# Dynamic Test Measurements and Simulation on a Series Wound DC Motor
## 3 Measurements
### Dynamic Test Measurements
#### 3.2.2 Comparison of Measured and Simulated Results  
In Reference [11] and Section 3.2.1, all the input parameters and characteristics were determined that are necessary to run the simulation for the SWDCM (Figure 2). The value of loading torque (\(M_{load}\)) was zero during the test measurements, thus it was also chosen to be zero in the simulation program. In Figures 8-11, the results of the first stage (when the rotor is spinning up from rest) of the test measurements and simulations are compared at different mechanical loads applied on the rotor.  
\begin{table}
\begin{tabular}{c c} \hline
**Load** & \(M_{res}\) **[Nm]** \\ \hline Disc 1 & 0.6075 \\ Disc 2 & 0.5925 \\ Disc 3 & 0.5976 \\ Disc 4 & 0.5747 \\ \hline \end{tabular}
\end{table}
Table 4: Friction torques obtained from the run-out experiments (\(J_{r}=0.01987\) kg\(\cdot\)m\({}^{2}\)).
Figure 8: _Cont_.  
Figure 8: Results of dynamic test measurement and simulation performed on the analysed SWDCM. (\(I_{load}=0.0001576\) kg\(\cdot\)m\({}^{2}\)). (**A**) Battery terminal voltage, (**B**) motor speed, and (**C**) current intensity.  
Figure 9: _Cont._  
Figure 9: Results of dynamic test measurement and simulation performed on the analysed SWDCM. (\(I_{load}=0.0018561\) kg\(\cdot\)m\({}^{2}\)). (**A**) Battery terminal voltage, (**B**) motor speed, and (**C**) current intensity.  
Figure 10: Cont.  
Figure 11: _Cont._  
Figure 10: Results of dynamic test measurement and simulation performed on the analysed SWDCM. (\(J_{load}=0.0035496\) kg\(\cdot\)m\({}^{2}\)). (**A**) Battery terminal voltage, (**B**) motor speed, and (**C**) current intensity.  
On the basis of Figures 8-11, it can be stated that in the initial short time period, the values of angular speed and current intensity are increasing rapidly. After that, the current intensity reaches its maximum value (between 170-250 A depending on the loading moment of inertia on the rotor) in the form of a sharp peak and then approaching a constant value of about 20 A. After the initial intensive increase, the angular speed of the rotor gradually approaching its top speed, at higher values of loading moment of inertia, this process is significantly more slowly than at lower ones.  
Figure 11: Results of dynamic test measurement and simulation performed on the analysed SWDCM. (\(J_{load}=0.06785\) kg\(\cdot\)m\({}^{2}\)). (**A**) Battery terminal voltage, (**B**) motor speed, and (**C**) current intensity.  
Considering the percentage error of the electric resistance of the shunt resistor (0.5%) and the one of the measured voltage by the NI 9239 module (0.3%), the estimated percentage error of the measured electric current intensities and angular speeds is less than 1%. It must be emphasised that wire heating can introduce additional error in the measured values of current intensity.  
The measured and simulated functions are in a good agreement, which confirms that our simulation program works properly, and the dynamic and electromagnetic parameters of the motor were measured accurately. At lower loading moment of inertia (0.000158-0.003549 kg\(\cdot\)m\({}^{2}\)), the percentage of accuracy of the simulated angular speeds relative to the measured one is varied between 98-99% while at higher moment of inertia (0.06785 kg\(\cdot\)m\({}^{2}\)) is between 96-99%. In case of the current intensities, at lower loading moment of inertia (0.000158-0.003549 kg\(\cdot\)m\({}^{2}\)), the percentage of accuracy of the simulated current intensity relative to the measured one is varied between 93-98% while at higher moment of inertia (0.06785 kg\(\cdot\)m\({}^{2}\)) is between 94-99%.