115 KVA dry type trans hot to the touch???

[sundowner]

So I'm doing some Infraredding in a Boiler House basement - I get to the transformer and have to re-scale my camera...ambient is right around 80F, everything in the area is loadd normally - primary is pulling within spec and my sec. is to.

My question is how hot can that transformer cowling be, before I should throw up a red flag and start digging into the cause??? My trans is the run of the mill 480 Delta to 208/120Y dry type.

Thanks guys

 

[tkb]

What is the load on the transformer and what is the rise temp rating?

 

[don_resqcapt19]

The standard temperature rises for the windings of a dry type transformer are 80°C, 115°C and 150°C and that is a rise over a 40°C ambient.

While that is the winding temperature, the top of the enclosure will often be hot to the touch if there is much load on the transformer. Even with the 80°C rise, the windings of a fully loaded transformer would be operating over the boiling point of water.

 

[Ingenieur]

So I'm doing some Infraredding in a Boiler House basement - I get to the transformer and have to re-scale my camera...ambient is right around 80F, everything in the area is loadd normally - primary is pulling within spec and my sec. is to.

My question is how hot can that transformer cowling be, before I should throw up a red flag and start digging into the cause??? My trans is the run of the mill 480 Delta to 208/120Y dry type.

Thanks guys

what temp did you read?
hot to the touch could be 40C plus 40C ~ 180F which is hot to the touch but still relatively 'cool' for a 115C rated loaded xfmr

 

[big john]

Doing infrared on the exterior of a dry transformer enclosure tells you almost nothing. For that reason, it's not something we bother doing during IR surveys.

The only reason I'd flag that is if the enclosure surface was approaching the maximum nameplate temperature rise, which is well over the boiling point of water, so you'd definitely know it.