Operating Instructions; Introduction; Measuring Current - Fluke A40B Instruction Manual

A40B
Instruction Manual

Operating Instructions

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. The procedures are based on the
assumption that the user is familiar with the Operating Information and
Specifications presented earlier in this manual.

Measuring Current

Use the following procedure to measure current using one of the Current Shunts:
1. Analyze the circuit being tested and determine the following:
2. Select a Current Shunt capable of safely handling the estimated current.
3. If using the 1 mA Current Shunt, switch it to On and verify that the battery low
4. Remove power from the circuit under test and connect the input of the
5. Connect an appropriate voltage measuring device to the output of the Current
6. Apply current to the circuit and measure the resulting output voltage. This
7. Use the voltage measurement and the Operating Information in the previous
18
a. The approximate value of the current that flows in the circuit.
b. The frequency of the current to be measured (DC to 100 kHz).
(red) indicator is off. If the 1 mA Current Shunt has been charging, disconnect
the charger. The charging process creates heat in the battery so for the best
accuracy allows the shunt temperature to stabilize for 100 minutes after
charging completes.
Current Shunt in series with the circuit.
Shunt, and select the correct range. The output voltage of the Current Shunt
is proportional to the input current; 0.8 V for nominal rated current.
It is generally appropriate to set the measuring device to remote guard and
connect its guard terminal to the guard on the Current Shunt. Refer to the
measuring device documentation.
output voltage is directly proportional to the current flowing in the circuit.
section of this manual to accurately determine the current level.
Determine the current using the following formula:
Where: AC-DC calibrated and Loading error are expressed in ppm.
 

V
   
= × 
I
R

 
calibrated
XW Warning

AC - DC
+  ×
calibrated
1
1,000,000

 
Loading error
 − 
1
1,000,000
 