Help identifying dead electro. cap polarity?

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?
The base has molded terminal locations numbered 1-4, two of which are empty:
<
http://i36.tinypic.com/e6x542.jpg
Markings on the side are:
B41111-B7108-T 1000uF 40V- GERMANY GPF DIN 41332 06.78
I find a few references to a Siemens part that is similar:
<http://www.screenghost.com/shop/show.asp?IDt#
but no datasheet can I find. Can someone more resourceful than I find one?
I cut open one of these caps. It is paper & foil (or so it seems) spiral wrap construction. Can polarity be determined by internal construction? Is the center terminal always one pole (ie, always +)?
Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Sparky"

** Bullshit.

** Yep.

** Are you totally blind ????
The usual cause applies ?????
FYI:
The markings are clearly 1, 2 and 3 with the fourth a NEGATIVE sign !!!!!!!!!!!!!
Is not the negative sign *right next* to the pin linked to the case ?????
.... Phil
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

To me they look like "1" (not a "-"), "2", "3", and a really weird "4".

But with your help along with the one pin (yes, it's the (-) one) in common with the case pretty much confirms polarity.
Thanks!
Nighty-night! Lights out!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"notme"

** Nonsense.
The stroke on the " 1" has been made longer to avoid confusion with the " - " sign.
.... Phil
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Ahh but it's german. They make the 1 with that little hat. And then when they make a 7 they always add a cross through the middle... so as not to confuse it with the one.
George H.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
In message

The Germans (and those in many other Continental European countries) certainly do that when WRITING the number 7. However, I can't recall ever seeing it on a PRINTED 7. This is (of course) because they start writing a 1 (one) with a long slanted up-stroke, followed by a vertical down-stroke. As such, it's not unlike an 'artistically' written 7. The addition of a horizontal stroke through the vertical down-stroke of the 7 prevents it from being confused with a 1. With a printed 7, the top stroke is definitely horizontal, and there is no confusion.
Most non-Europeans write a 1 (one) as a single vertical down-stroke, so there is no possibility of confusion between a 1 and a 7. However, if you decide to embellish a 1 with the short slanted up-stroke at the top and the foot at the bottom, you have to be careful that it cannot be confused with a 2.
--
Ian

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Phil Allison wrote:

For modern capacitors, yes, *BUT* there were some chassis-mounted caps with POSITIVE (outside) cans/cases.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

AFAIK Germans always write a ONE with a tag ( opposite 2) and a 7 with a tag through it that makes it look like a lower case t. So I suggest the - really is MINUS.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
TTman Inscribed thus:

I agree ! That is how I read it.
--
Best Regards:
Baron.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Me, I'd guess the terminal marked with the '-' is negative, but that's just my warped thinking.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sparky schrieb:

<http://www.bilder-hochladen.net/files/12b4-4t-jpg.html
HTH
Reinhard (native German ;-) )
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sparky wrote:

How is it wired in the circuit? When in doubt, this is what I look at. You can also substitute it with an AC rated cap and just measure the voltage across it to find out which way around it should be.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.