Chart boundary

Does not size a generator, guarantee motor start, account for controls, or replace manufacturer generator sizing software.

voltage dip curve

Starting kVA and voltage dip bands

The curve concept shows why running kW is not enough when the largest motor must start on generator power.

Scopegenerators and backup powerX-axisstarting kVA ratioY-axisvoltage dip percentReviewAnnualNextGenerator load and motor-start sizing calculator
Starting kVA and voltage dip bandsstarting kVA ratiovoltage dip percentStarting kVA ratiolargest motor / generat...Dip bandlow / review / highStart methodATL / soft start / VFDToleranceload-specific
The curve concept shows why running kW is not enough when the largest motor must start on generator power.
Starting kVA and voltage dip bandssensitive load toleranceacceptable dipreview bandhigh dipstarting kVA ratiovoltage dip percent
Starting kVA ratiolargest motor / generator kVA

Running load alone misses transient stress.

Dip bandlow / review / high

Sensitive loads may need tighter recovery.

Start methodATL / soft start / VFD

Method changes inrush shape and torque.

Toleranceload-specific

Controls and electronics can drop out before motors fail.

Decision reference

Show transient motor-starting risk before users run generator sizing or motor locked-rotor calculations.

Reference basis: Kohler, Cummins, and Multiquip generator motor-starting sizing guides.
Curve bandWhat it showsRisk cueHandoff
Running load onlySteady kW or kVA after startMisses transient dipGenerator sizing calculator
Largest motor startStarting kVA drives transient demandExcessive dip or failed startMotor LRA calculator
Reduced-voltage startingLower inrush bandTorque and control details matterMotor starting method chart
Sensitive load busDip tolerance is tighterControl dropoutVoltage sag chart

Use notes

  • Use this chart as a planning and conversation aid only.
  • Confirm current utility requirements, product markings, manufacturer instructions, and local authority requirements before field work.
  • Use the linked calculator or table when the task needs project-specific arithmetic.

Reference sources

Open the underlying public references before treating the chart as project guidance.