Attachment_1_PD_19E-513A-DC_Rev_6_dated_12_December_2018.pdf

DIRECTORATE OF METRO LOGY

PURCHASE DESCRIPTION

FOR

Kelvin-Varley Voltage Divider

19E-513A-DC

December 12, 2018

Revision # 6

1.0 SCOPE: This purchase description identifies the performance requirements for a Kelvin-Varley style Voltage Divider, hereafter referred to as the KVVD.

1.1 . General Description of Hardware: High-resolution Primary Calibration-grade Ratio

Standard with absolute linearity of 0 .1 ppm, temperature coefficient of linearity of 0.05 ppm/°C, and self-calibration capability

1.2. Types of Workload Supported: AFPSL Field workload includes Digital Multimeters, Precision DC Sources/Calibrators, Thermocouple Simulators/Calibrators, other Precision DC Voltage Ratio-Dividers I Dial-A-Viders / Dekaviders, DC Voltage Standards/Calibrators, Differential Voltmeters, Null Detectors, Nanovoltmeters/MicroOhmmeters, Multifunction/Meter Calibrators, DC Reference Standards, Wideband Floating Differential / Signal Conditioning Amplifiers, Thermal True RMS Multimeters, and Digital Strain Indicators

1.3. Item is replacing the Fluke Model 720A, which is currently being used at the AFPSL and PMELs

2.0 COMPONENT: Listed in this purchase description are the Air Force minimum functional requirements which are to be satisfied

3.0 COMPATIBILITY: This item must be compatible with equipment currently in use by the Air Force in the Direct Current/Low Frequency measurement area. Items such as calibrators, high accuracy digital multimeters and other test equipment shall be supportable with this KVVD without limitation due to lack of capability of the KVVD.

4.0 PERFORMANCE REQUIREMENTS:

4.1. DC Voltage Ratio Range: 0: 1.1 ( division ratio output to input) 0.0: 1.0 to 1.0: 1.0 for the

1.0 input terrnination(s) and 0.0 : 1.1 to 1.1 : 1.1 for the 1.1 input terrnination(s)

4.2. Resolution: 0 .1 ppm of input with seven (7) decades

4.3. Absolute Linearity: defined as the linearity between maximum and minimum output voltages (at calibration temperature and without the use of a correction chart) ±0 .1 ppm of input at dial settings of 1.1 to O .1 ±0.1(10S)113 ppm of input at dial settings of 0.1 to 0, where S=dial setting

4.4. Absolute Linearity Stability:

4.4.1 . Short-Term Linearity Stability: Under typical standards laboratory conditions

(temperature maintained within ±1 °C) and with an applied voltage of up to 100 volts stability oflinearity is ±0.01 ppm/24 hours and ±0.1 ppm/30 days

4.4.2. Long-Term Linearity Stability: (without self-calibration) ±1 .0 ppm of input per year at dial settings of 1.1 to 0.1

± 1.0(1 OS)213 ppm of input per year at dial settings of 0.1 to 0, where S=dial setting (performing self-calibration at any time will reset the linearity to ±0.1 ppm of input)

4.5. Temperature Coefficient of Linearity: ±0.05 ppm of input/cc maximum at dial settings of 1.1 to 0.1

4.6 . Power Coefficient of Linearity: ±0.2 ppm of input per watt maximum at dial settings of

1.1 to 0.1 and ±0.2(10S)2 ppm of input per watt at dial settings of 0.1 to 0

4.7. Maximum End Errors:

Zero error, at output low; 0.004 ppm of input Zero error, at input low; 0.05 ppm of input Full-scale error; 0.05 ppm of input

4.8 . Thermal Voltages: ±0.5 micro Volt maximum

4.9. Maximum Input Power: 10 watts at the 1.0 input terminals, and 11 watts at the 1.1 input terminals

4.10. Maximum Input Voltage: 1000 volts at the 1.0 input terminals, and 1100 volts at the 1.1 input terminals

4.11. Breakdown Voltage: 2000 volts to case at 10,000 feet and 2500 volts to case at sea level

4.12. Input Resistance: 100 kohms ±50 ppm at the 1.0 input terminals at 25 cc , and 110 kohms ±50 ppm at the 1.1 input terminals at 25 cc 4 .13 . Maximum Output Resistance: 66 kohm, determined by shorting across the input terminals and measuring the resistance across the output terminals

4.14. Terminals : Low-thermal emf tellurium copper 3-way binding posts

5.0 FUNCTIONAL REQUIREMENTS:

5.1. Automate or Manual Control: Manually Controlled

5.2. Ancillary Equipment: The unit shall be provided with all necessary accessories to enable rack mounting in a standard 19 inch rack

5.3. Self-Calibration: as additional minimum feature, the KVVD shall have a self-calibration procedure to adjust step resistance and overall resistance of the first two decades to compensate for resistance changes caused by temperature changes and aging

5.4. International Standards & Publications: Calibration requirements IA W ISO/IEC 17025, A2LA accreditation standards, and NIST/NMI traceable Reports of Calibration

6.0 MECHANICAL & PHYSICAL REQUIREMENTS:

6.1. Dimensions and Weight: No larger than 5.5 inches (14 cm) height, 13 inches (33 cm) depth, and capable of fitting into a standard 19 inch (48 .3 cm) rack. 20 lbs. (9.1 kg) maximum

6.2. Operating Environment/Storage:

6.2 .1. Operating Temperature Range: The unit shall perform to full specifications at

22.8 cc ±3 .3 cc

6.2.2. Operating Humidity Range: The unit shall perform to full specifications from 20 to 50 % RH

6.2.3. Storage Temperature: -20 cc to +60 cc

6.2.4. Storage Humidity: 15 to 80 % RH

6.3. Commercial Parts: Commercial parts and materials that are to be supplied shall have properties consistent with a precision laboratory instrument

6.4. Design and Construction: The equipment will be designed and constructed of materials that meet the requirements of this specification and in accordance with the best commercial practices for industry approved equipment. It will be the contractor's responsibility to assure the government that such design objectives as reliability, accuracy of operation, maintainability and ease of operation have been given due consideration in the manufacture of this equipment. All parts such as shafts, bearings, resistors, switches, controls, potentiometers, etc. shall have proper clearance and adjustments. They shall so work together that the equipment will supply the rated requirements without unnecessary strains, vibrations and overheating. They shall be able to withstand the conditions met in shipping, storage, installation and services. All material and parts of this equipment shall be capable of withstanding environmental testing requirements of this specification.

6.5. Selected Components: Matched and selected components shall be kept to an absolute minimum. Use of specially built non-standard components other than switches and similar individual assemblies shall be avoided whenever possible.

6.6. Metals: Metals shall be of corrosion resistant type or suitably treated to resist corrosion due to atmospheric conditions likely to be met in storage, services or transportation.

Dissimilar metals in intimate contact should be kept to a minimum.

6.7. Circuit Boards: Frequent shipping will require that all circuit boards be sufficiently secured by their connectors and be held in place by securing screws or other such hold down devices

7.0 WORKMANSHIP: The workmanship shall be first class, of neat general appearance and shall comply with standard commercial practices. The standards of workmanship shall be such that the KVVD shall comply with the requirements in Sections 2.0 through 8.0 of this description. All components, subassemblies and final assembly shall comply with the examination and test in Section 9.0.

8.0 SAFETY: Equipment shall be designed such that it will not be of any hazard to itself or to any person operating it using reasonable precautionary procedures

9.0 QUALITY ASSURANCE: This item shall be inspected and tested at destination, as specified elsewhere in this contract. This item will be checked with test equipment with parameters equal to or better than those required to assure specified performance requirements are met. Test equipment used is traceable to the National Institute of Standards and Technology when/where required. Tests will be performed to assure the item meets the requirements of this purchase description. Such testing at destination does not relieve the contractor of performing all inspections and quality checks at the point of fabrication, as specified elsewhere in this contract, or as necessary, to ensure performance, as specified herein.

10.0 CALIBRATION: ISO/IEC 17025 Accredited Calibration by a Primary Lab. Calibration documentation shall be provided. Report to include results from tests which utilize an intrinsic Josephson Junction Standard, to ensure that the KVVD meets specifications with proper Test Uncertainty Ratios.

11 .0 WARRANTY: The equipment, including all accessories, shall be covered by a I-year standard warranty as described within the attached Warranty Description

Attachment:

Data Requirements

Attachment to Purchase Description 19E-513A-DC

Kelvin-Varley Voltage Divider

DATA REQUIREMENTS

MANUALS: A complete user and service manual and calibration procedure shall be provided with each unit in contractor format. Manuals shall be on CD/DVD-ROM in Indexed Portable Document Format

(iPDF) . The manuals shall comply with Data Item Description (DID) DI-TMSS-80527C and the Contract

Data Requirements List (DD Form 1423).

CALIBRATION CERTIFICATE: A calibration certificate, traceable to the National Institute of Standards and Technology (NIST) or other national metrology institutes (NM ls) shall be provided with each instrument. This calibration certificate must comply with Data Item Description (DID) DI-QCIC-80798C and the Contract Data Requirements List (DD Form 1423).