Applications Guide, April 2001
Published by Fluke Corporation
This section provides easy-to-do measurements which you can perform almost anywhere. Begin with these examples to get started with the Fluke 43B.
Note: It is a good idea to reset the Fluke 43B before you start a new application. This way, you always start from the same setup.
Measuring Line Voltage
Determine whether the voltage level, voltage waveform, and frequency from an outlet are correct.
- The rms voltage should be close to the nominal voltage, for example 120V
- or 230V.
- The waveform should be smooth and sinusoidal.
- The frequency should be close to 50 or 60 Hz.
- The Crest Factor CF is an indication of the amount of distortion. A high Crest factor means high distortion.
Note: Nominal voltages and frequencies differ by country.
Determine how the current from an outlet is supplied to a load, in this example, a hair dryer.
- When the hair dryer is turned on, the current from the outlet increases.
- Notice that without test leads connected, the Fluke 43B measures the frequency of the current signal.
Line Voltage and Current Simultaneously
Measuring Line Voltage and Current
Determine the influence of the load current on the voltage.
- The rms voltage should stay within reasonable limits.
- The current increases when the copier is warming up or making a copy.
Note: In stead of a copier, you can also use other loads of 1000W or more.
Recording Line Voltage and Current
By recording the voltage and current, you can establish a possible relation between the two. For recording voltage and current, always use SAGS & SWELLS. Basically it does the same as the RECORD key, but it can record faster fluctuations. Use the RECORD key for all other combinations of readings you want to record.
Use the copier again and proceed as follows:
Choosing shorter recording times makes it easier to see details of events on the screen.
1.In this example, the high peak current from the copier caused the voltage to drop (voltage sag).
In general, if you find voltage sags, the next step is to look for devices which may cause them. Poor connections or long conductors increase the effect.
Check whether a fuse is broken or open by checking continuity. In general, you can check any circuit for open connection.
- When the Fluke 43B beeps and shows a beep-icon, the fuse is closed.
- When the Fluke 43B shows OL (Over Load), the fuse is open.
Note: When the resistance is high (>30Ω), an open circuit is indicated, otherwise the circuit is considered to be closed (0 – 30Ω).
Measure the resistance of a relay coil (or a resistor)
- Observe the resistance. A typical reading on the display should be between about 150 and 500Ω. If the reading seems too high, test a known good device and compare the measured values of both devices.
Measure the capacitance of a capacitor (≤ 500 μF).
- Observe the capacitance. The display shows the measured value of the capacitor. Compare the measured value with the value indicated on the capacitor.
Testing a Diode
Check a diode in both forward direction and reverse direction. Useful for checking whether the diodes in a rectifier are still intact
- Observe the voltage in forward direction (A). It should read about 0.5V. Now turn the diode in reverse direction (B) and look at the display again.
- The Fluke 43B should display OL (Over Load), indicating a very high resistance. If not, the diode is faulty and should be replaced