Relay Contact Weld Detection Using Controlled Electrical Pulses

The patent applies preliminary action by performing weld detection checks during relay system startup and before critical operations. The controller executes test sequences that apply controlled voltage pulses to relay coils and measures resulting current flows to detect welded contacts before they cause catastrophic failure. This proactive detection approach allows the system to identify and flag potentially welded relays before they fail during normal operation.

The patent replaces mechanical/physical inspection methods with electrical measurement techniques. Instead of physically examining relay contacts or using complex mechanical testing apparatus, the system uses electrical pulse application and current flow measurement to detect welded contacts. The controller applies voltage pulses and measures current characteristics (magnitude, rise time, decay) to infer contact weld status, substituting electrical sensing for mechanical detection.

The patent applies parameter changes by systematically varying voltage pulse magnitude, duration, and waveform characteristics to optimize weld detection while protecting the relay coil. The controller adjusts pulse parameters based on relay ratings and detection requirements, using higher magnitudes briefly for detection then returning to normal operating levels. This dynamic parameter adjustment enables precise weld detection without causing damage or false positives from excessive energy application.

The patent implements periodic action by applying voltage pulses in controlled, intermittent sequences rather than continuous high-magnitude signals. The detection process uses brief pulse applications followed by measurement intervals, allowing the relay coil to remain in safe states between detection attempts. This periodic pulsing pattern enables repeated detection checks while ensuring the coil receives sufficient rest time to avoid thermal or electrical damage from cumulative energy exposure.