Message Board Thread - "Please comment this thermogram image"

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Please comment this thermogram image fazlye 4/7/2008
this thermogram were taken quite sometime ago, and until to date i am still confused to what am i seing in the image...dear guys please comment!

some more... can u guys tell me the acceptable temperature range for electrical, mechanical apparatus.

thanks
 
Re:Please comment this thermogram image Gary Orlove 4/7/2008
I have adjusted the image to aid interpretation. What do you think web visitors?
 
Re:Please comment this thermogram image Toolman 4/7/2008
Gary,

Your adjusted image helps.

This image appears to be of two side by side 3 phase relays or electromagnetic motor starters. While the unit on the left is running warmer than the one on the right, there are no obvious significant temperature differences between it's phases and no "red flag" hot spots apparent. The warmest spot on the image appears to be in the body of the device, which would be consistent with the location of the coil, and the temperatures indicated, while maybe a hair on the warm side, are not inconsistent with normal operation of this general type of equipment. It's possible that there could be an internal contact resistance or load related issue with the unit of the left, but without additional information such as ambient temperature, comparative equipment load, specific device information, etc. IMHO it's not possible to go much further than that.
 
Re:Please comment this thermogram image Top Gun 4/7/2008
I agree in most part with Toolman. I see three similar three-phase devices, the image clips the third one off at the right. There also is a timing issue involved. All three may have the exact load characteristics, and it is possible that the left-hand item may have been running for some time and MAY have just switched off. The center device MAY have been energized for a short time and hasn't had enough time to warm up to normal operating characteristics, i.e. it is not in thermal equilibrium, and is not ready for thermal evaluation. The item on the right -- its coil is energized but the load is low or the current is not ample enough to heat the conductors, an overcurrent device has opened and shut the current off, or the utilization device is not using as much energy, or drawing much less load. I see set-ups like this many times in grocery stores. Amp readings would provide truly valuable information on this one, and a short history of recent events would clarify "what's going on here".
 
Re:Please comment this thermogram image fazlye 4/7/2008
Guys, thank you for the comments, however this is some amps reading for the "left One" red-43A, blue-45A, yellow-47A, previously there is no fault ever recorded for this equipments. However this equipment are hook-up to a 3phase water pump. pumps are running on 12 hours timer. hope it will help u guys. this setup is taken from one of the highest twin tower building in the world. ambient temperature is 34 degree Celcius. Trefl= 33.4 degree Celcius. lastly the equipment is actually a 3 phase maggnetic contactor with rating of 100Ampere.
 
Re:Please comment this thermogram image Toolman 4/7/2008
Fazlye,

Thanks for the additional information.

The indicated temperatures of the individual phases appear to be less than 10 deg C above ambient and within a degree or two of each other, and as such do not appear to be an imminent problem.

What concerns me more is the load imbalance between phases. For good motor efficiency, NEMA recommends that phase imbalance be kept to <1% of the average. The measurements you provided reflect an imbalance of approx. 4%, which will result in an increase of the motor temperature rise of approximately 16%, and a decrease in both efficiency and performance.

A common cause of this is a difference in the phase voltages, usually due to unevenly balanced single phase loads. Have an electrician check the phase voltages, and if there is one, it can often be corrected by balancing the single phase loads between phases. If you don't find a difference in phase voltages, then you need to take a look at the motor.

Sorry for the long post - hope you find this useful.
 
Re:Please comment this thermogram image fazlye 4/8/2008
Dear Toolman and all.

Thank you very much for the explanation. Now we know what to do.

Thank you again.
 
Re:Please comment this thermogram image photohasse 4/10/2008
I agree with Toolman about the higher temperature inside the relay.
I would if possibly check the realy from a different angle and see if the temparaure pattern will give some hint about bad internal contacting area.
The high temperature on the right outside of the relay does not make sense.
 
Re:Please comment this thermogram image jvoitl 4/10/2008
The hot spot on the right outside of the relay makes perfect sense. It is from the coil inside the relay that operates the relay and will always show up warm when the relay is energized.
 
Re:Please comment this thermogram image Raul G. 5/9/2008
jvoitl wrote:
spot on the right outside of the relay makes perfect sense. It is from the coil inside the relay that operates the relay and will always show up warm when the relay is energized.
Hello to everybody. I can see in the thermogram that the emissivity is 0.9, I have read and I have heard for thermographers trainners that for switchboard we can use E= 0.75 - 0.78, because the switchboards have differents components with differents emissivities, and for that reason they considered an average. If We considerated that, so the temperature would be more than 51.9ÂșC. Another thing that I see is reflecting zones, for example, We can see colder zones in middle of the cables.

Regards.
 
Re:Please comment this thermogram image Laland 5/11/2008
The phase voltages are unbalance, can you check for a motor circuit analysis to determine what causes the unbalance voltage. Check for power quality.
 
Re:Please comment this thermogram image mlehman 5/11/2008
Being a electrician in a indutrial plant, the small difference in the amps is not a worry to me. It looks like there is some reflection happening. If this is an older motor starter take it apart and check the contacts. If its a newer CHEAPER one than change it. I would say that it has worn over time and its not pulling in evenly.
Matman
 
Re:Please comment this thermogram image Apprentice 5/19/2008
Please excuse my inexperience Level one newby...Zero degree thermogram angle seems to be a factor,though ambient operating temperature is a want,its not always achievable due to internal resistance.And uneven conduction is clear,if it were conduction from the apparatise and not background hardwares exitant radiation.e=.9,very wrong.do an e test prior to scanning and as my mentors would like to see a piece of allu bubble to coorectly see Trefl,measure and compensate.old,new.oxidized or not.information is critical when reading any thermogram in any situation...as for the image.no comment
 
Re:Please comment this thermogram image Apprentice 5/19/2008
Conduction is very important.Safety first,lets not cuase conduction between ourselves and the hardware we scan...
 
Re:Please comment this thermogram image Carl M 5/26/2008
Toolman wrote:


Thanks for the additional information.

The indicated temperatures of the individual phases appear to be less than 10 deg C above ambient and within a degree or two of each other, and as such do not appear to be an imminent problem.

What concerns me more is the load imbalance between phases. For good motor efficiency, NEMA recommends that phase imbalance be kept to <1% of the average. The measurements you provided reflect an imbalance of approx. 4%, which will result in an increase of the motor temperature rise of approximately 16%, and a decrease in both efficiency and performance.

A common cause of this is a difference in the phase voltages, usually due to unevenly balanced single phase loads. Have an electrician check the phase voltages, and if there is one, it can often be corrected by balancing the single phase loads between phases. If you don't find a difference in phase voltages, then you need to take a look at the motor.

Sorry for the long post - hope you find this useful.
Correction to the NEMA quote. EASA actually mentions this and it is regarding a difference in live VOLTAGE that is so critical, not current (amps). The current differences in this model are acceptable. I see a motor contactor in the image operating under normal conditions.

Carl M.
 
Re:Please comment this thermogram image manuel-thermoimagen 5/26/2008
fazlye wrote:
ermogram were taken quite sometime ago, and until to date i am still confused to what am i seing in the image...dear guys please comment!

some more... can u guys tell me the acceptable temperature range for electrical, mechanical apparatus.

thanks
Hi there!!

first at all, i will define what i want to use image for, i mean, if pourpose is detect ELECTRICAL OPORTUNITIES, then i can use QUALITATIVE analisys, where, no matter temperature i will have some components to work on, where to go hands on.

In the other hand, if i would keep image for future reference, then i will choose the closes emisivity value or average in order to write it down someplace at cabinet for the next inspection and keep logging images.

my two cents.

regards.
roberto.cruz@thermoimagen.com
 


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