Markvguy, reur 18-Dec-06, 6:53 pm... thnx, it certainly cleared things up:
So, as I now understand it, the speed-amp data was that of the motor, while driving the torque converter, with the converter driving the gt rotor. Hence, during acceleration of the gt rotor, the motor is running at about nominal speed except at the higher slip-frequency caused by operating the motor in an overloaded condition for several minutes!
In answer to your specific question... everything I stated (re: rotor damage) is still applicable! Only now, the "growl" or noise I alluded to earlier will be heard at slip-frequency. The "growler" instrument you referred to has nothing to do with the "growling noise" I mentioned. The scope trace of motor current will still show the effect of rotor damage. In fact, if it can be heard, then it can be "observed!" A single-tube fluorescent lamp will flash at twice line frequency. When used to illuminate the motor shaft, then, the loudness of the "noise" emanating from the motor will be synchronized to the slowly rolling image of the motor shaft.
The instrument I alluded to was not the growler of old, but a modern version of the fluoresnt lamp technique. Instead, it uses a clamp-on current measurement to indicate what I described! The one I am best familiar with is manufactured by a Canadian Company... Iris Power Engineering Inc.
An aside, all of the torques developed by the motor, i.e., break-away, pull-up, pull-out, and max, together with their associated current magnitudes, have nothing to do with the driven-load! They are dependent only on the motor's electrical parameters!
Regards,
Phil Corso, PE {Boca Raton, FL, USA}
[[email protected]] ([email protected])
So, as I now understand it, the speed-amp data was that of the motor, while driving the torque converter, with the converter driving the gt rotor. Hence, during acceleration of the gt rotor, the motor is running at about nominal speed except at the higher slip-frequency caused by operating the motor in an overloaded condition for several minutes!
In answer to your specific question... everything I stated (re: rotor damage) is still applicable! Only now, the "growl" or noise I alluded to earlier will be heard at slip-frequency. The "growler" instrument you referred to has nothing to do with the "growling noise" I mentioned. The scope trace of motor current will still show the effect of rotor damage. In fact, if it can be heard, then it can be "observed!" A single-tube fluorescent lamp will flash at twice line frequency. When used to illuminate the motor shaft, then, the loudness of the "noise" emanating from the motor will be synchronized to the slowly rolling image of the motor shaft.
The instrument I alluded to was not the growler of old, but a modern version of the fluoresnt lamp technique. Instead, it uses a clamp-on current measurement to indicate what I described! The one I am best familiar with is manufactured by a Canadian Company... Iris Power Engineering Inc.
An aside, all of the torques developed by the motor, i.e., break-away, pull-up, pull-out, and max, together with their associated current magnitudes, have nothing to do with the driven-load! They are dependent only on the motor's electrical parameters!
Regards,
Phil Corso, PE {Boca Raton, FL, USA}
[[email protected]] ([email protected])