Navigation:  Tutorials > Power module tutorials > Single phase power measurement > DEWESoft 7.0  data acquisition, processing, analyzing and storage software Channel setup

So let's measure the line voltage and the current with a current clamp, calculate the power and connect some loads like our old hair dryer, a classic light bulb and an energy saving light bulb.

 

We will use the same setup for analog channels like in the "Voltage and current" example. So the first channel is the voltage while the second channel is the current.

 

Note that we need to have the correct unit for voltage and current. Voltage units could be V, kV and MV while the current units could be either A or kA.

Now we go to the Power module tab and create one power module by clicking on the  +  button. First, we click on the Power system configuration drop down list, selecting the Single phase configuration and defining the voltage and current channels. We select U for voltage and I channel for current. Then we select the Line frequency. In Europe, the common line frequency is 50 Hz, in the US 60 Hz and in large vehicles like ships, it is common to have 400 or 800 Hz. We can also measure the frequency inverters when selecting variable Frequency source.

Next, we need to check the vector scope to see if everything is connected correctly. It is right there on the setup screen. First thing to notice is that the voltage and current are opposite. Since we don't have a generator, but a hair dryer connected, we can assume that we are measuring the current in the wrong direction.

 

We can solve this by reversing the voltage plugs or turning around the current clamps, but there are cases where this is not as easy. If we have used current transformers which can't be opened, it is the best to change the polarity in the software. Let's go back to the setup for current. To reverse the polarity is easy - just enter a negative "scaling factor" instead of a positive one. So10 V measured actually means -10 A on the input (and -10 V means +10 A).

 

Let's go back to make sure everything is ok. Now the phase angle is approximately 10 degrees, which seems reasonable.

Now let's see which channels are available. Basic parameters like frequency or power channels (P, Q, S, phi, cos phi) will be added automatically. So if we only want to measure basic power parameters, we don't have to select anything.

If we want to have additional parameters, we can choose to calculate the Harmonics, but even if we don't choose them, the values will be still available in the harmonic FFT and the vector scope. The only difference is that we can't, for example, show the 3rd harmonic of voltage in the recorder display. I have also chosen to select the THD, Period values and the Flicker.

 

Now let's make a measurement.