Armature reaction and Lentz's law ?

In summary, armature reaction is seen in DC and synchronous machines, but not in induction machines. It is not an extension of Lenz's law, but rather a consequence. In DC motors, back EMF and Lenz's law are the same thing, while in DC generators, magnetic drag and Lenz's law are the same thing. In induction machines, Lenz's law causes torque to be developed in the same direction as the rotating magnetic field, leading to rotation. The relationship between Lenz's law and generating action in DC motors is unclear and can be confusing.
  • #1
nik235
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1) Is armature reaction seen in all machines ie DC, INDUCTION & SYNCHRONOUS machines ?
(just answer briefly, which all machines exhibit it)

2) Is back emf in DC motor nothing but LENZ'S law, or is the generating action in DC motor called the LENZ's law, or are both same, and I'm confused ? (please clarify this briefly)

3) Is magnetic drag in DC generator nothing but lenz's law, or is it motoring action in DC generator called the LENZ's law, or are both the same, and I'm just confused ?

4) is armature reaction in dc motor nothing but lenz's law extension?

5) is armature reaction in dc generator nothing but lenz's law extension ?
 
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  • #2
Not an extension of Lenz's law, but a consequence.
 
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  • #3
@maajdl, thanks mate. so 4) and 5) are consequences of AR.

also it seems INDUCTION MACHINE, doesn't experience this AR, as they're homopolar, thus i guess only DC and synchrounous machines experience AR.

But IMs, exhibit lenz's law, that's why they get torque developed in same direction as RMF, thus rotation, thus now how is lenz's law consequence.

also in DC MOTOR, back emf = lenz's law = generating action, is this statement correct or contradictory.

I'm really confused.
 

1. What is armature reaction?

Armature reaction is a phenomenon that occurs in electric motors and generators, where the magnetic field produced by the current flowing through the armature windings interacts with the main magnetic field of the machine, causing a distortion or weakening of the field.

2. How does armature reaction affect the performance of a motor?

Armature reaction can have both positive and negative effects on motor performance. It can lead to a reduction in torque and speed, but it can also improve the stability and efficiency of the motor.

3. What is Lentz's law in relation to armature reaction?

Lentz's law, also known as Lenz's law, is a fundamental law of electromagnetism that states that the direction of an induced current in a conductor will be such that it opposes the change that produced it. In the context of armature reaction, this means that the induced current will create a magnetic field that counteracts the main magnetic field, resulting in the distortion or weakening of the field.

4. How can armature reaction be minimized or controlled?

There are several ways to minimize or control armature reaction in electric motors and generators. One approach is to use compensating windings, which produce a magnetic field that counteracts the armature's field. Another method is to use interpoles, which are small auxiliary windings that produce a magnetic field that opposes the armature's field. Additionally, adjusting the design and placement of the armature windings can also help to minimize armature reaction.

5. What are the practical applications of understanding armature reaction?

Understanding armature reaction is crucial for the design and operation of electric motors and generators. It allows scientists and engineers to optimize motor performance, improve efficiency, and reduce the risk of damage to the machine. Additionally, knowledge of armature reaction is also important in the design of other electrical devices, such as transformers and solenoids.

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