# The Use of Wireless Networks and Mobile Applications in the Control of Electric Machines
## 5 The Use of Wireless Transmission and Mobile Application in Control
The presented measurements show that the motor starting was at the thyristor firing angle of 90\({}^{\circ}\), while at firing angle equal to 0\({}^{\circ}\) the machine reached a speed of 2190 RPM while its supply voltage was 135 V. This value is close to the theoretical value expressed by the following equation:  
\[U_{\text{d}\alpha}=\frac{3}{\pi}\int\limits_{\frac{3}{3}+\alpha}^{\frac{2\pi} {3}+\alpha}\sqrt{2}U_{\text{p}}\sin\omega t\text{d}\omega t=\frac{3\sqrt{2}}{ \pi}U_{\text{p}}\cos\alpha=1.35\cdot U_{\text{p}}\cos\alpha, \tag{1}\]  
where:  
\(U_{\text{d}\alpha}\) is the voltage on the DC side of the rectifier, while \(U_{\text{p}}\) is the line-to-line supply voltage. The dependence of the motor supply voltage on the rotational speed is linear for almost the entire tested range. The exemplary voltage and current waveforms obtained for the firing angle of the rectifier's thyristors equal to 60\({}^{\circ}\) are shown in Figures 10 and 11, while their frequency spectra are in Figures 12 and 13. Figure 10 presents the waveforms when the motor is at idling speed, while Figure 11 shows when the motor is loaded. The voltage and current waveforms obtained during the laboratory measurements, as well as their frequency spectra, were consistent with the results achieved in the simulation tests. The signal frequency spectra did not show any impact on the wireless transmission systems, as the frequency ranges of the electrical signal were different from the ones used in the wireless transmissions. Therefore, the signals emitted by the converter did not affect the transmission of the control signals produced by the developed wireless controllers. The values of the measured motor currents were 185 mA for the motor at an idling speed and 1 A for the loaded motor. These measurements are in agreement with those displayed on the power spectrum of the system. Figure 11: Exemplary results; the firing angle equal to 60\({}^{\circ}\); motor loaded; (**a**) input current and input line-to-line voltage waveforms; (**b**) motor current and motor supply voltage waveforms. Figure 12: Frequency spectra of input current (**a**) and voltage (**b**) waveforms; the firing angle equal to 60\({}^{\circ}\); motor idling speed. Figure 13: Frequency spectra of motor current (**a**) and motor voltage (**b**) waveforms; the firing angle equal to 60\({}^{\circ}\); motor idling speed. the application screen, for which the values were 182 mA and 1.02 A. Temperatures gained by the motor and obtained through the use of the application are 23 \({}^{\circ}\)C when the motor was at an idling speed and 26 \({}^{\circ}\)C when it was loaded. The operation of wireless communication in a remote-control system was tested in dependent of the distance between a mobile device and a PMDC motor drive and its supply. During testing, other machines placed in the laboratory were under operation to obtain conditions similar to those prevailing in the production hall. Bluetooth and Wi-Fi were tested at the following distances from the object: 3, 7, and 11 m. Such values were chosen on account of the practical utilization of such a system, as well as the visibility of the object as it cannot be out of sight. Long-distance control would require the introduction of an object's visual preview, for instance from a camera. The most significant indicators of the proper operation of the control system are presented in Table 4.