TB 9-4931-401-24
provide a four-to-one ratio between the standard and TI. Where the four-to-one ratio
cannot be met, the actual accuracy of the equipment selected is shown in parenthesis.
5. Accessories Required. The accessories required for this calibration are common
usage accessories, issued as indicated in paragraph 4 above, and are not listed in this
calibration procedure. The following peculiar accessory is also required for this calibration:
Decade Resistor, Winslow, Model 336 (7907234) or Clarostat, Model 240C (240C).
Table 2. Minimum Specifications of Equipment Required
Manufacturer and model
Common name
Minimum use specifications
(part number)
Ridge, Model 9020A
AUTOTRANSFORMER
Range: 05 to 125 V ac
Accuracy: 1%
(9020A)
Fluke, Model 80E10
HIGH VOLTAGE DIVIDER
Range: 1000 to 1
(80E10)
Accuracy: 1
Agilent, Model 3458A
(3458A)
Range: 30 mV to 902.25 V dc
Accuracy: 0.0625%
1
Fluke, Model 8922A/AA
TRUE RMS VOLTMETER
Range: 0 to 1 mV ac
Accuracy: 3%
(8922A/AA)
accuracy of multimeter and high voltage divider must be 0.0625%
1Combined
CALIBRATION PROCESS
6. Preliminary Instructions
a. The instruction outlined in paragraphs 6 and 7 are preparatory to the calibration
process. Personnel should become familiar with the entire bulletin before beginning the
calibration.
b. Items of equipment used in this procedure are referenced within the text by common
name as listed in table 2.
c. Unless otherwise specified, verify the result of each test and, whenever the test
requirement is not met, take corrective action before continuing with the calibration.
Adjustments required to calibrate the TI are included in this procedure. Additional
maintenance information is contained in the manufacturer's manual for this TI.
d. Unless otherwise specified, all controls and control settings refer to the TI.
7. Equipment Setup
HIGH VOLTAGE is used or exposed during the performance of
this calibration.
DEATH ON CONTACT may result if
personnel fail to observe safety precautions. REDUCE
OUTPUT(S) to minimum after each step within the
performance check where applicable.
a. Connect TI to autotransformer.