What are the advantages of brushless AC generators for Marine Diesel Generators over traditional brushed generators?

Traditional brushed generators rely on physical contact between carbon brushes and rotor collector rings to transfer current, and carbon brushes will wear out due to friction during operation and need to be replaced regularly. The brushless generators for Marine Diesel Generators use silicon rectifiers and rotating pole structures to replace the brush system, completely eliminating the mechanical wear of carbon brushes and collector rings, achieving "zero contact" current transmission, and theoretically no maintenance of carbon brush components is required. For example, the KLG series brushless generators extend the maintenance cycle to more than 10,000 hours through brushless excitation technology.
The rotor magnetic field of the brushless generator is directly powered by the rotating rectifier, avoiding the problem of arc erosion of carbon brushes under high current. The DelStar series brushless generators use high-temperature resistant insulation materials (H-class insulation) and a closed cooling system. They can operate continuously at an ambient temperature of 55°C, and their lifespan is 3-5 times longer than that of brushed generators.
Traditional brushed generators cause additional energy loss due to brush contact resistance and commutation sparks, and the overall efficiency is usually 85-90%. The brushless generator achieves precise excitation through an electronic controller, reducing energy loss in the transmission link, and the efficiency can reach 92-95%. For example, the ship's shaft-belt brushless double-fed system can maintain voltage and frequency stability when the main engine speed changes through vector control technology, and the overall fuel consumption is reduced by 12-15% compared with auxiliary engine power generation.
The brushless generator is equipped with AVR and capacitor regulation technology, the steady-state voltage adjustment rate can reach ±0.5%, the recovery time is shortened to milliseconds, and it supports 300% instantaneous short-circuit current shock. In contrast, the voltage fluctuation rate of the brushed generator is usually ±2-3% due to mechanical commutation delay.
The marine brushless generator adopts IP23 protective housing, 316L stainless steel fasteners and vacuum varnishing process, which can resist salt spray and humid environment corrosion. Its spark-free characteristics (no carbon brush arc) meet IMO explosion-proof requirements and are suitable for hazardous areas such as tankers. Because there is no mechanical commutation friction, the running noise of the brushless generator is 10-15 decibels lower than that of the brushed machine.
Although the initial purchase cost of a brushless generator is 30-50% higher than that of a brushed generator, its maintenance-free feature can save an average of $500-2000 per year in carbon brush replacement and labor costs. Taking a 40kW marine unit as an example, the total cost of a brushless generator over a 10-year life cycle is 40% lower than that of a brushed generator. The ship's shaft-belt brushless double-fed technology can save 60,000 tons of standard coal equivalent (tce) of fuel per ship per year and reduce CO₂ emissions by 160,000 tons by recycling the redundant power of the main engine. If promoted to the global fleet, it is expected to reduce the total carbon emissions of the shipping industry by 3-5%.