories via All About Circuitshttps://workforce.libretexts.org/Bookshelves/Electronics_Technology/Book%3A_Electric_Circuits_II_-_Alternating_Current_(Kuphaldt)/01%3A_Basic_AC_Theory/1.01%3A_What_is_Alternating_Current_(AC)
