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Build Guide · Motor Control

Forward / Reverse (Buttons)

Two seal-in circuits, interlocked, driving two contactors — one wired straight, one with two legs swapped to reverse the motor.

Difficulty: AdvancedBuilds on: start/stop + interlockingLesson: read the theory →

What you’re building

L1L2/NSTOPFWDRFFREVFRR
Control circuit: shared Stop feeds two rungs. FWD energizes coil F (through R’s NC interlock); REV energizes coil R (through F’s NC interlock). Each rung has its own seal-in bracketing its own button. Only one coil can be on at a time.

…and how it reverses the motor

L1L2L3Contactor F (straight)Contactor R (L1↔L3 swapped)L1L1L2L2L3L3MUVWOnly F or R closes at a time. R reverses two legs, so the motor runs the opposite direction.
Power circuit: contactor F sends L1→U, L2→V, L3→W (straight). Contactor R swaps two legs (L1→W, L3→U), so the same motor runs the opposite direction. The control interlocks guarantee F and R never close together.

Parts to add

  • 1Power Source (3-phase)
  • 1Push Button NC (Stop)
  • 2Push Button NO (Fwd, Rev)
  • 2Coil
  • 2NO Contact (seal-ins)
  • 2NC Contact (interlocks)
  • 2Contactor
  • 1Motor

Steps

  1. Add the parts & set 3-phase

    Click the Power Source and set it to a 3-phase system (e.g. 480V 3φ). Add Push Button NC (shared Stop), two Push Button NO (Fwd, Rev), two Coil, two NO Contact (seal-ins), two NC Contact (interlocks), two Contactor, and one Motor.

  2. Label everything

    Coils F and R; seal-in NO contacts F and R; interlock NC contacts F and R; contactors F and R.

  3. Build the FORWARD rung

    To wire, click the first terminal (it highlights), then click the second to connect them. Run the shared Stop, then the Forward button, then R’s NC interlock, to coil F. Then add F’s seal-in across the Forward button.

    Power Source L1 → Stop (left)
    Stop (right) → Fwd button (left)
    Fwd button (right) → NC Contact R (left)
    NC Contact R (right) → Coil F A1
    Coil F A2 → Power Source N

  4. Add the FORWARD seal-in

    Bridge the F NO Contact across the Forward button.

    Stop→Fwd wire → F NO Contact
    F NO Contact → Fwd→interlock wire

  5. Build the REVERSE rung

    From the same Stop, run the Reverse button, then F’s NC interlock, to coil R, and add R’s seal-in across Reverse.

    Stop (right) → Rev button (left)
    Rev button (right) → NC Contact F (left)
    NC Contact F (right) → Coil R A1
    Coil R A2 → Power Source N

  6. Wire the two contactors to the motor

    Contactor F straight through; Contactor R with two legs swapped — that reversal is what spins the motor the other way.

    Contactor F → L1→T1, L2→T2, L3→T3 → Motor
    Contactor R → L1→T3, L2→T2, L3→T1 (two legs swapped) → Motor

  7. Energize and run both ways

    Click Energize. Press Forward — it seals in and runs; Reverse is locked out. Press Stop, then Reverse — it runs the other way. You can never get both contactors in at once.

  8. Note

    In this basic version, press Stop before changing direction — the interlock deliberately blocks going straight from forward to reverse.

✓ Test it

  • Forward seals in and runs; Reverse is locked out until you Stop.
  • Stop, then Reverse: motor runs the opposite direction.
  • You can never get both contactors in at once — the interlocks prevent it.
Tip: Press Stop before reversing. The interlock deliberately blocks going straight from forward to reverse in this basic version.

Open the Sandbox and build it

Follow the steps above with the trainer open in another tab.

Open the Sandbox →
← Interlocking Two CoilsNext: Forward / Reverse (Relays) →