Marine Radar Electromagnetic Environmental Effects (E ³ ) on Shipboard and Land-Based Adjustable Speed Drive Operation: Problems and Solutions

Field site instances are described where a ship or coastal water radar operation, near an on-ship or land-based adjustable speed drive (ASD) crane, caused random software code redundancy check (CRC) faults. The “Radar Noise Characteristics” section characterizes a wide range of radar source emission possibilities in terms of allocated radar frequency ranges IEEE S band (3 GHz) or IEEE X band (8–12 GHz), peak pulsed power variability (6- to 60-kW peak), and V/m (volts per meter) magnitude at the antenna surface. The “Radar Antenna Coupling ­Mechanisms” section describes antenna coupling mechanisms from antenna surface to V/m magnitude seen at separated ASD distance. At these frequencies, even small holes in standard ASD grounded metal cabinets allow unattenuated emission internally. Indeed, every opening in the control room door resulted in an immediate CRC trip. Separate research testing, simulating radar high E-fields at unshielded control boards, verified radar operation as the root cause of CRC faults. Existing International Electrotechnical Commission (IEC) Radiated Electric Field Susceptibility requirements for land-based ASD only extend to 2.7 GHz and have V/m specifications much lower than those for powerful radar fields in proximity. When standards do not cover unique applications, they are classified as electromagnetic environmental effects (E3) events. The “Use of Far Field Shielding Formulas” section reviews shielding effectiveness formulas and techniques to use to calculate dB V/m (voltage level in decibels reference to 1 V/m) attenuation levels required at the board level that eliminates radar source issues. The “EMC Hardened Solution Summary” section ends with a lesson learned summary on how to modify existing standard drive cabinets using an electromagnetic compatibility (EMC) hardened solution checklist on shielding materials and techniques.