how exactly this switch works? does it close the contacts when green is pushed and keeps it closed until red is pushed?

enter image description here

  • 2
    \$\begingroup\$ Datasheet says? \$\endgroup\$ Sep 11, 2014 at 1:04
  • \$\begingroup\$ I don't have it. \$\endgroup\$
    – dvdmn
    Sep 11, 2014 at 1:08
  • 1
    \$\begingroup\$ Why the bleep not? \$\endgroup\$ Sep 11, 2014 at 1:09
  • \$\begingroup\$ You are showing pictures of two different switches. Which one are you interested in? \$\endgroup\$ Sep 11, 2014 at 2:24
  • \$\begingroup\$ 1st one was same type with a case, 2nd without case. I found pictures in an article and there was no info about this switch other than its name. Also that article states them as "same thing". \$\endgroup\$
    – dvdmn
    Sep 11, 2014 at 4:34

1 Answer 1


Based on a Google image search, I believe that this part is APBB-22N. A Google search on that part number show pages for a bunch of importers. Although I couldn't find a proper datasheet, the descriptions for this part on the importer pages all say "Momentary." One of the pages shows this schematic:

schematic for start/stop PBs

This makes sense. Industrial Start/Stop pushbuttons are usually momentary. The reason for this is that you do not power machinery directly from the pushbuttons; instead, you would have the start button latch in the circuit for a motor starter/contactor coil, and the stop button would break the coil circuit. (Or, you wire both buttons into PLC inputs and do the latching there.)

To answer your question, on this switch I believe there are separate contacts for the green start button and the red stop button. The contacts for the green start button are Normally-Open (terminals 13 & 14), and the contacts for the red stop button are Normally-Closed (terminals 21 & 22). Both are momentary pushbuttons. There are also terminals for the light between the buttons (terminals X1 & X2).


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