NEMA TP 2-2005

Foreword
Section 1 - GENERAL
  1.1 Scope
  1.2 Referenced Standards
  1.3 Definitions
Section 2 - ACCURACY REQUIREMENTS
  2.1 General Considerations
Section 3 - RESISTANCE MEASUREMENTS
  3.1 General Considerations
  3.2 Temperature Determination of windings and
      Pre-Conditions
      3.2.1 Liquid-Immersed Distribution Transformers
  3.3 Resistance Measurement Methods
      3.3.1 Resistance Bridge Methods
      3.3.2 Voltmeter-Ammeter Method
      3.3.3 Resistance Meters
  3.4 Precautions in Measuring Winding Resistance
      3.4.1 Required actions
      3.4.2 Guideline for the Time Constant
  3.5 Conversation of Resistance Measurements
Section 4 - LOSS MEASUREMENT
  4.1 General Considerations
  4.2 Measurement of Power Losses
      4.2.1 No-Load Loss
      4.2.2 Load Loss
  4.3 Test Sets
      4.3.1 Single-Phase Test Sets
      4.3.2 Three-Phase Test Sets
      4.3.3 Test of Three-Phase Transformer with
            Single-Phase Voltage
      4.3.4 Test Set Neutrals
  4.4 No-Load Losses: Measurement and Calculations
      4.4.1 General Considerations
      4.4.2 No-Load Loss Test
      4.4.3 Corrections
  4.5 Load Losses: Measurement and Calculations
      4.5.1 General Considerations
      4.5.2 Tests for Measuring Load Losses
      4.5.3 Corrections
Section 5 - DETERMINING THE EFFICIENCY VALUE OF
            THE TRANSFORMER
  5.1 Output Loading Level Adjustment
  5.2 Total Loss Power Calculation
  5.3 Energy Efficiency Calculation
  5.4 Significant Figures in Power Loss and Efficiency Data
Section 6 - TEST EQUIPMENT CALIBRATION AND CERTIFICATION
  6.1 Test Equipment
  6.2 Calibration and Certification
Section 7 - MANUFACTURER'S DETERMINATION OF EFFICIENCY
            for distribution transformers
  7.1 Methods Used to Determine Efficiency
      7.1.1 General Requirements
      7.1.2 Alternative Efficiency Determination Method
      7.1.3 Substantiation of an Alternative Efficiency
            Determination Method
      7.1.4 Subsequent Verification of an AEDM
  7.2 Additional Testing Requirements
      7.2.1 Selection of Basic Modes for Testing if an
            AEDM is to be Applied
      7.2.2 Selection of Units for Testing Within a Basic
            Model

Describes single-phase dry-type and liquid-immersed distribution transformers at 60 Hz for the North American system (transformers for transferring electrical energy from a primary distribution circuit to a secondary distribution circuit or within a secondary distribution.