What’s AC Generator?

The stationary field, rotating armature type of A.C. generator. Has its field coil around the stator. And the armature coils around the rotor. While in the rotating field, stationary armature type of A.C. generator, the field coil is around the rotor. The armature is around the stator.
Brushless AC Generators

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Coming across an A.C. generator for the first time. You don’t need to get frustrated, trying to understand what it is or how it functions. This article will help you get through that.

An A.C. generator is an electric generator that. Converts mechanical energy into electrical energy. In alternative emf or alternating current. A.C. generators work on the principle of “Electromagnetic induction.”

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How To Identify An AC Generator?

You can identify an A.C. generator by recognizing all the components that make up the A.C. generator. The components are;

Magnetic field: This is a uniform field that consists of the north and south poles. And conducting coils that receive voltage from a source and produce magnetic flux.

Armature: It is the part responsible for transforming the electrical energy. The armature is where the voltage produces. It consists of coils of wire.

Rotor: The rotor is the part of rotates. You can consider it as an armature. If the output voltage produces at the armature or a field of energy makes in the area.

Stator: Unlike the rotor, the stator is a stationary part of the generator. It can either be armature or field depending on the type of generator.

Slip ring – Slip ring allows the flow of energy from a stationary to a rotating device. The slip ring is metallic and insulated from each other.

Carbon brushes: This device helps conduct the electric current flowing between the rotor and stator.

How The AC Generator Work?

The mechanical to electrical conversion is when armature rotates. Between the north and south poles of the magnetic in an axis perpendicular to the magnetic field.

An E.m.f(electromotive force) induce due to the rotating armature. Thereby producing an electric current through the slip rings and carbon brushes.

N.B. The output depends on the coil’s number of turns, the magnetic strength, and the rotating field’s speed.


An A.C. generator, also called an alternating current generator has, two types. Their working principles can differentiate this. The two types of A.C. generator are;

  • Stationary field, rotating armature
  • Rotating field, stationary armature

The stationary field, rotating armature type of A.C. generator. Has its field coil around the stator. And the armature coils around the rotor.

While in the rotating field, stationary armature type of A.C. generator, the field coil is around the rotor. The armature is around the stator.

Differences Between AC and DC Generator

A.C. generator and D.C. generator are both considered machines. And classified base on the output obtained.

1.The alternating current generated moves perpendicularly in a reverse direction.The direct current formed in a dc generator moves in one direction.
2.The A.C. generator has Slip-rings and doesn’t have commutatorsThe DC generator has commutators and doesn’t have slip-rings
3.A.C. generator used to power home appliances and small motors such as. blender vacuum cleaners E.t.cD.C. generator powers larger electric motors such as; subway systems
4.A.C. generators are very efficient as the energy losses are less.D.C. generators are less efficient due to sparking and other losses like copper, eddy current, mechanical, and hysteresis losses.

What Are Advantages Of AC Generator?

A.C. generator is used as an electrical power supply to anything. that requires alternating current.

A.C. generators are dependable because of the following advantages.

  • Simple design
  • Easy to maintain
  • Transformers are compatible with A.C. generator
  • The sizes are smaller compared to a D.C. generator
  • Over long distances, it is easy and efficient.
  • Measurement done using tong tester. And clamp meter without any obstruction to the live circuit.

e.g., automobile machine, light, fan, and vacuum cleaner.

How To Maintain An AC Generator?

Maintenance is essential to keep an A.C. generator running. The following are methods to maintain an A.C. generator.

  • Change of plugs and filters – Replace plugs after 200 hours of usage.
  • Regular Change of oil – It is expected to change oil every after every 50-200 hours of operation.
  • Adhere to storage precautions- Ensure tanks are empty. Before storing and store in cool, dry places to reduce rusting.
  • When not in use – run the engine at an interval of 30days to keep its parts lubricated.
  • Checking of bearings at intervals – It is advisable to replace after 30,000 hours of usage.

What Are AC Generator Safety Precautions?

Life and health are also important things to consider when enjoying the benefits of an A.C. generator. The following safety measures should adhere to:

  • Operate the A.C generator in a well-ventilated area.
  • Make sure you have a dry hand before handling an A.C. generator.
  • A.C. generator should turn off and allowed to cool before tuning fuel
  • Children and pets are not allowed to go close or handle an A.C. generation when in operation.
  • Try to read manual guides after buy and before usage.
  • Avoid direct plugin to a wall socket.
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What factors Affect The Output Voltage Of An AC Generator?

The factors affecting the ac generator are:

· The Strength of The Magnetic field – A higher flux density will generate a higher voltage. But, there are limits to this field’s maximum strength.

At some point, the iron will enter saturation. No matter how much more excitation you supply to the area windings. The flux density will not increase.

The saturation will cause high rotor winding losses. And iron losses in the alternator.

· The rotational speed of the rotor – An increase in the rotor speed will increase the rate. At which flux lines cut the stator windings. Thus, the output voltage increases.

Similarly, slowing the rotor will decrease the output voltage. However, this’s not usually an option for an asynchronous alternator.

Because changing rotor speed also changes output frequency. So the rotational speed usually is closely regulated to maintain constant output frequency.

· The number of turns on the stator – The output voltage is proportional to the number of turns. The magnetic field is usually fixed at the ac generator design stage. The user cannot adjust this unless the rotor windings are supplied with fixed taps.

· The Output Load on The Alternator – The winding internal resistance. will generally cause the output voltage to drop as the load current increases.

A.C. generators are majorly in high demand in regions where backup power is a necessity. Areas such as Africa, part of Asia, part of South America. What are the needs? That is the other story.

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Hey all, I'm Baymax Yan, working at a generator manufacturer and Having more than 15 years of experience in this field, and I belives that “learn and lives.” The sure thing is that I can often help my work. So I have created the blog to share all my knowledge with you. Hope my sharing helps!

4 Responses

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