Motor starting current workflow

How to prepare full-load current and starting-method assumptions before using the Australian motor starting current calculator.

Starting-current purpose

Starting current is often much higher than running current. A transparent worksheet helps show which full-load current and multiplier were used before a voltage-dip, generator or protection question is reviewed.

The useful output is not a final starter selection. It is a documented starting-current estimate and its assumptions.

Workflow

  1. Confirm the full-load current source: nameplate, schedule, calculated estimate or measured record.
  2. Choose a starting method or multiplier that matches the worksheet assumption.
  3. Calculate starting current.
  4. Record whether the multiplier is generic, project-specified or manufacturer-derived.
  5. Carry the result into voltage-dip, generator or protection review with the assumption source attached.

Starting record

Starting-current worksheet fields
FieldRecordReview concern
FLC sourceNameplate, calculated, schedule or measuredWeak source weakens the result
Starting methodDirect-on-line, soft starter, VSD bypass or other documented methodCurrent depends on method
MultiplierEntered multiple of FLCMust be labelled as assumption or product data
Starting currentCalculated A valueFeeds dip, generator and protection review
Product sourceStarter or drive data where usedRequired before product-specific conclusions

Boundaries

  • Do not hide the starting multiplier source.
  • Do not infer starting torque, acceleration or protection behaviour from current alone.
  • Do not treat generic multipliers as manufacturer data.
  • Do not move the result into generator sizing without also checking running loads and voltage behaviour.