During normal operation, the gas-filled pole tube of th […]
During normal operation, the gas-filled pole tube of the automatic high-frequency welding equipment is turned on when the anode potential is higher than the cathode potential. In actual work, reverse conduction often occurs. That is, when the cathode potential is higher than the anode potential, the anode current appears opposite to the normal working current. This kind of failure of the inflatable two-switch tube is called reverse arc. The strange current that appears during the reverse arc is called the reverse arc current. The back arc is caused by the ability of the anode to emit electrons.
Since the full-automatic high-frequency welding equipment adopts an oxide cathode, the supply voltage of the cathode must be stable during normal operation, otherwise the service life of the tube will be affected. This is especially true when the anode voltage is close to the rated value. The ambient temperature refers to the actual temperature directly measured at the bottom of the tube 10 cm away from the glass bulb. It must be preheated before operation. This is because the mercury pressure is very low at room temperature and it is difficult to start an arc. After preheating, the density of mercury molecules increases and the air pressure increases, which is conducive to arc ignition.
In addition, the preheating of automatic high-frequency welding equipment can help the mercury and other substances on the anode to volatilize, so that the anode can be kept clean and avoid back arc phenomenon during work. Generally preheat for about 15 minutes. After transportation or long-term storage, the preheating time should exceed 30 minutes. When cutting off the power, the anode voltage must be cut off first, and then the filament voltage.