Fault phenomenon: After the equipment is started, when the power rises to a certain value, the equipment is easy to over-current protection action, sometimes the thyristor component is burned out and restarted. The phenomenon remains the same.
Fault analysis and processing are as follows.
a. If an overcurrent is easily generated at a low voltage immediately after startup, the inverter lead angle is too small to cause the inverter thyristor to be reliably turned off.
b. The water-cooling jacket of the inverter thyristor has a reduced water or heat dissipation effect, and the water-cooling sleeve is replaced. Sometimes it is sufficient to observe the water output and pressure of the water jacket, but often due to water quality problems, a layer of scale is attached to the wall of the water jacket, because scale is a very poor thermal conductivity material, although there is sufficient water flow. However, because of the segregation of scale, the heat dissipation effect is greatly reduced. The method of judging is: running the power at a power lower than the overcurrent value for about 10 minutes, and stopping quickly, and quickly touching the core of the thyristor element by hand after stopping, if the hand feels hot, the fault is the cause. caused.
c. The connection line of the tank circuit has poor contact and disconnection. Check the connection line of the tank line and handle it according to the actual situation. When there is poor contact and disconnection in the connecting line of the tank, the fire will rise after a certain value rises, which will affect the normal operation of the equipment, resulting in equipment protection. Sometimes a transient overvoltage occurs at both ends of the thyristor due to a fire. If the overvoltage protection action is too late, the thyristor component will burn out. This phenomenon often occurs when overvoltage and overcurrent occur simultaneously.
