The DC-plasma voltage is the key parameter of plasma spraying. It is important to adjust and control the plasma voltage correctly during the complete spraying process. Most equipments on the market are not able to measure the plasma voltage between the anode and cathode. Because the measurement are influenced by cable losses and other effects. Therefore not the real DC-plasma voltage in real is indicated, a circumstance not to be tolerable in the quality control.
Our True Voltage Controller is directly fixed on the Plasmatron and supplies a proportional voltage signal from 0 – 10 V-DC according to the real plasma tension in the range from 0 up to 100 V-DC, depending on the existing torch. The length of the burner cables and dynamically changing cable losses are now excluded from the DC-plasma voltage measurement.
To increase the plasma energy and enthalpy, a secondary plasma gas is needed (H2, N2). Beside the rise in DC-plasma voltage a much higher emission of noise is produced due to the plasma arc characteristic. High arc voltage fluctuations are responsible for the increase of the sound level but also influence the DC-voltage measurement. Only a true root mean square amplifier (TRMS) can detect the DC-plasma-voltage with overlapped voltage fluctuations and indicate it as true DC-value.