Fluke A40B Instruction Manual

Precision ac current shunt set
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A40B
Precision AC Current Shunt Set
Instruction Manual
July 2008 Rev. 2, 11/15
© 2008-2015 Fluke Corporation. All rights reserved. Specifications are subject to change without notice.
All product names are trademarks of their respective companies.

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Summary of Contents for Fluke A40B

  • Page 1 A40B Precision AC Current Shunt Set Instruction Manual July 2008 Rev. 2, 11/15 © 2008-2015 Fluke Corporation. All rights reserved. Specifications are subject to change without notice. All product names are trademarks of their respective companies.
  • Page 2 Fluke authorized resellers shall extend this warranty on new and unused products to end-user customers only but have no authority to extend a greater or different warranty on behalf of Fluke. Warranty support is available only if product is purchased through a Fluke authorized sales outlet or Buyer has paid the applicable international price.
  • Page 3: Table Of Contents

    General Maintenance/Cleaning ............11 Operating Information ................11 Feature Descriptions ................. 11 Input/Output Connectors ..............13 Maximum Current ................14 Operating Environment ..............14 Correcting for Current Shunt Error Contributions ......14 Output Voltage Measurement Using a Fluke Calibration 5790B ..15...
  • Page 4 A40B Instruction Manual Output Voltage Measurement – Loading Effect ......... 15 Output Voltage Measurement Using a Fluke Calibration 5790A ..16 Output Voltage Measurement Using a Fluke Calibration 8508A ..17 Operating Instructions ................18 Introduction ..................18 Measuring Current ................18 Direct Read-out When Measuring Current ........
  • Page 5 Estimating the Uncertainty of a 5790B Measurement ....... 19 Sample Calculation of Measured Current ..........20 Single Junction Thermal Voltage Converters ..........23 Fluke Calibration 792A AC/DC Transfer Standard ........23 Fluke Calibration 5790A/B Measurement Standard ........24 Other Error Sources and Solutions ............25 List of Recommended Equipment .............
  • Page 6 A40B Instruction Manual...
  • Page 7 Current Shunt - Simplified Electrical Diagram ........... 21 Circuit Using a Reference Shunt Resistor to Determine Source Current .. 22 Sources of Error in AC Measurements ............25 The Fluke Calibration System ..............26 Calibrating Gain Difference ............... 27 Characterizing Sensitivity ................28 AC/DC Difference Sequence ..............
  • Page 8 A40B Instruction Manual...
  • Page 9: Introduction And Specifications

    Introduction and Specifications About the Manual This is the Instruction Manual for the A40B Precision AC Current Shunt Set (hereafter referred to as the Current Shunt, Current Shunts, or Product). It contains all of the information a Calibration Technician needs to operate and maintain the Current Shunts.
  • Page 10 A40B Instruction Manual XW Warning To prevent possible electrical shock, fire, or personal injury, or death: • Read all safety information before you use the Product. • Use the Current Shunts only as specified in this manual. • To avoid damage to eyes, skin, and the respiratory system, do not significantly exceed the maximum current rating of a shunt.
  • Page 11: Symbols

    Precision AC Current Shunt Set Introduction and Specifications • If batteries are removed from the Shunt, ensure they are re- inserted with the correct polarity. • Use only the battery charger provided to charge the 1 mA active shunt. • Always connect the Battery Charger / Power Adapter to the AC outlet before connecting it to the shunt.
  • Page 12: Product Description

    Instruction Manual Product Description The A40B Precision AC Current Shunt Set consists of 14 Current Shunts, adapters, and a rugged transit/storage case. The Current Shunts are designed for laboratory use in making AC-DC current measurements or absolute AC or DC current measurements.
  • Page 13: Electrical Specifications

    Precision AC Current Shunt Set Electrical Specifications Electrical Specifications Current Shunt Basic Specification These devices are precision calibration reference standards. In order to attain the best performance of the product, the end-user should develop an uncertainty analysis based on their particular use. The uncertainty analysis should include stability of the device over time (usually much better than the specification), humidity and temperature effects for the laboratory, measurement uncertainty of the calibrated value at DC and the uncertainty of the AC-DC difference correction When the best performance of the product is not needed, the following table provides an approximate uncertainty stated...
  • Page 14: Resistance Specifications

    A40B Instruction Manual Resistance Specifications Approximate Maximum Uncertainty of Power Deviation 12 Month Temperature Nominal Calibrated Coefficient Shunt Nominal from Nominal Stability Coefficient Resistance Value at 95 % Multiplier Current [1][2] Resistance (Ohms) Confidence (±μΩ/Ω) (±μΩ/Ω/ºC) [2][3] (±μΩ/Ω) (±μΩ/Ω) (±μΩ/Ω) TCal ±1°C...
  • Page 15: Maximum Ac-Dc Difference At Time Of Manufacture

    Precision AC Current Shunt Set Maximum AC-DC Difference at time of Manufacture [1][2] Maximum AC-DC Difference (±μA/A) Shunt Nominal Current 1 kHz 10 kHz 30 kHz 100 kHz 1 mA 10 mA 20 mA 50 mA 100 mA 200 mA 500 mA 10 A 20 A...
  • Page 16: General Specifications

    A40B Instruction Manual General Specifications Dimensions (maximum) Height Width Overall Length Shunt Value mm (inches) mm (inches) mm (inches) 1 mA to 2 A 70 (2.75) 70 (2.75) 124 (4.9) 5 A to 20 A 130 (5) 130 (5) 210 (8.25) 50 A and 100 A 200 (7.9)
  • Page 17: Preparing For Operation

    As part of the inspection process, check the contents against the list shown in Table 1. Report any shortages to the nearest Fluke Calibration Technical Service Center. See How to Contact Fluke Calibration. Save the container and any packing material for future use in storing or shipping the Current Shunts Table 1.
  • Page 18: How To Contact Fluke Calibration

    China: +86-400-810-3435 • Brazil: +55-11-3759-7600 • Anywhere in the world: +1-425-446-6110 To see product information and download the latest manual supplements, visit Fluke Calibration’s website at www.flukecal.com. To register your product, visit http://flukecal.com/register-product. Shipping Information To prepare the Current Shunt Set for shipping, place them in the appropriate pre- cut foam insert positions in the transit/storage case and secure the lid.
  • Page 19: General Maintenance/Cleaning

    (see MIL-C-39012 for details). Defective connectors can be replaced but it is recommended the work be performed at a Fluke Calibration Service Center. Operating Information This section of the manual contains practical information the user needs to know before and after making a current measurement.
  • Page 20 A40B Instruction Manual Rear Front Passive Shunt (100 mA) Bottom Active Shunt (1 mA) fim005.eps Figure 2. Features and Connectors...
  • Page 21: Input/Output Connectors

    To help counter the effect, make sure the current connections are coaxial and as short as possible. A defective connector on a Current Shunt is replaceable. However, Fluke Calibration recommends the work be done at a Fluke Calibration Service Center.
  • Page 22: Maximum Current

    A40B Instruction Manual Maximum Current Each Current Shunt is marked at the input connector with its nominal (rated) current. Similarly, markings at the voltage output connector indicate the nominal voltage out for nominal current in. A table in the specifications section provides maximum currents to maintain performance and to avoid irreversible damage.
  • Page 23: Output Voltage Measurement Using A Fluke Calibration 5790B

    (ppm) (ppm) (ppm) Note The 5790B is optimized for use with the A40B shunts. For convenience, these loading values are preprogrammed into the Loading Error tables located in the shunt properties. Refer to the 5790B Operators Manual for more information.
  • Page 24: Output Voltage Measurement Using A Fluke Calibration 5790A

    Figure 3. Loading Effect of the Measurement Device Output Voltage Measurement Using a Fluke Calibration 5790A The typical input impedance of a 5790A (input 1 or 2) is >10 MΩ (dc) in parallel with 70 pF. The 10 MΩ in parallel with the shunt resistance has a small effect on the lowest current value Current Shunts at DC.
  • Page 25: Output Voltage Measurement Using A Fluke Calibration 8508A

    Precision AC Current Shunt Set Output Voltage Measurement Using a Fluke Calibration 8508A The input impedance of an 8508A on its DC function is >10 GΩ and the loading effect for measuring DC current with any Current Shunt is negligible. The typical AC function (DC coupled) low frequency input impedance of an 8508A is 1 MΩ...
  • Page 26: Operating Instructions

    A40B Instruction Manual Operating Instructions XW Warning To prevent possible electrical shock, fire, or personal injury, remove circuit power before you connect the Product in the circuit when you measure current. Connect the Product in series with the circuit. Introduction This section of the manual describes how to measure both AC and DC current using any one of the Current Shunts.
  • Page 27 Specifically it tests 200 mA at 1 kHz, as documented in the 5730A's full verification procedure. Source: Fluke Calibration 5730A – 200 mA output at 1 kHz. Measurement Equipment: Fluke Calibration Current Shunt, 200 mA (calibrated at 23 °C) and a Fluke Calibration 5790B.
  • Page 28: Direct Read-Out When Measuring Current

    For Example: In the following scenario, a current source operating at a given frequency is measured with a 100 mA Current Shunt and a Fluke Calibration 8508A. Assumptions: •...
  • Page 29: Coaxial Shunts

    Precision AC Current Shunt Set Theory of Operation Coaxial Shunts The coaxial shunts are especially designed for low-inductance. The design is similar to that developed by Mendeleyev Institute, St Petersburg. The key components of the coaxial shunts are the printed circuit board (PCB) construction and the precision resistive elements.
  • Page 30: Boxed Shunts

    Neither of the descriptions contains detailed step by step procedures for calibrating the Current Shunts. Rather, the descriptions are meant to provide a foundation for the seasoned calibration technician to work with and use the Fluke Calibration method of calibrating Current Shunts.
  • Page 31: Potential Voltage Measurement Devices

    (draughts, heat source) Fluke Calibration 792A AC-DC Transfer Standard The Fluke Calibration 792A can be used to make AC-DC difference measurements and has many advantages over the SJTVC. See Table 10. It does, however, have one disadvantage that reduces its usefulness for this application.
  • Page 32: Dc Considerations

    160 Ω. The Reference Shunt is also a 10 mA Current Shunt, but its voltage is measured with a Fluke Calibration 792A, 700 mV range – input impedance more than 10 MΩ. The entire 10 mA current generated by the source passes through the Reference Shunt.
  • Page 33: Ac Considerations

    SJTVC (160 Ω) is beneficial in this respect; it swamps the capacitance. Devices with active input circuits generally have high input resistance and capacitance becomes more influential on frequency flatness. Tables 5, 6, and 7 provide typical values and errors for Fluke Calibration 5790A, 5790B, and 8508A. Ref Std Shunt...
  • Page 34: The Fluke Calibration Method

    A comparative measurement is made to calibrate resistance at nominal current. TVC assy Clarke -Hess model 8100 Keithley 2182A Ref Std Digital Shunt SJTVC Nanovoltmeter TVC assy Keithley 2182A Digital Fluke Shunt SJTVC Nanovoltmeter 5730A feh018.eps Figure 7. The Fluke Calibration System...
  • Page 35: Recommended Tools And Equipment

    Nanovoltmeter 1 TVC assy Keithley 2182A Digital SJTVC Nanovoltmeter 2 feh020.eps Figure 8. Calibrating Gain Difference The Fluke Calibration 5730A produces an output of 0.8 V. The relative AC-DC difference of the SJTC assemblies is measured and applied as a correction.
  • Page 36: Tvc Sensitivity Characterization

    A40B Instruction Manual TVC Sensitivity Characterization The voltage output of a SJTVC output is proportional to the square of the applied voltage. Thus the device is inherently non-linear and transresistance gain or sensitivity changes with input current. Sensitivity characterization minimizes the resulting errors by determining mean sensitivity in a narrow band ±500 ppm from...
  • Page 37: Uut Ac-Dc Difference Measurement Sequence And Calculations

    Precision AC Current Shunt Set Theory of Operation UUT AC-DC Difference Measurement Sequence and Calculations In order to minimise the effects of drift, the measurement sequence is symmetrical in the form AC1, +DC, -DC, AC2. The ±DC measurements cancel thermal emf and zero offset. The two AC measurements compensate for drift during the measurement.
  • Page 38: Current Source Dc Noise

    = Gain sensitivity of the Reference Standard measurement system Current Source DC Noise From some transconductance amplifiers, noise on DC can be problematic. The Fluke Calibration system addresses this problem by triggering the two nanovoltmeters at the same time so they integrate simultaneously to maximize noise immunity.
  • Page 39: Repair Procedures Including Disassembly And Reassembly

    Table 14. Read the Safety Information earlier in this manual before replacing the batteries. All other repair and/or parts replacement should be performed at a Fluke Calibration Service Center. See How to Contact Fluke Calibration earlier in this manual to find the location nearest you.
  • Page 40: List Of Tools Required For Repair

    (Excessive heat buildup under load may indicate damage or wear.) If replacement of an LC connector is necessary, have the work performed at a Fluke Calibration Service Center. List of Tools Required for Repair A list of the tools required for disassembly, repair, and reassembly follows: •...
  • Page 41: Input N-Type Connector Replacement (Coaxial Shunts)

    Precision AC Current Shunt Set Repair Procedures Including Disassembly and Reassembly To remount or replace the removed components, logically reverse the removal procedure. feh008.eps Figure 11. Exploded View of a Shunt Input N-type Connector Replacement (Coaxial Shunts) Use the following procedure to replace the type-N input connector: 1.
  • Page 42 A40B Instruction Manual feh010f.eps Figure 12. N-Type Input Current Connector...
  • Page 43: Output N-Type Connector Replacement (Coaxial Shunts)

    Precision AC Current Shunt Set Repair Procedures Including Disassembly and Reassembly Output N-Type Connector Replacement (Coaxial Shunts) Use the following procedure to replace the N-type output connector: 1. Remove the output end plate (Figure 11-  ). 2. Remove the 3 mm screws, nuts and washers from the N-type connector. 3.
  • Page 44: List Of Replaceable Parts

    List of Replaceable Parts User service is limited to replacing the parts identified in Figure 14 and listed in Table 14. To order replacement parts refer to How to Contact Fluke Calibration earlier in this manual. Figure 14. Final Assembly – Typical Current Shunt from the Set Table 14.

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