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Equipment Technology Rental

ETR — Equipment Technology Rental

How to Select the Right Rental Generator Capacity

Generator selection starts with the loads and electrical interfaces, not with a preferred kVA number. This guide helps procurement and site teams assemble a useful brief for technical review.

1. Build a load schedule

  • List every load expected to operate, its running kW or current, voltage, phase and frequency.
  • Separate loads that operate continuously from intermittent loads and identify which loads may run at the same time.
  • Record the largest motors, compressors, pumps, welders, variable-frequency drives and other loads that can affect starting or waveform performance.

2. Check starting demand and load steps

  • Motor and compressor starting demand can be materially higher than normal running demand.
  • State the starting method and nameplate starting information when available. Do not estimate locked-rotor or inrush values when verified data exists.
  • A planned start sequence can reduce the largest simultaneous load step, but the sequence must match actual site operations.

3. Confirm the electrical system

  • Confirm operating voltage, phase and frequency for the loads and the selected generator. A general fleet voltage list does not mean every unit supports every combination.
  • Identify distribution boards, outgoing circuits, protection requirements, earthing arrangements and responsible approved electrical design.
  • Provide cable lengths, route conditions and crossings so cable selection and voltage-drop review can be completed.

4. Use calculations as screening tools only

  • For a balanced three-phase supply, apparent power can be screened as kVA = (√3 × V × I) / 1000. The inputs must use compatible line voltage and current.
  • Converting kW to kVA requires an appropriate power factor: kVA = kW / power factor. Do not assume a power factor when the load data or responsible design provides one.
  • ETR published current values are calculated and rounded for planning. The 75% figure is ETR continuous-load guidance, not a manufacturer-certified rating.

5. Information to send with the quote request

  • Project location, operating dates and daily operating schedule.
  • Load schedule, largest starting load, critical loads and expected future load.
  • Voltage, phase, frequency, cable distances, distribution approach, access and placement constraints.
  • Required accessories and technical-support scope.

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