TB 9-6625-1878-40
IDENTIFICATION AND DESCRIPTION
1. Test Instrument Identification.
This bulletin provides instructions for the
calibration of Ratio Transformer Gertsch, Models RT2, RT5, RT7R, TF515/U (RT 60),
TF384/U (RT 7), and North Atlantic Model RB503/10S1702 and Decade Transformer ESI,
Model DT72A. The manufacturers' manuals were used as the prime data sources in
compiling these instructions. The equipment being calibrated will be referred to as the TI
(test instrument) throughout this bulletin.
a. Model Variations. Variations among models are described in the text.
b. Time and Technique. The time required for this calibration is approximately 2
hours, using the dc and low frequency.
2. Forms, Records, and Reports
a. Forms, records, and reports required for calibration personnel at all levels are
prescribed by TB 750-25.
b. Adjustments to be reported are designated (R) at the end of the sentence in which
they appear When adjustments are in tables, the (R) follows the designated adjustment.
Report only those adjustments made and designated with (R).
3. Calibration Description. TI parameters and performance specifications which
pertain to this calibration are listed in table 1.
Table 1. Calibration Description
Test instrument parameters
Performance specifications
Range: 0.0 to 1.0
Ratio:
Ratio accuracy:
Gertsch, Models RT2, RT5,
50 Hz to3 kHz1 (0.001% + 0.0001% / ratio)
RT7R, RT11R, RT12R, TF515/U
3 kHz to 10 kHz1 (0.01% + 0.001% / ratio)
(RT60), TF384/U (RT7), and
North Atlantic, Model
RB503/10S1702
Range: 0.0100000 to 1.0000000
ESI, Model DT72A
Terminal linearity1, 2: 50 Hz and 1 kHz
Settings: 0.1 to 1.1111110 0.5 ppm
Settings: 0.0111111 to 0.1 (0.5 (10 x setting)1, 2 + 0.01) ppm
'Procedure limitations: calibrated at 50 Hz to 1 kHz only.
Terminal linearity derated to 0.001% by Engineering Directorate, USATA.
2
EQUIPMENT REQUIREMENTS
calibration procedure. This equipment is issued with Secondary Reference Calibration
Standards Set SSN 4931-621-7878 and is to be used in performing this procedure.
Alternate items may be used by the calibrating activity. The items selected must be
verified to perform satisfactorily prior to use and must bear evidence of current calibration.
