Which of the following methods does not take into account the maximum temperature rise under variable load conditions ?
A. Equivalent power method
B. Equivalent current method
C. Method of average losses
D. Equivalent torque method
The time taken by the machine to attain 0.632 of its final steady temperature rise is called_____________?
A. Heating time constant
B. Cooling time constant
C. Either a. or b.
D. None of the above
Direct water cooling of rotor winding presents_____________?
A. No mechanical difficulties
B. Lesser mechanical difficulties
C. Greater mechanical difficulties
D. None of the above
Machines cooled by direct cooling method may be called_____________?
A. “supercharged”
B. “inner cooled”
C. “conductor cooled”
D. Any of the above
Which of the following is an advantage of hydrogen cooling ?
A. increase in efficiency
B. increase in ratings
C. increase in life
D. smaller size of coolers