"Variac" Rating?
 

When I bought my used Powerstat, I was told that it was 4 amp maximum.
That may be a wild guess by the previous owner.
(It is not a standard component, was once part of a motorized
voltage regulator). The iron core is about 4 inches in diameter,
and 3 inches long. Can anyone tell me what the maximum rating is?

Thanks,
Ed Knobloch