Power + control together
Trace 400 V main power and 24 V control instead of learning each half in isolation.
Motor-control circuit simulator
Operate the starter. Trace the current. Find the fault.
A complete browser workbench for DOL, forward/reverse, jog, Hand/Off/Auto and star-delta circuits—with guided commissioning, recognizable components, live power paths and a virtual multimeter.
Responsive touch controls · momentary buttons work while held · safe training model
Quick answer: a motor-control simulator should show both the low-voltage decision circuit and the three-phase power path. This workbench combines recognizable starter hardware, live contacts, motor behaviour, exact meter nodes, inserted faults and commissioning checks.
DOL starter assemblyKM1 closed
1450 rpm
8.2 A
RUNNING
Pro commissioning path4 scenarios · saved progress · PLC/HMI handoff
The guide is public. The working lab is Pro.
Use this page to understand the equipment, workflow and terminology. Sign in to the Pro path to operate the full physics model, complete commissioning evidence, inject faults and continue into a prepared PLC–HMI Sandbox project.
- 01
DOL three-wire starter
Foundation
- 02
Forward / reverse starter
Interlocking
- 03
Run / jog control
Machine motion
- 04
Hand / Off / Auto pump
Process demand
- 05
Star–delta sequence
Advanced
From schematic to evidence
Enough depth to commission and troubleshoot—not just press Start.
Every circuit ties the symbolic control idea to recognizable hardware, main-current behaviour and the measurements used to prove what is actually wrong.
True contact state
Coils, auxiliary contacts, main poles, latches and interlocks update as the circuit operates.
Probe-based multimeter
Choose exact nodes for voltage and continuity readings, including an explicit live-circuit safety block.
Seven inserted faults
Control fuse, stop chain, coil, welded pole, overload, missing phase and failed interlock.
Motor dynamics
Direction, rpm, inrush, star current reduction, coast-down and load-side power respond over time.
Functional proving
Stop, overload, interlock, rotation and loaded-current checks complete only after demonstrated.
Shipped features · verified 15 July 2026
Motor-control capabilities available now.
These are live product capabilities, not roadmap promises. Five guided circuit workbenches, the full meter model, inserted faults and evidence records are included in Pro.
Circuit library
DOL, forward/reverse, run/jog, Hand/Off/Auto pump control and open-transition star–delta
Real hardware
Recognizable isolator, contactor, overload relay, operator controls and induction motor
Electrical model
Three-phase power path and low-voltage control path with live conductor state
Contact logic
Coils, auxiliary contacts, main poles, latches and electrical/mechanical interlocks
Measurements
Named red/black probe nodes for control voltage, line voltage and isolated continuity
Motor behaviour
Direction, rpm, inrush, star current reduction, transition and coast-down
Diagnostics
Seven inserted faults across supply, stop chain, coil, poles, overload, phases and interlocks
Guidance
Step-by-step actions, reasons, expected evidence and progressive hints for every circuit
Evidence
Functional stop, overload, interlock, direction, transition and loaded-current proving checks
Visual field guide
Eight diagrams that make the control relationship visible.
The illustrations identify the physical devices, the symbolic circuit and the evidence a meter should find. The live workbench then changes the same paths and components as the circuit operates or fails.
Hardware recognition
Start with the components a technician actually sees
The isolator provides visible disconnection, the contactor switches the motor, the overload protects against sustained excess current and the motor converts the three-phase supply into mechanical motion.
DOL control
See exactly how the seal-in path works
START initially energises KM1. The contactor auxiliary contact then closes around START so the coil remains energised after release. STOP or overload opening breaks the same series path.
Reversing
Swap two phases—and block the opposite contactor
Reversal changes phase sequence. Electrical cross-interlocks and a mechanical interlock must prevent forward and reverse contactors from closing together and creating a phase-to-phase fault.
Operator control
Run and jog differ in the holding logic
RUN uses the normal auxiliary seal-in path. JOG deliberately prevents latching, so the motor operates only while the jog command is held and stops when it is released.
Reduced-current starting
Watch the star–open–delta sequence
The main and star contactors start the motor with reduced winding voltage. Star then opens, a transition interval passes, and delta closes for normal running without overlapping the two configurations.
Electrical evidence
Place probes on named nodes
Voltage across A1–A2 proves whether the coil is being commanded. Measuring along the control chain locates the first point where voltage is lost instead of encouraging parts replacement by guesswork.
Motor behaviour
Compare starting methods by current over time
DOL applies full line voltage immediately and produces the largest inrush. Star–delta reduces starting current but introduces sequencing, interlocking and transition requirements.
Troubleshooting
Measure first, then narrow the fault
A structured path separates a missing control supply, an open stop chain, a commanded but failed coil and a closed contactor with missing main power. Dangerous welded-contact and interlock faults remain explicit.
Circuit library
Five starter circuits, each with a different job.
The simulator does not present DOL, reversing, jog, Hand/Off/Auto and star–delta as interchangeable diagrams. It shows what changes in the hardware, control logic, power path and motor response.
| Circuit | Contactors | Defining control feature | Typical task |
|---|---|---|---|
| DOL three-wire | 1 | STOP, overload, START and seal-in auxiliary | Simple fixed-direction pumps, fans and conveyors |
| Forward / reverse | 2 | Cross-interlock, mechanical interlock and phase swap | Hoists, doors, traverses and reversible conveyors |
| Run / jog | 1 | Selectable maintained or momentary control path | Setup, positioning and maintenance movement |
| Hand / Off / Auto | 1 | Maintained local command, OFF override and automatic process demand | Pumps, fans and packaged process equipment |
| Star–delta | 3 | Main, star and delta sequence with open transition | Reduced-current starting of suitable six-lead motors |
Control circuit
The control circuit decides whether a coil is permitted to energise. Its series safety chain normally includes a control fuse, normally-closed STOP, normally-closed overload auxiliary, permissives or interlocks, then the command and coil return. Auxiliary contacts create holding or blocking logic.
Power circuit
The power circuit carries motor current through the isolator or breaker, contactor main poles and overload elements to the motor. The contactor coil can be correctly energised while the power circuit still has a missing phase, open pole or tripped overload.
Fault diagnosis
Use voltage to divide the circuit into smaller questions.
When a motor does not start, begin with the symptom and the approved schematic. Prove the expected control supply, follow voltage through the series chain, determine whether the coil is commanded, and only then move to the three-phase power path. The virtual meter uses named nodes so every reading has an electrical meaning.
Open control fuse
Likely evidence
No control voltage anywhere downstream
Proving action
Measure supply first, then both sides of the fuse.
Open STOP or overload chain
Likely evidence
Voltage enters the chain but does not reach START
Proving action
Find the first series contact with voltage on one side only.
Open contactor coil
Likely evidence
Correct voltage across A1–A2 but no contactor movement
Proving action
Isolate, then verify coil continuity and rating.
Welded main pole
Likely evidence
One phase remains connected after the coil drops out
Proving action
Isolate and compare line-side and load-side pole state.
Missing phase
Likely evidence
Contactor closes but motor current and torque are abnormal
Proving action
Measure all three phase-to-phase paths and inspect the power chain.
Failed reversing interlock
Likely evidence
Forward and reverse can overlap
Proving action
Treat as dangerous; isolate and prove both electrical and mechanical interlocks.
Why continuity mode is blocked while live
Resistance and continuity functions apply a meter’s internal test source; they are not intended to be connected to an energised control circuit. The simulator forces isolation before continuity testing. For live diagnosis it provides voltage mode, named probe points and an explicit live-state warning—training the meter setup as part of the fault-finding method.
Functional proving
Commission the starter after the drawing looks correct.
A tidy schematic is not proof of operation. The commissioning sheet only completes when the learner demonstrates the intended stop, protection, direction and loaded-current behaviour in the simulated circuit.
- 01
Inspect and isolate
Identify Q1, control protection, contactors, overload, operator devices and motor. Confirm the circuit is isolated before continuity work.
- 02
Prove the control chain
Check STOP and overload contacts are closed when healthy, then verify the coil path and auxiliary contact arrangement.
- 03
Energise deliberately
Close the isolator and use the intended momentary control. Observe coil, auxiliary and main-pole state rather than listening only for a click.
- 04
Test every stop path
Prove STOP removes the command and the overload auxiliary drops the contactor. Confirm a broken safety-chain conductor fails to stop.
- 05
Prove direction and interlocks
For reversing, confirm phase sequence and prove the opposite command is blocked electrically and mechanically while running.
- 06
Observe starting behaviour
Compare DOL inrush or the star–open–delta sequence. Confirm no star/delta contactor overlap occurs.
- 07
Measure loaded current
Check the simulated phase condition, current and stable running speed after acceleration. Investigate imbalance or overload evidence.
- 08
Record and diagnose
Insert a fault, locate it with defensible measurements, remove the cause and repeat the affected functional check.
Safety and scope
A realistic mental model, not permission to work live.
The browser lab can make relationships visible without exposing a learner to electrical energy. It can show why a normally-closed stop is fail-safe, why an overload auxiliary sits in the coil path, why reversing needs two forms of interlock and why the meter mode matters.
It cannot assess a person’s practical competence, prove absence of voltage on real equipment, select protection, verify fault level, determine conductor size or replace supervision and local procedures. Those boundaries are displayed because credible training should clarify what has and has not been proven.
Why not full 3D?
A circuit is a relationship map. Keep it readable.
A 3D cabinet is useful for physical panel layout, reach, routing and assembly. It is weaker for understanding which auxiliary contact controls which coil, comparing two live branches or placing probes on named electrical nodes.
This simulator therefore uses realistic 2D hardware inside a schematic workspace, with live highlighting and motor animation. The learner can see the real component and the electrical relationship at the same time—even on a phone.
Continue the motor-control path
Move between wiring, ladder logic and electronic speed control.
The wiring tutor teaches terminal placement, the PLC motor page teaches ladder logic, and the VFD simulator adds parameterised electronic speed control. Cross-linking the tasks helps learners understand where each technology begins and ends.
Questions
Frequently asked.
The simulator includes direct-on-line three-wire control, forward/reverse with electrical and mechanical interlock, run/jog control, Hand/Off/Auto pump control, and open-transition star-delta starting. Each circuit includes the power circuit, 24 V control path, contactor states, overload protection, operator controls, live motor behaviour and guided commissioning checks.