On 12 Nov, 08:41, Sparky wrote:
This cap was removed from a 70's-80's German industrial machine:

http://i37.tinypic.com/10psxg3.jpg

It has no polarity markings. One terminal is common with the metal case. Is
this always an indication of the (-) terminal?

Almost always, but ISTR reading warnings that occasionally you come
across one made for use with a negative supply rail, when the can will
be positive, so you're right to make sure.

However, in this instance I agree with other posters that the markings
indicate that the can is negative.

Chris