Dry Type Xfrmr in 95% RH application

[HomeMadeSin]

Is there any special considerations to take into account for using a small transformer to step-up 208 3 phase to 230 3 phase in a very humid environment...as in 95% or so relative humidity? It would either be an 18 kVA for powering a group of pumps or 75 kVA for powering all of the pumps (21 total). Imagine a large aquatium and fish shop in Atlanta (hot).

 

[dpc]

Encapsulated cores transformers are available up through about 27 kVA. These would be fine to use in a humid environment. For your application, you need a autotransformer connection to boost the 208V to 230V. This would actually be quite a small transfomer if you use an autotransformer connection, since the voltage difference is small.

Check with GE, Cutler-Hammer and Square D. They can probably help you out.

 

[busbar]

On dpc’s suggestion, if a boost to 229V from 208V is adequate, two 120:24V 5kVA transformers in an open-delta arrangement could do it for a 75kVA load.

An issue may be enclosure susceptibility to corrosion; requiring units not “off-the-shelf.”