#### Torque or moment or moment of force is the tendency of a force to rotate or move an object about an axis. A force is a push or pull, likewise, torque is a twist to an object. Mathematically, torque, T = F × r.

#### Let- T
_{g} = armature or gross torque ( N-m )

= ( Force × radius ) - r = radius of the armature in m
- N = speed of the armature in r.p.m. = N / 60 r.p.s

_{g}= armature or gross torque ( N-m )= ( Force × radius )

*Work done / revolution = force × distance moved per revolution*

#### The expression for voltage in dc motor is given by,

*Electrical input = electrical power equivalent to mechanical power developed + armature copper loss*

#### Mechanical power developed,

#### Since equation (1) = equation (2)

#### Hence torque of a dc motor is directly proportional to the flux/pole and armature current.

## Relation between Armature Torque (T_{a}), Shaft Torque (T_{sh}), and Loss Torque (T_{Loss}) :

#### We know,

#### The motor output =

*Loss Torque = Armature Torque - Shaft Torque*