RTD on stator windings 1

[181273]

hi, I got a problem on a 6000 V, 1,5 MW generator, the RTD on phase U is broken and I´d no spare installed, I´m thinking on install a new one on the head of the winding... the winding is a wire winding....my question is if somebody knows what´s the diference on º C, of the RTD in the slot and the RTD on the head of the winding... The kind of refrigeration is IC1, this means that the air from outside come into the generator from the non drive side and go out hot from the drive end side.... I´ll mount the RTD on the drive end side.... i think the diference is on 20 º C.... thank in advance for your attention... and sorry for the bad english

 

[oftenlost]

Minco in Minneapolis, Mn USA sells small RTDs which can be placed in the cooling vents of the stator frame. I have used these utilizing insulating putty to retain in place and blocking the airflow through this air duct. This gives you the closest you can come to the coil temperature in the middle of the core

 

[aolalde]

A good guess is 20°C difference, but each machine performs according with specific construction details.
After the new RTD is installed on the coil head, run your generator with load and compare the temperature readings against the average of the others (slot embeded RTD's). That will provide you a better figure for the difference of temperature reading and a gide to set up your new alarm or trip off temperature.