🔍 Key Concepts

• Identify which auxiliary contacts are normally closed (NC) and which are normally open (NO) in the control circuit above the contactor coils. • Trace the control circuit path to the 1S coil and then to the R coil to see what happens if one is already energized. • Note how the 2S timed contacts (TO and TC) behave during start and after the time delay and whether their state alone could block both coils from being energized together.

💭 Think About

• If 1S is already pulled in, what happens to the control power path that would try to energize R? Which contact actually opens that path? • If R is already pulled in, what happens to the path that would try to energize 1S? Which contact in the schematic changes state to prevent this? • Do the 2S timed contacts still provide interlocking once the timer has finished its function, or are they mainly for changing from starting to running connections?

✅ Before You Answer

• Verify which auxiliary contacts labeled 1S and R in the top control circuit are drawn as normally closed and which as normally open. • Confirm whether both 1S and R coils could ever have a closed path to power at the same time, based on the normal (de‑energized) state of the drawing. • Check that mechanical interlock is shown between 1S and R, but ask yourself what electrical feature, visible in the ladder diagram, independently prevents both from energizing together.