 Hi, my name is Thomas Ressler and in this part I'd like to introduce to you how to measure practically the motor parameters. The first measurement we need to make about the motor is to record the resistance of the windings. For that I will use a standard multimeter with the ohm range but because this motor has a very low impedance I'll need to zero our measurement. So first let's take the probes and short circuit them using the relative function of the multimeter which now is used as a reference for the measurement of the resistance of the windings. Well, I will connect the windings, wait for the stabilization and we can read the impedance or resistance of one of the windings of the motor. If we want to check that the value is correct between all three phases we can as well try the measurement on other, wait for the stabilization and this way the measurement is finished. Right now we will measure the number of pole pairs. For that we will require a power supply with a presentable current limitation. So let's use this one and let's choose the current limit at one amp. We can afford up to a nominal current of the motor but beware that we will work in a DC mode so the motor can start heating very quickly. Now let's connect the supply between two phases of the motor and let's turn the output on. Now the motor will emit the DC electromagnetic field in its stator where the rotor will try to snap to it. So it's very important to choose a proper current so that I can feel only the torque between the positions while if I reach the positions where the rotor is fixed and aligned to the stator field it doesn't move and it has the lowest torque available. So let's count how many stable positions we can reach around one mechanical rotation. So now I can feel one and when I move it 180 degrees apart is another position. I'll try to verify and again I can return back to the initial position which means we have only two stable positions around one mechanical rotation. This gives us a total of two pole pairs for this motor. Our next measurement will be an inductance of the windings. So let's choose two of them and let's use a RLC meter like this one to measure the inductance. True, let's connect it here and we can read that the inductance between the two terminals is 5.2 micro Henry. However, this is not an end of this measurement because depending on the motor type we can identify two types one with inset permanent magnets and typically with the trapezoidal shape of the electromagnetic force or we can find the one with a sinusoidal shape where we will see only one inductance over the whole range. So to be able to distinguish between these two types of motors we have to measure the inductance on different angles of the rotor. This is why I will slowly turn it and always wait for the stabilization and I can read that the maximum value of the inductance is 6.4 micro Henry and the minimum inductance is 4.6. This will again a record in our spreadsheet and use for the further setup of the FOC library. The next part of the measurement of the motor will be the electrical constant. To measure it we need to record the voltage and the frequency of the output, the inducted voltage from a spinning motor. To help ourselves I took the aqua drill and connected it on the shaft of the motor. So you can see the motor mounted here, the aqua drill and the connection of the two phases straight to the probe connected to our digital oscilloscope. So let me spin it and record the measurement. Ok now I have stopped my measurement and we can look on the screen and measure the shape. What is important for us it is to record the frequency of the measurement and the amplitude expressed in volts peak to peak. Because there is a lot of noise inducted we will use cursor of the oscilloscope to measure the voltage. So let me choose one of the shapes, the one in the middle and read the peak to peak voltage which is in this case 438 millivolts. At the same time we can read the frequency of the measurement which is 24.55 hertz. Now we will record it and use it later in the spreadsheet. Well after the measurements let's fill the measured values into the spreadsheet I have prepared to make the preparation of the data for the motor control workbench a little bit easier. Let's begin with a number of pole pairs, if you remember well we measured two. Now let's come back to the resistance and this one we have read as 0.01 ohm. Be careful here we have measured resistance between the two terminals of the motor which takes two windings or two coils in a series. Now let's choose the biggest of the inductances which we measured as 6.4 microhenry. The lowest one was 4.7 microhenry. And finally let's come back to the record of our oscilloscope with a measured frequency of 24.55 hertz and 0.4383 millivolts. With these data we are almost ready to fill in the spreadsheet. However there are some parameters that we are not able to measure physically so we have to refer to the datasheet of the selected motor or use our experience. The blue motor I have chosen, the maximum rated speed is 20000 rpm, the nominal current is 8 amps, the magnetizing current is typically the same like nominal but can be a little bit different and the nominal voltage for this motor is 32 volts. Finally we have all the data and you can notice that the spreadsheet chose the permanent magnet synchronous motor with inset magnets. It calculated the one winding resistance as 5 milli ohms, chose two pole pairs, the rated speed we have read in the datasheet, nominal current and DC voltage as well. It calculated the LQ and LD plus their ratio, the magnetizing current and finally it calculated the electrical constant Ke. With these values we can now come to the motor control workbench and fill in the motor parameters.