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 ratiostarting kVA ratiovoltage dip percentvoltage dip percentStarting kVA ratioStarting kVA ratiolargest motor / generator kVAlargest motor /genera...Dip bandDip bandlow / review / highlow /review /highStart methodStart methodATL / soft start / VFDATL /soft start /VFDToleranceToleranceload-specificload-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 tolerancesensitive load tole...acceptable dipacceptable dipreview bandreview bandhigh diphigh dipstarting kVA ratiostarting kVA ratiovoltage dip percentvoltage 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 table

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

Scroll sideways to keep row labels aligned with hidden columns.

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
Notes
  • Treat 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.

Source links

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