UL 1004-4
Standard for Electric Generators

Edition Number:3SCC Approved:--
Edition Date:2018-07-02DOD Approved: --
Price Code:AANSI Approved: 2018-06-29


    1 Scope

    1.1 This Standard is intended to be read together with the Standard for Rotating Electrical Machines – General Requirements, UL 1004-1. The requirements in this Standard supplement or amend the requirements in UL 1004-1. The requirements of UL 1004-1 apply unless modified by this Standard.

    1.2 This Standard covers electric generators, also referred to as alternators, which, when coupled with prime movers, such as engines or electric motors, are used to produce electricity. This Standard covers generators, including those for standby use rated 34,000 volts or less.

    1.3 This Standard does not cover stationary or portable generator assemblies, which are respectively covered under the Standard for Stationary Engine Generator Assemblies, UL 2200, and the Standard for Carbon Monoxide (CO) Emission Rate of Portable Generators, UL 2201.

    1.4 This Standard does not cover generators intended for use in hazardous locations as defined in the National Electrical Code ®, NFPA 70.

    The National Electrical Code® and NEC® are registered trademarks of the National Fire Protection Association, Inc., Quincy, MA 02169.

    1.5 In the context of this document, the term generators shall be understood to apply to both AC and DC machines.

    Expand All

    • Cover
    • Transmittal
    • Table of Contents
      • Body
          • 1 Scope
          • 2 Components
          • 3 Glossary
          • 4 General
          • 5 Overspeed Test
          • 6 Short Circuit Test
          • 7 Output Waveform Distortion
          • 8 Surge Tests
          • 9 Temperature Test for Standby Generators
        • MARKINGS
          • 10 General
          • 11 General
    • Appendix A – Surge testing of induction machines