when the speed of a dc motor increase the armature current

A motor has an armature resistance of 4 ohm. On a 240 V supply and a light load, the motor speed is 200 rpm and the armature current is 5 A Calculate the motor speed at a full load. When armature current is 20 A.

The ratio of speeds of a motor boat to that of the current of water is 36:5. The motor along with the current in 5 hours 10 minutes.The time required to come back of motor boat is equal to

Write any one use of a d.c motor.

How can the speed of rotation of the armature coil of an electric motor be increased ?

The current in the armature of dc motor is the maximum when the motor is :

The back e.m.f. of a d.c. motor delivering 5 kW of mechanical power is 200 v, when operating on a 220 V line. Determine the armatre current and the motor resistsance.

(a) Suppose the windings og the armature in the d.c. motor or Example 4 connot tolerate a current of more than 20 amp. WhaT do you think will happen if the armature gets jammed and cannot rotate when the motor is connected to the supply ? (b) If the supply connection of the d.c. motor in Ex. are removed and the motor is used as a generated by connecting the shaft of its armature to an external mechanical rotor of speed 3000 r.p.m., how much e.m.f. will be generated ?