Back EMF Equation of DC Motor Calculator

✖Number of Poles is defined as the number of poles in an electrical machine for the flux generation.ⓘ Number of Poles [n]			+10% -10%
✖Magnetic flux (Φ) is the number of magnetic field lines passing through the magnetic core of an electrical dc motor.ⓘ Magnetic Flux [Φ]			+10% -10%
✖The number of conductors is the variable we use for getting the correct number of conductors placed in the rotor of a dc motor.ⓘ Number of Conductors [Z]			+10% -10%
✖Motor Speed is the speed of the rotor(motor).ⓘ Motor Speed [N]			+10% -10%
✖The Number of Parallel Paths in a DC machine refers to the number of independent paths for current to flow in the armature winding.ⓘ Number of Parallel Paths [n_\|\|]			+10% -10%

✖The Back emf opposes the current which causes it in any dc machine.ⓘ Back EMF Equation of DC Motor [E_b]

⎘ Copy

👎

Formula

✖

Back EMF Equation of DC Motor

Formula

`"E"_{"b"} = ("n"*"Φ"*"Z"*"N")/(60*"n"_{"||"})`

Example

`"24.94334V"=("4"*"1.187Wb"*"14"*"1290rev/min")/(60*"6")`

Calculator

LaTeX

Reset

👍

Download DC Motor Characteristics Formulas PDF PDF Image

Back EMF Equation of DC Motor Solution

STEP 0: Pre-Calculation Summary

Formula Used

Back EMF = (Number of Poles*Magnetic Flux*Number of Conductors*Motor Speed)/(60*Number of Parallel Paths)
E_b = (n*Φ*Z*N)/(60*n_||)
This formula uses 6 Variables

Variables Used

Back EMF - (Measured in Volt) - The Back emf opposes the current which causes it in any dc machine.
Number of Poles - Number of Poles is defined as the number of poles in an electrical machine for the flux generation.
Magnetic Flux - (Measured in Weber) - Magnetic flux (Φ) is the number of magnetic field lines passing through the magnetic core of an electrical dc motor.
Number of Conductors - The number of conductors is the variable we use for getting the correct number of conductors placed in the rotor of a dc motor.
Motor Speed - (Measured in Radian per Second) - Motor Speed is the speed of the rotor(motor).
Number of Parallel Paths - The Number of Parallel Paths in a DC machine refers to the number of independent paths for current to flow in the armature winding.

STEP 1: Convert Input(s) to Base Unit

Number of Poles: 4 --> No Conversion Required
Magnetic Flux: 1.187 Weber --> 1.187 Weber No Conversion Required
Number of Conductors: 14 --> No Conversion Required
Motor Speed: 1290 Revolution per Minute --> 135.088484097482 Radian per Second (Check conversion here)
Number of Parallel Paths: 6 --> No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

E_b = (n*Φ*Z*N)/(60*n_||) --> (4*1.187*14*135.088484097482)/(60*6)

Evaluating ... ...

E_b = 24.9433380970217

STEP 3: Convert Result to Output's Unit

24.9433380970217 Volt --> No Conversion Required

FINAL ANSWER

24.9433380970217 ≈ 24.94334 Volt <-- Back EMF

(Calculation completed in 00.004 seconds)

You are here -

Home » Engineering » Electrical » Machine » DC Machines » DC Motor » DC Motor Characteristics » Back EMF Equation of DC Motor

Credits

Created by Prahalad Singh

Jaipur Engineering College and Research Centre (JECRC), Jaipur

Prahalad Singh has created this Calculator and 100+ more calculators!

Verified by Payal Priya

Birsa Institute of Technology (BIT), Sindri

Payal Priya has verified this Calculator and 1900+ more calculators!

< 25 DC Motor Characteristics Calculators

Supply Voltage given Overall Efficiency of DC Motor

Go Supply Voltage = ((Electric Current-Shunt Field Current)^2*Armature Resistance+Mechanical Losses+Core Losses)/(Electric Current*(1-Overall Efficiency))

Machine Construction Constant of DC Motor

Go Constant of Machine Construction = (Supply Voltage-Armature Current*Armature Resistance)/(Magnetic Flux*Motor Speed)

Motor Speed of DC Motor given Flux

Go Motor Speed = (Supply Voltage-Armature Current*Armature Resistance)/(Constant of Machine Construction*Magnetic Flux)

Magnetic Flux of DC Motor

Go Magnetic Flux = (Supply Voltage-Armature Current*Armature Resistance)/(Constant of Machine Construction*Motor Speed)

Back EMF Equation of DC Motor

Go Back EMF = (Number of Poles*Magnetic Flux*Number of Conductors*Motor Speed)/(60*Number of Parallel Paths)

Motor Speed of DC Motor

Go Motor Speed = (60*Number of Parallel Paths*Back EMF)/(Number of Conductors*Number of Poles*Magnetic Flux)

Overall Efficiency of DC Motor given Input Power

Go Overall Efficiency = (Input Power-(Armature Copper Loss+Field Copper Losses+Power Loss))/Input Power

Armature Current of DC Motor

Go Armature Current = Armature Voltage/(Constant of Machine Construction*Magnetic Flux*Angular Speed)

Armature Current given Electrical Efficiency of DC Motor

Go Armature Current = (Angular Speed*Armature Torque)/(Supply Voltage*Electrical Efficiency)

Supply Voltage given Electrical Efficiency of DC Motor

Go Supply Voltage = (Angular Speed*Armature Torque)/(Armature Current*Electrical Efficiency)

Electrical Efficiency of DC Motor

Go Electrical Efficiency = (Armature Torque*Angular Speed)/(Supply Voltage*Armature Current)

Armature Torque given Electrical Efficiency of DC Motor

Go Armature Torque = (Armature Current*Supply Voltage*Electrical Efficiency)/Angular Speed

Angular Speed given Electrical Efficiency of DC Motor

Go Angular Speed = (Electrical Efficiency*Supply Voltage*Armature Current)/Armature Torque

Mechanical Power Developed in DC Motor given Input Power

Go Mechanical Power = Input Power-(Armature Current^2*Armature Resistance)

Total Power Loss given Overall Efficiency of DC Motor

Go Power Loss = Input Power-Overall Efficiency*Input Power

Armature Torque given Mechanical Efficiency of DC Motor

Go Armature Torque = Mechanical Efficiency*Motor Torque

Motor Torque given Mechanical Efficiency of DC Motor

Go Motor Torque = Armature Torque/Mechanical Efficiency

Mechanical Efficiency of DC Motor

Go Mechanical Efficiency = Armature Torque/Motor Torque

Converted Power given Electrical Efficiency of DC Motor

Go Converted Power = Electrical Efficiency*Input Power

Input Power given Electrical Efficiency of DC Motor

Go Input Power = Converted Power/Electrical Efficiency

Overall Efficiency of DC Motor

Go Overall Efficiency = Mechanical Power/Input Power

Output Power given Overall Efficiency of DC Motor

Go Output Power = Input Power*Overall Efficiency

Core Loss given Mechanical Loss of DC Motor

Go Core Losses = Constant Loss-Mechanical Losses

Constant Losses given Mechanical Loss

Go Constant Loss = Core Losses+Mechanical Losses

DC Motor Frequency given Speed

Go Frequency = (Number of Poles*Motor Speed)/120

Back EMF Equation of DC Motor Formula

Back EMF = (Number of Poles*Magnetic Flux*Number of Conductors*Motor Speed)/(60*Number of Parallel Paths)
E_b = (n*Φ*Z*N)/(60*n_||)

How does back EMF affect supply voltage?

As the back emf depends on the current their value also decreases. The magnitude of the back EMF is nearly equal to the supply voltage. If the sudden load is applied to the motor, the motor becomes slow down. As the speed of the motor decreases, the magnitude of their back emf also falls down.

How to Calculate Back EMF Equation of DC Motor?

Back EMF Equation of DC Motor calculator uses Back EMF = (Number of Poles*Magnetic Flux*Number of Conductors*Motor Speed)/(60*Number of Parallel Paths) to calculate the Back EMF, Back EMF Equation of DC motor shows that a motor has coils turning inside magnetic fields, and a coil turning inside a magnetic field induces an EMF. This EMF, known as the back EMF, acts against the applied voltage that's causing the motor to spin in the first place and reduces the current flowing through the coils of the motor. Back EMF is denoted by E_b symbol.

How to calculate Back EMF Equation of DC Motor using this online calculator? To use this online calculator for Back EMF Equation of DC Motor, enter Number of Poles (n), Magnetic Flux (Φ), Number of Conductors (Z), Motor Speed (N) & Number of Parallel Paths (n_||) and hit the calculate button. Here is how the Back EMF Equation of DC Motor calculation can be explained with given input values -> 24.94334 = (4*1.187*14*135.088484097482)/(60*6).

FAQ

What is Back EMF Equation of DC Motor?

Back EMF Equation of DC motor shows that a motor has coils turning inside magnetic fields, and a coil turning inside a magnetic field induces an EMF. This EMF, known as the back EMF, acts against the applied voltage that's causing the motor to spin in the first place and reduces the current flowing through the coils of the motor and is represented as E_b = (n*Φ*Z*N)/(60*n_||) or Back EMF = (Number of Poles*Magnetic Flux*Number of Conductors*Motor Speed)/(60*Number of Parallel Paths). Number of Poles is defined as the number of poles in an electrical machine for the flux generation, Magnetic flux (Φ) is the number of magnetic field lines passing through the magnetic core of an electrical dc motor, The number of conductors is the variable we use for getting the correct number of conductors placed in the rotor of a dc motor, Motor Speed is the speed of the rotor(motor) & The Number of Parallel Paths in a DC machine refers to the number of independent paths for current to flow in the armature winding.

How to calculate Back EMF Equation of DC Motor?

Back EMF Equation of DC motor shows that a motor has coils turning inside magnetic fields, and a coil turning inside a magnetic field induces an EMF. This EMF, known as the back EMF, acts against the applied voltage that's causing the motor to spin in the first place and reduces the current flowing through the coils of the motor is calculated using Back EMF = (Number of Poles*Magnetic Flux*Number of Conductors*Motor Speed)/(60*Number of Parallel Paths). To calculate Back EMF Equation of DC Motor, you need Number of Poles (n), Magnetic Flux (Φ), Number of Conductors (Z), Motor Speed (N) & Number of Parallel Paths (n_||). With our tool, you need to enter the respective value for Number of Poles, Magnetic Flux, Number of Conductors, Motor Speed & Number of Parallel Paths and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

Home

FREE PDFs

🔍 Search