Space heaters for Dry Type Transformers

[Shark96]

Hi, I would like to get some information related to the storage of dry type transformers. What temperature settings should be used to trip the installed space heaters. Should the temperature setting be a litte above the ambient temperature? Is there any standard for this. Please assume that the humidity is at normal levels for storage.

 

[Heaviside1925]

OP,
The goal is to prevent condensing humidity. Example, max ambient conditions 120 deg F, 100% humidity. You would want to keep the temperature at or slightly above 120 deg F because if the surface was 100 deg F, there would be a possibility of condensation. So, the temperature for the heater would be location dependent and based on max ambient conditions.

 

[waross]

All of the anti-condensation heaters that I have seen, connected, and/or repaired consist of a heater supplied at 1/2 rated voltage and energized continuously.
You want enough heat to keep the core, always above ambient temperature, whatever that may be, the core of a transformer, generator or motor is quite slow to follow changes in ambient temperature.
On a hot, humid day, a rising ambient temperature may bring the dew point above the core temperature.
When that happens, internal condensation is almost instantaneous.

--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[JJ_Roy]

Below is a clip from Virginia Transformer Corp. instructions for their dry-type transformers.

Be sure to never exceed the transformer max winding temp.