Reluctance means unwillingness to do something (it could be anything). Reluctance is an English word that has different meanings that can be defined by using different words. There is a use of this word when there is a situation where someone is afraid, hate, unfamiliar, unsatisfied with that particular work or function. All of the reasons that resist your inner self about doing something would be included in this word.


  • This happens when there are inner vibes that are continuously forcing you to step back with something. That could be because the action would not sound appropriate or there might be other reasons as well. If we become more specific with the kind of actions we are talking about, then this could be a stubborn response due to which someone is unwilling to give up on his or her ego. Not just this, but you can use the word “Reluctance” when you see someone who is procrastinating. That means this term is showing the negative side of someone’s personality if we use this on human beings.

  • The above paragraphs explain the word by using it on a human personality. But this word has a broad meaning in the world of physics or in other words in the magnetic field. As the other word for opposing is “resistance”. This resistance has the ability to oppose the electric current in a circuit. This term is used for “unwillingness” use in magnetic circuits where it works as a resistance.

:arrow_right: Reluctance In Magnetic World:

In the world of magnetic circuits, this reluctance works to oppose the magnetic flux which is flowing through the circuit. This ability will help to store magnetic energy as the magnetic field has magnetic flux that is opposed by that and ultimately reserves energy.
Mostly you will use this word in the study of circuits as it has the least use for man. If we dive into the details then you must have knowledge about magnetic fields. This basic knowledge included the unit of the magnetic circuit, the formula, and the concept behind the formula and unit.

So the unit for the magnetic circuit is “Amare’’ or “inverse henry”. The circuit is a scalar quantity that has no direction. It has a formula which is, voltage divided by current. Here voltage represents by “V” and current represents by “I”. Voltage is a source of current and flux is a magnetic circuit.

There is a detailed topic about Magnetic fields and Reluctance. Below we will discuss each and every concept that will clarify what this word means and how it works.


:arrow_right:Magnetic Reluctance:

Basically, magnetic reluctance is a term that is defined as the ratio of magnetomotive force and magnetic flux. This ratio can represent MMF / magnetic flux. This term can also be called magnetic resistance and is used to evaluate magnetic circuits. This other name clearly defines that it is to present to oppose the flux. That is why the word “Reluctance” is used as it functions to resist the situation. Another definition of this could be Ohm’s Law. Furthermore, it is a scalar quantity that has the unit “inverse henry”.

:heavy_check_mark:Applications of Magnetic Reluctance:

There are so many things where this reluctance works. All of these applications are discussed below.

  1. Use in Flyback Transformer: Increasing the resistance or reluctance makes the transformer enable you to reserve more energy for saturation. This increase in the resistance is because of the continuous air gap in the core part.

  2. There can be variations in air gaps by using movable kind of keepers. This will originate from the switch of flux that will alter the flux in the circuit. There are no changes in the magnetomotive force of the circuit.

  3. Help in the variable reluctance generator: the principle or technique that is used behind this is, variation of reluctance. These forces keep the magnetic circuit aligned and maintain a minimum air gap.

  4. Use of multimedia loudspeakers: these speakers are normally shielded which helps in reducing magnetic interference. Here the magnet of the speakers is covered with a soft iron that lowers the magnetic field.
    Magnetic Reluctance

:point_right:t2:Electrical Reluctance:

What is electrical reluctance? A analogs of resistance that functions to resist the flux to store or reserve current is Electrical Reluctance. Flux moves towards the low resisting area in a circuit.

It has a formula that has different units and symbols. The units and symbols are given here.

  • l is the length of the conductor.

  • μo is the permeability of the vacuum. This has a value that is equal to 4π Χ107

  • and has a unit Henry/meter.

  • μr is representing relative permeability.

  • A is the cross-section area of the conductor of an electric circuit.

:small_orange_diamond:What is an induction motor?

An induction motor is another type of electric motor which starts on the induction principle. The motor has two important parts. One is a stator which is a static part and the other is a rotor that rotates freely. These parts are structured separately in the motor.

:small_orange_diamond:Working of Induction Motor:

Induction Motor works on the following steps:

  • The stator has the conductors from where the alternating current or AC passes and creates a magnetic field that is time-varying.

  • Then the rotor conductor cuts the field and we know that electromagnetic induction (emf) induced in the rotors.

  • The current started flowing from the conductors that generate rotor magnetic field flux.

  • The two different fluxes that are the stator and rotor flux produce flux together that helps the rotor to rotate.

Electrical Reluctance

:heavy_check_mark:Classification of Induction Motor:

Induction Motors are classified into two types:

  1. Single Phase (Induction Motors)
  2. Three Phase (Induction Motors)

Single Phase (Induction Motors):

These induction motors cannot start themselves as the mechanism would not allow the torque to work. The net torque is zero. So the motor gets started when the starter connects the capacitor parallel to the motor. Examples of this type of motors are fans, pumps, and etc. `Without capacitors or with the damaged capacitors the fan is unable to work. So this type of motor usually needs capacitors to start.

Three Phase (Induction Motors):

Three-phase Induction Motors has 3 types of starters. The starters are:

  • Direct on line
  • Star delta
  • Autotransformer
  1. Direct On Line Starters:

These starters work with the power of motors that is below 5 k-watts. It connects with the voltage and prevents voltage-related fluctuations.

  1. Star Delta Starters:

It is used in delta-connected windings.

  1. Auto Transformer Starters:

Type of motor that has delta as well as star windings. It balances the current when the moor is getting started.

Reluctance Motor:

Operation of Reluctance Motor:

  • How does reluctance motor work? Basically, the reluctance motor is another type of electric motor. This electric motor works through non-permanent magnetic poles on the ferromagnetic rotor. This rotor has the capability to generate torque without any winding by magnetic reluctance. The specialty of this Reluctance Motor is that it can provide high power density even at a very low cost. That makes it easy to use things for so many applications.

Principles of operating reluctance motor:

It works in high-energy states to low-energy states. It doesn’t go spontaneous. The magnet and the metal connection also show the transition to a lower energy state. Magnets that cross over the metal then the metal will start to jump to connect to the magnet. This happens because of magnetic flux lines. These lines become in a lower energy state when passed from metal.

To operate this motor, you need to understand the process. To start this there is a need for a feedback mechanism that makes the coils activated. In the recent era of electronics, work has become very easy. Now you can easily purchase a useful tool.

A rotating magnetic field is present in these kinds of motors. It has a vector that represents an arrow, also has an amplitude that remains constant, and always rotates in the clockwise direction. The rotors get aligned with the magnetic field to maintain the low energy state.

To conclude everything, we could say that the Reluctance Motor is the most efficient and smart motor among all. This makes it more commercialized and more useful from an Industry point of view.

:writing_hand:t2:What are the applications of reluctance motors?

Reluctance Motors generated torque by the method of magnetic reluctance. This works by inducing non-permanent magnetic poles on the rotor.

There are different types of reluctance motors and each type has a different application. Some of the types are:

  1. Variable reluctance stepping.
  2. Synchronous reluctance.
  3. Switched reluctance.
  4. Variable reluctance.

There are so many uses of reluctance motors as they are available at a low cost. The applications are:

  • It is useful for nuclear reactors.
  • Motors also use in washing machines
  • Use analog electric meters
  • The motor is used in the hard disk of the drive motor.

Reluctance Torque:

The reluctance torque is created from the rotor. The torque is produced when the lines of the flux force the rotor to get into alignment. The torque produced after this is an additional torque as there is the torque produced by excited poles. Basically, this toque is helpful as it maintains synchronism when there is no field excitation.

Frequently ask questions:

Reluctance is a term that gives the concept of resistance in motor operations. Following are some common questions people may ask.

1. What is the difference between Permeance and Reluctance?

Comparison Between Permeance and Reluctance:


It is the measurement of flux in a magnetic current. The symbol of permeance is “P”. It is known as analogous conductance. The unit of permeance is Henry, Wb, or AT.

The formula of permeance: Flux / MMF.


Reluctance works to oppose the magnetic flux in a circuit. The symbol for reluctance is “S”. It is analogous to resistance and the unit of reluctance is 1 / Henry or AT.

The formula for reluctance: MMF / Flux.

2. What is the difference between reluctance and resistance?

Difference between Reluctance and Resistance:

What is the difference between reluctance and resistance? Below we will discuss all the differences in detail.


The resistance is used for resisting or opposing the flow. It measures the opposing current in the circuit.


The dictionary meaning of it is, the unwillingness of doing anything and in a magnetic field or circuit, the meaning of this word is, the opposition of current flow in the magnetic circuit.

3. What are reluctance and reactance?

Difference between reactance and reluctance:

The opposition that works in the magnetic field to conserve the current is Reluctance. On the other hand, reactance works to oppose the circuit element. This is because of the inductance of the element. An increase in reactance means a small amount of current while the voltage remains constant.

4. Compare Reluctance and the Inductance?

Here are the relations of inductance and reluctance. There is a very important relationship between these two. Increasing reluctance in the circuit where the current remains constant, then the flux will start to decrease. Here, for the same coil current inductance will also decrease.

5. What is the relationship between MMF and Reluctance:

MMF is the short form of magnetomotive force. Magnetic Reluctance is to measure the circuits and it is the ratio of between two. These two are MMF and the other one is magnetic flux.

What does MMF mean in electrical? It is a force (electromotive) that sets the magnetic flux. This is equal to the number of turns of the wire that has an electric current. The unit is ampere-turns.

6. What is the difference between switched reluctance motor and a variable reluctance motor?

“Switched reluctance motor” vs “Variable reluctance motor”:

Switched Reluctance Motor: In this kind of motor, on and off switches tell about the activation of the coil.

Variable Reluctance Motor: In this case reluctance depends on the rotors as the rotor gets aligned with the flux lines.

7. How does a reluctance motor become self-starting?

Reluctance motor is also called synchronous induction motor. The stator of this motor is single-phase or three-phase. If it is a three-phase stator then when we supply a stator then this will produce a magnetic field in the rotor. After this, the rotor will start rotating. That is how the motor becomes self-starting.

8. What is the relation between Reluctance and Excitation current of the transformer?

Relationship Between Reluctance and Excitation current of the transformer:
Excitation or magnetizing current is a current in which magnetizing components produce electromagnetic flux. Whereas reluctance works to resist the flow of this electromagnetic flux.


  • Reluctance is a very common word that is used in studies of motors and generators. There are so many other terms that we use when we study circuit and current.