Generate AC/DC w/o Contact Brushes: Is It Possible?

In summary, it is possible to build an AC or DC generator without contact brushes by using an induction motor and adding a capacitor across the output. This method allows the motor to act as a stand-alone generator, with the right value of capacitor and a fast enough spinning speed. There are resources available online for more information and instructions on how to do this.
  • #1
FulhamFan3
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I just saw a demonstration of an induction motors and was wondering if its possible to build an AC or DC generator without contact brushes? The only way I can think of is if you have a permanant magnet spinning near or within a coil or wire. Is there anyway to produce a magetic field with just kinetic motion? I've searched the net and haven't found any explanation. If you have a link please include it.
 
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  • #2
Yes. Most a/c generators anyway are inductive.
 
  • #3
Most motorcycle alternators have no brushes. There is a stator field coil held in place from one side, a steel rotor comprised of 2 halves with a zigzag separation cantilevered in from the other side, and pickup coils on the outside. It works the same as an automotive unit except that since it only has a bearing on one side, the field coil can come in from the other and needs not rotate. In the automotive unit, there are bearings on both sides so slip rings and brushes are needed to activate the field coil.
 
  • #4
Originally posted by FulhamFan3
I just saw a demonstration of an induction motors and was wondering if it's possible to build an AC or DC generator without contact brushes?

Yes, and you can even convert a standard AC induction motor into an AC generator. All motors act as generators (that's why a motor uses more energy when you ask it to perform more work, and why a motor stops drawing energy if allowed to spin frictionlessly.) AC induction motors are a little weird, but since they already are generators inherently, there must be a way to use them as stand-alone generators.

The secret: add a capacitor across the output. Then, as the rotor spins, a large AC voltage builds up and a large current exists between the motor coil and the capacitor. Spin the motor fast enough, and choose the right value of capacitor, and you'll have a 120VAC 60Hz generator.

See: http://www.qsl.net/ns8o/Induction_Generator.html
 

1. Can AC/DC be generated without using contact brushes?

Yes, it is possible to generate AC/DC without using contact brushes. This can be achieved through various methods such as electromagnetic induction, rotating magnetic fields, and solid-state circuitry.

2. How does electromagnetic induction generate AC/DC without contact brushes?

Electromagnetic induction involves using a changing magnetic field to induce a current in a conductor. This method is commonly used in generators to produce AC/DC without the need for contact brushes.

3. What are the advantages of generating AC/DC without contact brushes?

The main advantage is that there is less wear and tear on the equipment since there are no contact brushes to replace. This also leads to a longer lifespan and decreased maintenance costs. Additionally, there is a reduced risk of electrical sparking and fires.

4. Are there any limitations to generating AC/DC without contact brushes?

One limitation is that the efficiency of the process may be lower compared to using contact brushes. Additionally, the initial cost of implementing alternative methods may be higher. However, with advancements in technology, these limitations are becoming less significant.

5. What are some common applications for generating AC/DC without contact brushes?

This method is commonly used in various industries, including power generation, transportation, and renewable energy. It is also used in household appliances, electronic devices, and industrial machinery.

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