Generator Evaluation

Evaluating Portable Generators

For Reliability, Service Life and Value

Reading Electric, a leading supplier of electro-mechanical equipment, services, and problem solver for Industrial and Commercial customers for over 50 years provides technical information to the Region’s Residential, Commercial and Industrial Community. This Bulletin provides information on the evaluation of Portable Generators for maximum Service Life and Value.

Today there many Portable Generators to choose from in the 3Kw to 15Kw power with a broad range of options and prices. Purchasing a Portable Generator under conditions of ‘haste’ many times can lead to selecting a generator that will leave you without power when you most need it. Given below is list of items that need to be considered when selecting a Portable Generator. This Check List is based on our experience, and actual experiences of users who rely on portable generators for emergency power back-up.

Electrical Power Generating Sine-Wave Performance

Most voltage sensitive loads such as UPS systems, computers, microprocessors, and all other micro-chip ladened equipment, can withstand up to typically 10% harmonic sine-wave distortion without the possibility of in-operative or damaged equipment. A typical brush-less portable generator with capacitor voltage regulation will produce from 30% to 40% harmful harmonic distortions in the generated sine-wave.

Normal Utility Power Sine-Wave with Average 3% Harmonic Distortion & Less Than 25 TIF*


Engine & Fuel Systems

  • OHV Engine design with cast-iron cylinder sleeves
  • Oil Pressure sensor with automatic engine shut-down
  • Separate ‘spin-on’ oil filter and full pressure oil system on 9-15kw units
  • Minimum 4 gallon fuel tank on 3 to 7.5Kw units, 8 gallon minimum on
    9 Kw units
  • Ethanol E85 compatible fuel tank and fuel line components
  • Run Time Hour Meter
  • Two element air cleaner filter

Generator System

  • Windings manufactured with Class H, 180°C to 200°C insulation
  • Life Time Warranty on Rectifier Circuit Diodes and Voltage Regulating
  • Ground Fault Circuit Interrupters (GFCI) – OSHA/NEC Compliance
  • Magnetic Circuit Breakers for winding and electrical circuit overload
  • Volt Meter
  • Weather covers on electrical outlets

Portability & Packaging

  • Pneumatic tires (at least 10”) on units of 9-15Kw
Important Note: It is always good practice to install external surge protection and or UPS on sensitive electronics being powered by the utility or standby generation.