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Back EMF of DC Generator Formula

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Back EMF is developed when current flows through the armature, it generates a magnetic field that interacts with the field produced by the field winding to produce a torque. Check FAQs

E b = V o - (I a \cdot R a)

E_b - Back EMF?V_o - Output Voltage?I_a - Armature Current?R_a - Armature Resistance?

Back EMF of DC Generator Example

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Here is how the Back EMF of DC Generator equation looks like with Values.

Here is how the Back EMF of DC Generator equation looks like with Units.

Here is how the Back EMF of DC Generator equation looks like.

90 = 150 - (0.75 \cdot 80)

90V = 150V - (0.75A \cdot 80Ω)

90 = 150 - (0.75 \cdot 80)

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Back EMF of DC Generator Solution

Follow our step by step solution on how to calculate Back EMF of DC Generator?

FIRST Step Consider the formula

E b = V o - (I a \cdot R a)

Next Step Substitute values of Variables

∴

E b = 150V - (0.75A \cdot 80Ω)

Next Step Prepare to Evaluate

∴

E b = 150 - (0.75 \cdot 80)

LAST Step Evaluate

∴

E b = 90V

Back EMF of DC Generator Formula Elements

Variables

Back EMF

Back EMF is developed when current flows through the armature, it generates a magnetic field that interacts with the field produced by the field winding to produce a torque.

Symbol: E_b

Measurement: Electric PotentialUnit: V

Note: Value can be positive or negative.

Formulas to find Back EMF

Output Voltage

Output Voltage is the electrical potential difference between the two terminals of the dc machine. Output Voltage is also called the Terminal Voltage.

Symbol: V_o

Measurement: Electric PotentialUnit: V

Note: Value can be positive or negative.

Formulas to find Output Voltage

Armature Current

Armature Current is defined as the current developed in the armature of an electrical DC generator due to movement of rotor.

Symbol: I_a

Measurement: Electric CurrentUnit: A

Note: Value can be positive or negative.

Formulas to find Armature Current

Armature Resistance

Armature Resistance is the ohmic resistance of the copper winding wires plus the brush resistance in a dc machine.

Symbol: R_a

Measurement: Electric ResistanceUnit: Ω

Note: Value should be greater than 0.

Formulas to find Armature Resistance

Other formulas in DC Machine Characterstics category

Go Design Constant of DC Machine

K f = \frac{Z \cdot P}{2 \cdot π \cdot n ll}

Go Angular Speed of DC Machine using Kf

ω s = \frac{V a}{K f \cdot Φ \cdot I a}

Go Back Pitch for DC Machine

Y b = (\frac{2 \cdot n slot}{P}) + 1

Go Front Pitch for DC Machine

Y F = (\frac{2 \cdot n slot}{P}) - 1

How to Evaluate Back EMF of DC Generator?

Back EMF of DC Generator evaluator uses Back EMF = Output Voltage-(Armature Current*Armature Resistance) to evaluate the Back EMF, The Back EMF of DC Generator is defined as the opposition offered the supply voltage. The supply voltage induces the current in the coil which rotates the armature. The electrical work required by the motor for causing the current against the back emf is converted into mechanical energy. Back EMF is denoted by E_b symbol.

How to evaluate Back EMF of DC Generator using this online evaluator? To use this online evaluator for Back EMF of DC Generator, enter Output Voltage (V_o), Armature Current (I_a) & Armature Resistance (R_a) and hit the calculate button.

FAQs on Back EMF of DC Generator

What is the formula to find Back EMF of DC Generator?

The formula of Back EMF of DC Generator is expressed as Back EMF = Output Voltage-(Armature Current*Armature Resistance). Here is an example- 90 = 150-(0.75*80).

How to calculate Back EMF of DC Generator?

With Output Voltage (V_o), Armature Current (I_a) & Armature Resistance (R_a) we can find Back EMF of DC Generator using the formula - Back EMF = Output Voltage-(Armature Current*Armature Resistance).

Can the Back EMF of DC Generator be negative?

Yes, the Back EMF of DC Generator, measured in Electric Potential can be negative.

Which unit is used to measure Back EMF of DC Generator?

Back EMF of DC Generator is usually measured using the Volt[V] for Electric Potential. Millivolt[V], Microvolt[V], Nanovolt[V] are the few other units in which Back EMF of DC Generator can be measured.

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Back EMF of DC Generator Formula

Back EMF of DC Generator Example

Back EMF of DC Generator Solution

Back EMF of DC Generator Formula Elements

Other formulas in DC Machine Characterstics category

How to Evaluate Back EMF of DC Generator?

FAQs on Back EMF of DC Generator

Variable Name