NEMA TP 2

Description / Abstract: Provides the basis for determining the energy efficiency of single- and three-phase dry-type and liquid-immersed distribution transformers and assists with the proper selection of such equipment.

This standard is intended for use as a basis for determining the energy efficiency performance of the equipment covered and to assist in the proper selection of such equipment.

This standard covers single-phase and three-phase dry-type and liquid-immersed distribution transformers at 60Hz 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 circuit)

This standard addresses the test procedures for determining the efficiency performance of the transformers covered in NEMA Publication TP 1.

Products excepted from this standard include:

a. Autotransformers

b. Drive (Isolation) transformer

c. Grounding transformers

d. Machine tool (Control) transformers

e. Non-ventilated transformers

f. Rectifier transformers

g. Regulating transformers

h. Sealed transformers

i. Special impedance transformers

j. Testing transformers

k. Transformers with tap ranges greater than 15 percent

l. Uninteruptible Power Supply (UPS) transformers

m. Welding transformers

n. Mining transformers

o. K rated transformer, when tested with K1 (see Section 4.2.1)

NOTE—This standard does apply to K rated transformer when tested with K=1.