The practice described herein provides instruction on the testing of distribution transformers as voice-frequency noise generators, to measure the degree to which they may contribute t o electrical noise in communication circuits that are in parallel with the power-supply circuits serving the transformers. Transformers have a characteristic common to other iron-core devices of causing harmonic currents at voice frequencies to flow in supply circuits t o the transformers. The magnitudes of these currents, and of interference that may result, vary according to design of the transformer as well as excitation voltage. The tests described in this practice provide a standard method for use by the transformer manufacturer, user, and others in industry for the purpose of better evaluating the design choices available and moving toward industry objectives as to levels of harmonic exciting current expressed as I*T (current X telephone influence factor [TIF])
- Status
- Superseded Standard
- Superseded by
- 469-1988
- Board Approval
- 1976-09-09
- History
-
- Published:
- 1977-07-29
Working Group Details
Other Activities From This Working Group
Current projects that have been authorized by the IEEE SA Standards Board to develop a standard.
No Active Projects
Standards approved by the IEEE SA Standards Board that are within the 10-year lifecycle.
No Active Standards
These standards have been replaced with a revised version of the standard, or by a compilation of the original active standard and all its existing amendments, corrigenda, and errata.
No Superseded Standards
These standards have been removed from active status through a ballot where the standard is made inactive as a consensus decision of a balloting group.
No Inactive-Withdrawn Standards
These standards are removed from active status through an administrative process for standards that have not undergone a revision process within 10 years.
No Inactive-Reserved Standards