Hi edison123
The generator is 85 MVA, 0.95 PF, 13. 8 kV, 400 rpm. The core length is 62 inches, and effective length is 53 inches. The outside diameter D1 = 187 inches and the inside diameter D2 = 169 inches.
No check of the temperature of the stator and the rotor of the leased generator. But nothing was reported unusual with regard to the generator performance. You have a good point here and was missed.
The core loop test was performed on 5 steps;
Step 1: Applied voltage 477, number of turns 24, search coil 19.9 volts, loop current 17.4 amps.
Step 2: 477/13/36.5/45.7
Step 3: 476/7/58.4/108
Step 4: 470/6/75.9/212
Step 5: 570/5/103.2/554.
The duration of the test for steps 1 through 4 was 10-15 minutes. The frame temperature was about 19 C and the core reached about 22 C and back to 19.5 before the next step.
The last step (step 5) the temperature of the frame reached 20.3C after 40 minutes and the core temperture reached 31.2C. The test procedure states that the test for step 5 will last 60 minutes or until the mean core temperature reaches 10 dgrees C over the frame temperture, which happenend and discontinued the test. After the 40 minutes the supply votage was 565 volts, the supply current 620 amps, and the secondary turn voltage 102.4 volts.
An infrard camera was used during the test to detect any hot spots. The core passed the test with no hot spots.
The five points were plotted on a curve with the Ampere-turns on the Horizental axis, and the Volt/turn on the Vertical axis. It is interesting to note that only about 350 kVA was required to saturate the core and that the core temperature only increased by 10 degrees C during the 40 minute test.
Appreciate you input.
Regards, kh2