What happens to motor speed when armature resistance is increased?

Armature control method That means, when supply voltage V and the armature resistance Ra are kept constant, then the speed is directly proportional to armature current Ia. Thus, if we add resistance in series with the armature, Ia decreases and, hence, the speed also decreases.

Why does the armature resistance increase when the motor is running?

Why does armature current increase when load on the DC motor increase? When the load increases the motor slows down. This reduces the counter EMF. This allows a higher current to flow.

How does resistance affect motor speed?

As we increase the armature Resistance, the drop across armature increases, which cause in decrease in the speed. As we add external Resistance in Rotor, the field current will decrease which causes decrease in Flux per pole (phi) , hence speed of the motor increases.

How can the resistance of a motor be increased?

The only change in motor resistance would be an increase from IR heating of the wire. The only change in inductance would be if the voltage gets high enough to saturate the magnetics, which would cause a reduction in the inductance.

What happens when armature current increases?

With increased armature current maximum speed, could be controlled up to rated speed, from zero speed as V= Eb+IaRa, where V the rated voltage and Ia the rated armature current, Eb back EMF(Eb=OZNP/60A) produced at rated field current (If) and speed(N).

Why armature current decreases as the motor accelerates?

A DC motor is a device which converts electrical energy such as voltage and current into mechanical energy like speed. (3) we can say, speed is inversely proportional to armature current. Thus, when the speed of the dc motor is increased, the armature current will decrease.

What is the resistance of a motor?

Earth Continuity and Resistance Test With a multimeter, measure the resistance between motor frame (body) and earth. A good motor should read less than 0.5 ohms. Any value greater 0.5 ohms indicate trouble with the motor.

Why armature rheostat is kept in maximum position?

At the time of starting of motor, the armature resistance is kept at maximum position to control and reduce the high starting current and field rheostat atminimum position to ensure that speed does not go beyond rated value and to have high starting torque.