Small variac transformers (03/09/12)

Two small potted variable transformers I got ages ago. One is a normal autotransformer, with a 0-220V output, but the other has an isolated low-voltage secondary winding giving 0-15V output. I've never seen one like this before. Both very old, but still work fine. The low-voltage one includes an on/off switch in the fully ACW position.

They appear to have been made by REO, and their website still lists similar-looking transformers: (dig under the "Variable transformers" section).

Normal (0-220V output):

Stamped "Geprüft Nr. 10 3 NOV 1966"

Type RRTW Nr. W2922
Leistg. 0-360VA P00
Netzspg. 220V Hz 50-60
Nennspg. 0-220V 1.65A

Low-voltage (0-15V output):

Stamped "Geprüft Nr. 8 05 SEP 1970"

Type RRTGW Nr. Y39029
Leistg. 0-135VA P00
Netzspg. 220V Hz 50-60
Nennspg. 0-15V 9A