Concealed diagnosis
The assessment view removes the visible fault picker and fault-revealing schematic marks.
Browser-based electrical troubleshooting simulator
Find the hidden fault with circuit evidence.
Operate a real motor-control model, place virtual multimeter probes on named nodes, avoid unsafe test modes and submit the diagnosis. The fault changes the circuit—the answer is not written into the story.
Quick answer: the simulator covers control-supply, stop-chain, coil, contact, overload, phase and interlock faults across DOL, reversing and star-delta circuits. Pro adds concealed cases, scoring and saved records.
Experiential, not slide based
The reading changes because the circuit changed.
Each case starts the same tested motor-control engine with one server-selected fault. Inputs, coils, auxiliary contacts, poles, voltage nodes, current, rpm and protection states remain connected, so one fault creates consistent symptoms across the workbench.
Named probe nodes
Measure control points from 24 V through A1–A2 and three-phase points from L to T.
Live motor state
Contactor commands, phase condition, current, rpm, direction and dangerous overlap update over time.
Saved evidence
Correct attempts save diagnosis count, observations, safety mistakes, time and score.
Visual field guide
Eight diagrams explain the simulator, scoring and evidence.
Each figure answers a separate search question: the troubleshooting process, circuit zones, half-split method, meter modes, fault evidence, scoring, attempt state and saved record.
Method
One repeatable loop for every hidden fault
The workbench rewards a circuit hypothesis and a discriminating measurement—not random component swapping.
Circuit map
Separate the control path from the power path
A healthy coil command does not prove the three-phase path. Each zone has named evidence and a different fault family.
Meter strategy
Use voltage to bracket the open circuit
Measure at a point that divides the remaining suspects. The next test follows from the result.
Meter safety
Choose the energy state before the meter mode
The simulator permits voltage evidence while energised and blocks resistance or continuity on the live model.
Fault library
Seven fault families with distinct evidence
Fuse, stop, coil, pole, overload, phase and interlock failures change the actual circuit model instead of revealing a scripted answer.
Scoring
A transparent 70–100 assessment score
The server owns the final answer and score. Wrong diagnoses remain part of the attempt instead of resetting the exercise.
State machine
A pass exists only after a correct diagnosis
An incorrect submission returns the learner to evidence gathering. A completed attempt is idempotent and cannot be scored twice.
Training evidence
Keep the record that makes practice visible
Individuals see recent attempts; team administrators receive member-level rollups and an exportable evidence trail.
Current case library
Faults that force different measurements.
The library begins with starter circuits because they connect control logic, real components, three-phase power and a measurable load. It does not currently claim general residential wiring, PCB repair, arc-flash calculation or safety certification.
Blown control fuse
No contactor response; line power may still be present.
Best first evidence: Compare 24 V before and after F1.
Open STOP chain
START is ignored despite a healthy supply.
Best first evidence: Trace the first lost voltage through the fail-safe series path.
Open contactor coil
Command voltage reaches A1–A2 but the contactor does not pull in.
Best first evidence: Use live voltage evidence, then isolated continuity.
Welded main contact
Load-side voltage remains after the coil command drops.
Best first evidence: Treat the mismatched coil and pole state as dangerous.
Overload trip
The starter stops and the 95–96 path remains open.
Best first evidence: Identify protection state before attempting a reset.
Missing phase
The contactor closes but the motor will not accelerate normally.
Best first evidence: Compare every line and load phase pair.
Failed interlock
Opposing contactors can overlap during reversal or transition.
Best first evidence: Observe the dangerous state, isolate and diagnose the interlock.
Assessment records
Turn practice into evidence an instructor can review.
A completed simulation saves more than a completion tick. It records whether the learner diagnosed efficiently, gathered meter evidence and avoided an unsafe meter setup. Team rollups expose passes, average and best score per member.
See team trainingCase
The hidden work order and motor-control family
Diagnosis
Correct fault and number of submissions
Evidence
Measurement observations and unsafe setups
Outcome
Elapsed time, 70–100 score and timestamp
Simulation boundary
This browser lab develops circuit reasoning and test-selection habits. It does not prove practical competence, authorize electrical work, select PPE, perform a real absence-of-voltage test or replace employer and jurisdictional procedures.
Same login · separate assessment tier
Start with a hidden motor-control fault.
The assessment is built into the existing PLC Simulator Pro app, while the employer path keeps its own reporting, messaging and team workflow.
Questions
Frequently asked.
It includes hidden faults in DOL, reversing and star-delta motor-control circuits, recognizable starter hardware, live control and three-phase paths, named multimeter test points, voltage and isolated-continuity modes, motor behaviour, scored diagnoses and saved attempt evidence.