Armature Current Calculator

Armature Current Calculator

In the field of electrical engineering, armature current is an essential concern, particularly when it comes to working with 

  • Electric Motors and 
  • Generators 


When it comes to electric machines, the component that is responsible for carrying alternating current is known as the armature current. 

For this reason, the first step in determining the relationship between armature current & current is to make use of the relationship between torque and speed. 

Following that, take into consideration the connection between torque & armature current.

The current that is flowing through the armature winding of a machine is represented by this voltage, which is an essential factor in determining how well the machine performs under a variety of various operating conditions.

When it comes to examining the efficiency, torque, & speed of electric motors, as well as the voltage that is generated in generators, having a solid understanding of armature current is absolutely necessary.

The calculation of armature current, denoted as Ia(A) in amperes, involves dividing the difference between the applied voltage, denoted as V(V) in volts, and the electromotive force, denoted as E(V) in volts, by the armature resistance, that is Ra(Ω) in ohms.

Ia (A) = V (V) – E (V) / Ra (Ω)


Ia (A) represents the armature current.

V (V) represents voltage in volts, V.

E (V) represents electromotive force in volts (or) V.

Ra (Ω) represents armature resistance in ohms (Ω).

The armature current, denoted by A, is equal to Ia (A).

Calculate the armature current for a motor with 240 volts applied voltage, 220 volts back emf, and 0.5 ohms armature resistance


V (V) = 240 V

E (V) = 220 V

Ra (Ω) = 0.5 Ω


Armature Current

Ia (A) = V (V) – E (V) / Ra (Ω)


Ia (A) = 240 – 220 / 0.5

Ia (A) = 20 / 0.5

Ia (A) = 40A

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