Block stu transformers 24v block stu 100 24 the block stu 100va transformer 24v is a low inrush current control safety or isolation current transformer with screw connection terminals designed with a very good switch on behaviour thanks to reduced starting currents plus high performance for the volume thanks to compact design this high quality tranfsormer also has excellent corrosion protection and low noise thanks to blockimpex vacuum impregnation block stu 100 24 100va transformer 24