Abstract： IEC 60076-21:2011 pdf free download.Power transformers - Part 21: Standard requirements, terminology, and test code for step-voltage regulators. NOTE I —For self-ventilated equipment, the ambient temperature is the average temperature of...

IEC 60076-21:2011 pdf free download.Power transformers - Part 21: Standard requirements, terminology, and test code for

step-voltage regulators.

NOTE I —For self-ventilated equipment, the ambient temperature is the average temperature of the air in the immediaie neighbothood of the equipment.5

NOTE 2— For air cooled equipment with forced ventilation, the ambient temperature is taken as that of the in-going

angular displacement of a three-phase sollage regulator or bank of three single-phase sollage regulators: (A) The time angle.

expressed in degrees. between the line-to-neutral voltage of the reference source voltage terminal and the line-to-neutral voltage of the corresponding load voltage tenninal. (B) The connection and arrangement of terminal markings for a three-phase voltage

regulator or bank of three single-phase voltage regulators in a wye connection has an angular displacemern of zero degrees. (C) The connection and arrangement of terminal markings for a three-phase voltage regulator or bank of three single-phase voltage

regulators in a delta connection has an angular displacement of zero degrees when the voltage regulators are on the neutral tap

position. When the voltage regulators are on a tap position other than neutral, the angular displacement will be other than zero

degrees. The angular displacement with the voltage regulators connected in delta will be less than +5° for a ±10% range of

regulation.

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