Commission the reversing conveyor starter

What you will build

Work order WO-PS-401. Your site team, Commission the reversing conveyor starter.

Deccan Logistics, Hosur. Transfer conveyor TC-401 moves parcels from the sorter to the despatch bays, and the belt must run both ways to clear a jam. Its motor is 2.2 kW, 415 V, 4.6 A. The starter panel +C401 has arrived with the power circuit and the 24 V supply wired. A reversing link kit, hidden in the duct, swaps two phases for K2. The control wiring is yours.

What you will learn

• Lock out and prove dead, live then dead then live
• Land 31 control conductors from a wiring schedule
• Read the supplied PLC program and match it to your wiring
• Restore power safely, test, and run the FAT

How it goes

1. Lock out the panel at the main isolator Q1: switch OFF, apply your lock and your tag.
2. Prove it dead with the meter, live-dead-live.
3. Wire the 31 conductors of the wiring schedule. The PLC outputs get their 24 V (3L+) through the safety chain: E-STOP 11-12, then the overload's 95-96, then the safety bus X3. When the E-STOP is pressed or the overload trips, every output loses its power at once. The TRIP lamp is wired from F3 97-98 and does not use a PLC output.
4. K1 and K2 must never be in together: that shorts two phases through the reversing kit. Each coil circuit goes through the other contactor's NC contact (21-22), and the contactors are also interlocked mechanically.
5. Read the supplied PLC program. It lets a direction start only when the other is off and both contactors have been out for 2 s, so the motor is never plugged.
6. Restore power: tick the checklist, remove your tag and lock, switch Q1 ON, put the PLC in RUN.
7. Test: FWD, STOP, REV after the dwell, REV pressed while running forward, the E-STOP and an overload trip. Then run the FAT.

Parts in the panel

• Main isolator, 4-pole, 63 A

  Switches all three phases and neutral. The incoming cable lands on 1, 3, 5, 7: those terminals stay live when it is OFF.

• MCB 2-pole, 6 A, C curve: control supply

  Feeds the 24 V power supply with 230 V (L1 and N).

• MCB 3-pole, 16 A, D curve: motor circuit

  Protects the motor circuit against short circuits. The overload relay protects the motor against overload.

• Contactor FORWARD 3-pole, 9 A AC-3, coil 24 V DC, 1 NO + 1 NC aux

  Runs the belt forward. Mechanically interlocked with K2. Its NC 21-22 is in K2's coil circuit and its NO 13-14 tells the PLC it pulled in.

• Contactor REVERSE 3-pole, 9 A AC-3, coil 24 V DC, 1 NO + 1 NC aux

  Runs the belt in reverse: the reversing link kit feeds it with L1 and L3 swapped. Mechanically interlocked with K1. Its NC 21-22 is in K1's coil circuit.

• Thermal overload relay, 5.5-8 A

  Trips on sustained overcurrent. 95-96 (NC) opens and 97-98 (NO) closes. Blue button: reset.

• Power supply 230 V AC to 24 V DC, 5 A

  Its 0 V (−) is bonded to PE at the factory, so 0 V and earth are the same potential.

• PLC: compact CPU, 8 DI / 6 DQ, 24 V DC

  Inputs I0.0-I0.7 are PNP: 24 V on the terminal turns the input on, with 1M at 0 V. Outputs Q0.0-Q0.5 source 24 V from 3L+, which here comes through the safety chain.

• Terminal strip X2: 24 V DC distribution

  Positions 1-6 are bridged +24 V, 7-12 are bridged 0 V. Top and bottom of each position are the same point.

• Terminal strip X3: safety bus, 3 terminals bridged

  The 24 V that has passed the E-STOP and the overload contact. One goes to the outputs' 3L+, one to the PLC input that watches it.

• Terminal strip X1: motor

  The motor cable from the plant lands here.

• PE bar

  Protective earth, bonded to the incoming supply's earth.

• Push button FORWARD, green, 1 NO

• Push button REVERSE, green, 1 NO

• Push button STOP, red, 1 NC

• Emergency stop, 2 NC, twist to release

  Contact 11-12 is in the safety chain that powers the outputs; 21-22 tells the PLC.

• Pilot lamp green 24 V: RUNNING FORWARD

• Pilot lamp green 24 V: RUNNING IN REVERSE

• Pilot lamp amber 24 V: OVERLOAD TRIPPED (hardwired)

• Motor 3-phase 2.2 kW, 415 V, 4.6 A, driving transfer conveyor TC-401

Questions

Is it free?

Yes. The lab is free to use with a free account. There is nothing to buy to open this scenario.

Do I need to install anything?

No. It runs in your browser with a 3D panel, a circuit drawing, a meter and a PLC.

What will I do in Panel Lab 4?

You wire a control panel, then check your work against an acceptance test.

How long does it take?

Plan for one sitting. You can stop and come back.

Do I need experience?

No. Each work order says what to do step by step, and hints are there if you get stuck.