Which contacts are closed in the RUN mode?

• A. 2 & 3
• B. 1 & 2
• C. 1 & 3
• D. 1 & 4

Answer: (B)

In RUN mode the control coil is energized, and the state of the relay contacts follows that energization. Normally open contacts close when the coil is energized, while normally closed contacts open. So, the contacts that end up closed in RUN are the NO contacts that are wired into the RUN circuit. This is why the option showing the two contacts that are closed when the RUN coil is energized is the correct one—the RUN condition activates those NO contacts to complete the running circuit. The other possibilities would require NC contacts to remain closed or would involve paths not driven by the RUN coil, which doesn't happen when the device is in RUN.