# If the motor is operating at full load and if its variable resistance Radj is increased to 250…

5-3 If the motor is operating at full load and if its variable resistance Radj is increased to 250 ?,

what is the new speed of the motor? Compare the full-load speed of the motor with Radj = 175 ? to

the full-load speed with Radj = 250 ?. (Assume no armature reaction, as in the previous problem.)

[Answer: 1061 r/min]

5-4 Assume that the motor is operating at full load and that the variable resistor Radj is again 175

?. If the armature reaction is 1200 A-turns at full load, what is the speed of the motor? How does it

compare to the result for Problem 5-2?

[Answer: 1447 r/min]

5-5 If Radj can be adjusted from 100 to 400 ?, what are the maximum and minimum no-load

speeds possible with this motor?

[Answer: 1004 r/min, 1447 r/min]

5-6 What isthe starting current of this machine if it isstarted by connecting it directly to the power

supply VT? How does this starting current compare to the full-load current of the motor?

[Answer: 600 A, The starting current is 10.9 times greater than the full-load current]

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