With reference to DC motors, state TRUE/FALSE for the following statements.

1. The difference between armature torque and shaft torque is known as lost torque.

2. Increase in flux would decrease the torque.

Torque in DC motor:

• In DC motors, the actual torque available at the shaft for doing useful mechanical work is known as Shaft Torque.
• The complete electromagnetic torque developed in the armature is not available on the shaft.
• This is so because a part of it is lost to overcome the iron and mechanical (friction and windage) losses.
• Therefore, shaft torque is somewhat less than the torque developed in the armature.
• Thus, the difference between the armature torque and the shaft torque is known as the lost torque.
   

The net developed torque in a DC motor is given by:

T = kϕI_a

Where, T = Developed torque

ϕ = Armature flux

I_a = Armature current

Therefore, torque is directly proportional to the armature flux and current.

So, by increasing flux or current, the torque also increases.