Interlocking Two Coils

Wire two coils so they can never both be energized at once — the safety foundation for forward/reverse.

What you’re building

Steps

1. Add the parts

   Click Power Source, two Push Button NO, two Coil, and two NC Contact.

2. Label them

   Label one Coil F and the other R. Label one NC Contact F and the other R. The F NC contact is opened by coil F; the R NC contact by coil R.

3. Build rung F through R’s NC contact

   To wire, click the first terminal (it highlights), then click the second to connect them. Coil F’s path passes through the contact named R.

   Power Source L1 → Button 1 (left)

   Button 1 (right) → NC Contact R (left)

   NC Contact R (right) → Coil F A1

   Coil F A2 → Power Source N

4. Build rung R through F’s NC contact

   Mirror it: coil R’s path passes through the contact named F.

   Power Source L1 → Button 2 (left)

   Button 2 (right) → NC Contact F (left)

   NC Contact F (right) → Coil R A1

   Coil R A2 → Power Source N

5. Energize and try to break it

   Click Energize. Press button 1 — coil F energizes (and opens R’s path). Now press button 2 — coil R is locked out. Release F, then press button 2 — now R can come in. They can never both be on.