3000W Chinese Gensets Info.

Salvo wrote:

This issue brings back memories of a large caliber machine gun problem I was called on to fix. After the gun was operated in burst mode for a minute or so, it would all of a sudden start shooting at full speed while the trigger had no control of stopping the gun. To make a long story short, the trigger activated a relay which activated a solenoid that initiates the shooting. The solenoid has a large inductance. Once current flows through an inductor, the inductor will do everything in its power to maintain that current even when the relay wants to turn the current off. As the relay contacts start to open, the solenoid generates an extremely large voltage that's large enough to ionize the air gap between the relay contacts. Current will continue to flow until the relay contacts have moved far enough apart. The spark that keeps current flowing heat the contacts. A succession of firing bursts create enough heat to weld the relay contacts together, resulting in an uncontrollable gun. The fix was to add a capacitor between the relay contacts. As the contacts opened, current continues to flow by way of the capacitor.