Induction Motor Slip & Speed Calculator

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Electrical & Electronics Engineering — Circuits, Power Systems, Electronics Lab

Tranche

tranche-4

Evidence ID

t4-078

Ledger rows

1

No ledger note is attached.

Review findings

Core formulas are standard under the stated unit assumptions, but the specification is ambiguous because input units and pole-count meaning are not explicitly declared. The formula/output mismatch for slip percentage must be corrected or documented. The honest_label field is empty; it should disclose the Hz/rpm assumptions, positive-even pole-count requirement, percentage conversion, and behavior for zero frequency or overspeed.

Formula and scope findings

• The synchronous-speed formula Ns=120f/P is standard when f is in Hz and P is the total number of poles, producing Ns in rpm.
• The slip formula (Ns−Nr)/Ns is standard and returns a dimensionless fraction, but the declared output is slip %, so the displayed percentage must be 100×(Ns−Nr)/Ns.
• The rotor-frequency formula fr=slip·f is correct only when slip is the fractional value, not the displayed percentage value.

Unit assumptions

• Frequency f must be specified in hertz (Hz).
• Pole count P means total stator pole count and should be a positive even integer.
• Rotor speed Nr must be specified in revolutions per minute (rpm), matching Ns.
• Ns is reported in rpm, slip is internally a fraction and externally a percentage, and fr is reported in Hz.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

A zero pole count produces division by zero in the synchronous-speed formula, so the calculator must reject that input. The specification does not state validation behavior, creating a potential undefined, Infinity, or NaN result.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "frequency_Hz": 50,
    "pole_count": 4,
    "rotor_speed_rpm": 1440
  },
  "expected_outputs": {
    "Ns_rpm": 1500,
    "slip_percent": 4,
    "rotor_frequency_Hz": 2
  },
  "working": "Ns = 120×50÷4 = 6000÷4 = 1500 rpm. Slip fraction = (1500−1440)÷1500 = 60÷1500 = 0.04. Slip percent = 0.04×100 = 4%. Rotor frequency = 0.04×50 = 2 Hz."
}

Related workflows

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche4/tranche4-results.json
• BOUNDARY_HAZARD_CATALOG.json