NIST measurement services: Calibration service for current transformers. Special pub. (Final)

Technical Report · Sat Jun 01 04:00:00 EDT 1991

OSTI ID:5335826

Ramboz, J D; Petersons, O

A calibration service at the National Institute of Standards and Technology (NIST) for laboratory-quality current transformers is described. The service provides measurements of the current ratio and the phase angle between the secondary and primary currents. In the Report of Calibration or Test, the measured ratio is reported as the product of the marked (nominal) ratio and the ratio correction factor. The measured phase angle is reported directly in milliradians (mrad) and is positive if the secondary current leads the primary. The range of primary-to-secondary current ratios that can be measured with the equipment at NIST extends from 0.25 A:5 A to 12000 A:5 A. The maximum current at the present time is about 20000 A. Estimates of calibration uncertainties, including their sources, are given and quality control procedures are described. For routine calibrations, uncertainties of + or - 0.01% for the ratio and + or - 0.1 mrad for the phase angle are quoted. However, lower uncertainties--to + or - 0.0005% or 5 parts per million (ppm) for ratio and + or - 0.005 mrad or 5 microrads for phase angle--are possible under the provisions of Special Tests.

• Research Organization: National Inst. of Standards and Technology (EEEL), Gaithersburg, MD (United States)
• OSTI ID: 5335826
• Report Number(s): PB-91-216770/XAB; NIST/SP--250/36
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420500* -- Engineering-- Materials Testing
ACCURACY
CALIBRATION
CONTROL
CURRENTS
ELECTRIC CURRENTS
ELECTRICAL EQUIPMENT
EQUIPMENT
LABORATORY EQUIPMENT
NATIONAL ORGANIZATIONS
QUALITY CONTROL
STANDARDS
TRANSFORMERS
US ORGANIZATIONS