A series-connected dc motor is designed to operate with a variable load. The resistances RA and...

A series-connected dc motor is designed to operate with a variable load. The resistances RA and RF are negligible. To attain high efficiency, the motor has been designed to have very small rotational losses. For a load torque of 80 N?m , the machine runs at its maximum rated speed of 1300 rpm . Find the speed for a load torque of 350 N?m

Expert Solution

Ans)

The speed and armature current are related by the equation

where Td is torque developed

Now Ia from above equation is substituted in speed equation we get

It is given in the question that Ra is negligible we have

speed and torque are related as per this equation as remaining are constants

so

,it is given that

is the speed when load torque is 350 N-m

Manojponduru answered 2 years ago

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