TEWAC stands for “Totally Enclosed Water to Air Cooled” and relates normally to the provision of motor stator cooling. The stator is generating electricity and thus the more general name “Generator Cooler” is often used.
To be clear:
TEWAC will refer to the cooler itself AND the enclosure
Generator cooler can refer to the above, but also, just the insert within the enclosure
Vestas manufactures all types, as replacements or as new requirements for original equipment.