Motor temperature monitoring

[ChuckR]

Please, what experiences have you had using PLC analog inputs with bearing and winding RTD temperature sensors?

Specifically Allen-Bradley MicroLogix 1500 and RTD input module. RTD's are PT-100 , 2 per winding, 1 each at bearings, 460V motor.

Is noise going to be a problem when motor runs?

My only previous experience was with a 4160v motor and thermmocouples, when motor was operating temperature readings went all to h---.

Thank you kind sirs.

 

[Tom Jenkins]

I haven't done it with Allen Bradley MicroLogix, but I have on SLC and AutomationDirect.com. These were 480 Volt motors, including a VFD controlled system, and noise on the RTD modules was not a problem. Note that RTDs are inherently less susceptible to noise than thermocouples.

 

[rogerhollingsworth]

I also haven't done it with Allen Bradley MicroLogix, but I have on Allen-Bradley enhanced processors. These were 480 Volt motors, pump bearings and large generators(6600 volt, 25Hz) and never had a problem with noise.

Roger

 

[SAK-CO TECH]

I also have run RTD's and their respective wiring in very close proximity to 480 vac on tag lines lying on top of each other without any problems.

As Tom has stated, thermocouple's can give you trouble with noise, hence the reason I stay with RTD's where possible.

Regards,
Chris

 

[shooter]

have two wires inside motor good twisted until out of danger zone.
as temp is not very precise this will be enough.
if needed more use 4 wire technique all twisted (ftp cable is good for this.

 

[TGRAB]

I've used RTD's on motor winding temps on 4160V motors and during starting inrush got bad readings on temperature. I just disable the alarms while starting to eliminate any alarms/interlocks.