Fluke A40B Instruction Manual
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A40B
Precision AC Current Shunt Set
Instruction Manual
July 2008 Rev. 1, 7/09
© 2008-2009 Fluke Corporation. All rights reserved. Specifications are subject to change without notice.
All product names are trademarks of their respective companies.
LIMITED WARRANTY AND LIMITATION OF LIABILITY
Each Fluke product is warranted to be free from defects in material and workmanship under normal use and
service. The warranty period is one year and begins on the date of shipment. Parts, product repairs, and
services are warranted for 90 days. This warranty extends only to the original buyer or end-user customer of
a Fluke authorized reseller, and does not apply to fuses, disposable batteries, or to any product which, in
Fluke's opinion, has been misused, altered, neglected, contaminated, or damaged by accident or abnormal
conditions of operation or handling. Fluke warrants that software will operate substantially in accordance
with its functional specifications for 90 days and that it has been properly recorded on non-defective media.
Fluke does not warrant that software will be error free or operate without interruption.
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. Fluke reserves the right to invoice Buyer for importation costs of
repair/replacement parts when product purchased in one country is submitted for repair in another country.
Fluke's warranty obligation is limited, at Fluke's option, to refund of the purchase price, free of charge repair,
or replacement of a defective product which is returned to a Fluke authorized service center within the
warranty period.
To obtain warranty service, contact your nearest Fluke authorized service center to obtain return
authorization information, then send the product to that service center, with a description of the difficulty,
postage and insurance prepaid (FOB Destination). Fluke assumes no risk for damage in transit. Following
warranty repair, the product will be returned to Buyer, transportation prepaid (FOB Destination). If Fluke
determines that failure was caused by neglect, misuse, contamination, alteration, accident, or abnormal
condition of operation or handling, including overvoltage failures caused by use outside the product’s
specified rating, or normal wear and tear of mechanical components, Fluke will provide an estimate of repair
costs and obtain authorization before commencing the work. Following repair, the product will be returned to
the Buyer transportation prepaid and the Buyer will be billed for the repair and return transportation charges
(FOB Shipping Point).
THIS WARRANTY IS BUYER'S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL OTHER
WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY
OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. FLUKE SHALL NOT BE LIABLE
FOR ANY SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OR LOSSES,
INCLUDING LOSS OF DATA, ARISING FROM ANY CAUSE OR THEORY.
Since some countries or states do not allow limitation of the term of an implied warranty, or exclusion or
limitation of incidental or consequential damages, the limitations and exclusions of this warranty may not
apply to every buyer. If any provision of this Warranty is held invalid or unenforceable by a court or other
decision-maker of competent jurisdiction, such holding will not affect the validity or enforceability of any other
provision.
Fluke Corporation
P.O. Box 9090
Everett, WA 98206-9090
U.S.A.
Fluke Europe B.V.
P.O. Box 1186
5602 BD Eindhoven
The Netherlands
11/99
To register your product online, visit http://register.fluke.com
Table of Contents
Title Page
Introduction and Specifications ......................................................................... 1
About the Manual.......................................................................................... 1
Safety Information......................................................................................... 1
General Safety Summary .......................................................................... 1
Symbols..................................................................................................... 2
Product Description ....................................................................................... 3
Electrical Specifications .................................................................................... 4
Current Shunt Absolute Accuracy................................................................. 4
Resistance Specifications .............................................................................. 5
Maximum AC-DC Difference....................................................................... 6
Maximum Overload Current ......................................................................... 6
Typical Phase Displacement.......................................................................... 6
General Specifications ....................................................................................... 7
Dimensions (maximum) ................................................................................ 7
Physical/Mechanical Parameters ................................................................... 7
Operating Environment ................................................................................. 7
Storage and Transit Environments
(for models other than the 1 mA Current Shunt)........................................ 7
Additional 1 mA Current Shunt Specifications............................................. 7
Preparing for Operation ..................................................................................... 8
Unpacking and Inspecting the Shunts ........................................................... 8
Accessories.................................................................................................... 8
Table.......................................................................................................... 8
Contacting Fluke ........................................................................................... 9
Shipping Information..................................................................................... 9
Storage Information....................................................................................... 9
Acceptance Test............................................................................................. 9
General Maintenance/Cleaning ..................................................................... 10
Operating Information ....................................................................................... 10
Feature Descriptions...................................................................................... 10
Input/Output Connectors ............................................................................... 12
Maximum Current ......................................................................................... 13
Operating Environment ................................................................................. 13
Correcting for Current Shunt Error Contributions ........................................ 13
Output Voltage Measurement – Loading Effect............................................ 14
Output Voltage Measurement Using a Fluke 5790A .................................... 14
i
A40B
Instruction Manual
Output Voltage Measurement Using a Fluke 8508A .................................... 15
Operating Instructions........................................................................................ 16
Introduction ................................................................................................... 16
Measuring Current......................................................................................... 16
Direct Read-out When Measuring Current.................................................... 18
Theory of Operation........................................................................................... 18
Coaxial Shunts............................................................................................... 18
Boxed Shunts................................................................................................. 19
Introduction ................................................................................................... 20
An Overview of Calibration Methods ........................................................... 20
Potential Voltage Measurement Devices .................................................. 21
DC Considerations .................................................................................... 22
AC Considerations .................................................................................... 23
The Fluke Calibration Method ...................................................................... 24
Recommended Tools and Equipment ....................................................... 25
System Calibration for AC-DC Difference............................................... 25
TVC Sensitivity Characterization ............................................................. 26
UUT AC-DC Difference Measurement Sequence and Calculations ........ 27
Current Source DC Noise.......................................................................... 28
UUT DC Resistance Measurement ........................................................... 28
Repair Procedures Including Disassembly and Reassembly ............................. 29
Repair Limits................................................................................................. 29
List of Tools Required for Repair.................................................................. 29
End Plates and Guard Binding Post Replacement (Coaxial Shunts)............. 30
Input N-type Connector Replacement (Coaxial Shunts) ............................... 31
Output N-Type Connector Replacement (Coaxial Shunts) ........................... 32
List of Replaceable Parts ................................................................................... 33
ii
List of Tables
Table Title Page
1. Contents of the Current Shunt Set Packaging ........................................................ 8
2. A40B Accessories .................................................................................................. 8
3. Features and Connectors ........................................................................................ 12
4. Typical Loading Effect of a 5790A, 2.2 V Range.................................................. 14
5. Typical Loading Effect of an 8508A 2 V ACV Range.......................................... 15
6. Estimating the Uncertainty of a 5790A Measurement ........................................... 17
7. Sample Calculation of Measured Current .............................................................. 17
8. Single Junction Thermal Voltage Converters ........................................................ 21
9. Fluke 792A AC/DC Transfer Standard.................................................................. 21
10. Fluke 5790A Measurement Standard ..................................................................... 22
11. Other Error Sources and Solutions......................................................................... 23
12. List of Recommended Equipment.......................................................................... 25
13. Final Assembly....................................................................................................... 33
iii
A40B
Instruction Manual
iv
List of Figures
Figure Title Page
1. Current Shunt Configurations ................................................................................ 3
2. Features and Connectors ........................................................................................ 11
3. Loading Effect of the Measurement Device........................................................... 14
4. Current Shunt - Simplified Electrical Diagram...................................................... 19
5. Circuit Using a Reference Shunt Resistor to Determine Source Current............... 20
6. Sources of Error in AC Measurements .................................................................. 23
7. The Fluke Calibration System................................................................................ 24
8. Calibrating Gain Difference................................................................................... 25
9. Characterizing Sensitivity ...................................................................................... 26
10. AC/DC Difference Sequence ................................................................................. 27
11. Exploded View of a Shunt ..................................................................................... 30
12. N Type Input Current Connector ........................................................................... 31
13. Output Voltage Connector ..................................................................................... 32
14. Final Assembly – Typical Current Shunt from the Set .......................................... 33
v
A40B
Instruction Manual
vi
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 or Current Shunts). It contains all of the information a
Calibration Technician needs to operate and maintain the Current Shunts. The manual is
divided into the following sections:
• Introduction and Specifications
• Preparing for Operation
• Operation Instructions
• Theory of Operation
• Service Instructions
Safety Information
This section addresses safety considerations and describes symbols that may appear
either in this manual or on the Current Shunts.
A
W Caution statement identifies conditions or practices that could result in damage to
the Current Shunts or equipment to which it is connected.
A X
W Warning statement identifies conditions or practices that could result in injury or
death.
To avoid electric shock, personal injury, or death, carefully read
the information under General Safety Summary before
attempting to install, use, or service the Current Shunts.
General Safety Summary
This manual contains information and warnings that must be observed to keep the
Current Shunts in a safe condition and ensure safe operation. Using or servicing the
Current Shunts in conditions other than as specified in the Instruction Manual could
compromise your safety.
To use the Current Shunts correctly and safely, read and follow the precautions on the
next few pages, as well as, the safety instructions or warnings given throughout this
manual. In addition, follow all generally accepted safety practices and procedures when
working with and around electricity.
XW Warning
1
A40B
Instruction Manual
To avoid electric shock, personal injury, fire, or death, read the following warnings
before using the Current Shunts:
• Use the Current Shunts only as specified in this manual.
• To avoid damage to eyes, skin, and the respiratory system, do not significantly
• Do not use the Current Shunts in wet environments.
• Inspect each Current Shunt before using it. Do not use the Current Shunt if it appears
• Do not use a Current Shunt if it operates abnormally. If in doubt, have the Current
• Have the Current Shunts serviced only by qualified service personnel.
• Do not use the Current Shunts with voltages above 30 V ac rms, 42 V ac peak, or 42 V
• When servicing the Current Shunts, use only specified replacement parts.
• Do not dispose of batteries in fire. Do not heat, deform, solder, dissemble or modify
• If batteries are removed from the shunt, ensure they are re-inserted with the correct
• 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
• When replacing the batteries, replace them all together. Use only Nickel Metal Hydride
• Do not operate the batteries together with other types of batteries, or batteries with
• The batteries in the 1 mA Current Shunt are always connected to the charging socket,
XW Warning
exceed the maximum current rating of a shunt. Doing so may cause tracks on the
printed circuit boards to vaporize. (See Maximum Overload Current in the Electrical
Specifications.)
damaged.
Shunt serviced.
dc. These voltages pose a shock hazard.
the batteries
polarity.
connecting it to the shunt.
(NiMH) batteries.
different charge levels.
even when the Current Shunt is turned off.
2
Symbols
The following safety and electrical symbols may appear on the Current Shunt or in this
manual.
W
F
O
Power on setting
I
Risk of danger.
Important information. See manual.
DC (Direct Current)
Power Off setting
~
:
<
J
Do not dispose of this product as unsorted
municipal waste. Go to Fluke’s website for
recycling information.
Warning. Hot or burn hazard
Recycle
Earth ground
Precision AC Current Shunt Set
Introduction and Specifications
Product Description
The A40B Precision AC Current Shunt Set consists of 14 Current Shunts, a complement
of 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. They exhibit outstanding resistance value stability, excellent self-heating
power coefficient, and a low temperature coefficient. Five configurations of Current
Shunts comprise the set. They are as follows:
• One boxed active shunt 1 mA
• Three boxed passive shunts 10 mA, 20 mA 50 mA
• Five small size coaxial shunts 100 mA, 200 mA, 500 mA, 1 A, 2 A
• Three medium size coaxial shunts 5A, 10 A, 20 A
• Two large size coaxial shunts 50 A, 100 A
The physical construction and the components used in the Current Shunts ensure that
amplitude displacement (error relative to DC resistance) and phase displacement at
100 kHz are small enough to be neglected in all but the highest accuracy measurements.
Voltage output is nominally 0.8 V for nominal current input. The 1 mA boxed active
Current Shunt is shown in Figure 1.
Input
Input
Figure 1. Current Shunt Configurations
Input
fim002.eps
3
A40B
Instruction Manual
Electrical Specifications
Current Shunt Absolute Accuracy
The following table shows the 1-year absolute accuracy specification stated at k=2, approximately 95% confidence for the
calibrated value. The specifications include 1-year stability, temperature effects over TCal ± 1 °C, and the measurement
uncertainty of the calibrated value.
Shunt Nominal
Nominal
Current
[4]
1 mA
Resistance
(Ohms)
DC 1 kHz 10 kHz 30 kHz 100 kHz
800 20 55 75 75 150
Specification ±μA/A, TCal ±1 °C, ≤50% RH
[1][2][3][5]
10 mA 80 20 26 26 26 26
20 mA 40 20 26 26 26 26
50 mA 16 20 23 23 23 23
100 mA 8 20 24 24 24 24
200 mA 4 20 26 26 26 26
500 mA 1.6 21 27 27 27 28
1 A 0.8 21 27 28 28 31
2 A 0.4 21 27 30 30 48
5 A 0.16 21 31 32 40 71
10 A 0.08 26 37 60 61 92
20 A 0.04 26 43 52 70 113
50 A 0.016 32 55 80 81 144
100 A 0.008 35 65 90 98 174
[1] The measured current is determined from:
I = (V /R
[2] Above 1 kHz interpolate the specification (s
[3] add 20 μA/A if relative humidity is outside specification limits.
[4] 1 mA specifications apply with the battery charger disconnected.
[5] Specifications assume no loading effects due to the voltage-sensing device. See
Effects
) × (1 + (AC-DC
calibrated
in the operating information.
calibrated
/ 1,000,000)); where AC-DC
) between frequencies f
i
is expressed in ppm
calibrated
and f
upper
lower
)()()(
ffssffss −÷−×−+=
lowerupperlowerupperloweriloweri
using:
Output Voltage Measurement - Loading
4
Precision AC Current Shunt Set
Electrical Specifications
Resistance Specifications
Maximum
Shunt Nominal
Current
1 mA 800 250 8.2 18 5 1
10 mA 80 250 6.8 18 2.5 1
20 mA 40 250 8.2 18 4.5 1
50 mA 16 250 8.3 18 4.5 1
100 mA 8 250 8.3 18 2.5 2
200 mA 4 250 8.6 18 3.5 4
500 mA 1.6 250 9.6 18 4.5 13
1 A 0.8 250 9.3 18 4.5 26
2 A 0.4 250 9.4 18 4.5 26
5 A 0.16 250 9.9 18 4.5 30
10 A 0.08 250 15 18 4.5 65
20 A 0.04 250 14 18 4.5 78
50 A 0.016 250 24 18 4.5 105
100 A 0.008 250 28 18 4.5 105
[1] Stability specification combines long term change due to aging (permanent) and short term fluctuation due to humidity
changes when shunts are used and stored within specified humidity limits. Add 20 ppm if humidity is >50 % RH)
[2] Assume rectangular distribution when combining with other uncertainty contributions.
[3] Calibrated resistance values include the effects of power coefficient at the nominal current. For currents other than nominal,
apply the correction for power coefficient from:
[4] TCal = ambient temperature at calibration
Nominal
Resistance
(Ohms)
Deviation
from Nominal
Resistance
(±μΩ/Ω)
Uncertainty of
Calibrated
Value at 95%
Confidence
(±μΩ/Ω) TCal
[2]
MultipliertCoefficienPowerCorrection
±1ºC
⎡
⎢
1__
⎢
⎣
12 Month
Stability
(±μΩ/Ω)
2
Applied
min
⎤
⎞
⎟
⎥
⎟
⎥
alNo
⎠
⎦
I
⎛
⎜
−×=
⎜
I
⎝
[1][2]
Temperature
Coefficient
(±ppm/ºC)
[2]
Coefficient
Multiplier
(±ppm)
Power
[2][3]
5
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