Changing Contacts on a B/W Controls 1500 Series Relay and Converting between N.O. and N.C.

The contacts in a B/W Controls 1500 Series relay can easily be changed or converted between normally-open (N.O.) and normally-closed (N.C.) in the field. In this guide, we will convert a B/W Controls 1500-C relay (with two normally-open contacts) to a 1500-D relay, by converting one

What We'll Need

  • Small flat-head screwdriver
  • Optional:
    • Medium-size flat-head screwdriver
    • 3/16 inch nut driver


  1. To begin, we'll take the four cover screws out. This can be done with a flathead screwdriver or a 3/16" nut driver.
    Step 1
  2. Before we remove the cover, be aware of the small return spring inside that will become loose when we take the cover off.
    Step 2Spring
  3. Remove the cover and the armature. Now you can see the contacts.
  4. To convert a contact between N.O. and N.C., remove each side of the contacts from the relay, and swap them, so that they are now facing in opposite directions when compared to before. See the diagram for reference.
  5. Now reverse the corresponding contact on the armature.
    • If the contacts are worn, you can also replace them with a new contact kit.
    Step 5
  6. Replace the armature, and place the return spring in the upper channel.
    Step 6
  7. Replace the cover, making sure to fit the tab in the groove above the return spring.
    Step 2
  8. Replace the cover screws, and verify that the relay operates in the correct configuration.
  9. Mark the nameplate to keep track of any changes in configuration we have made.
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