Alaska Diesel Electric, Seattle, Wash., has been building small heavy-duty marine and industrial generator sets since 1963. To meet increasing demands for high quality electrical output they have developed a new generator called the PXK line. This generator will first be featured in the new model M843JK gen-set rated 10 kW. A three-cylinder, water-cooled Lugger diesel drives the newly designed generator at 1800 rpm and the unit is also available at 8 kW for 1500 rpm, 50 Hz/240 V output.

This year, several other models utilizing the new generator end are also being introduced, including 8, 12, 16, 20 and 32 kW (1800 rpm/60 Hz ratings) marine and industrial sets.

A key design objective was to increase performance without increasing generator set length. Alaska Diesel engineers reported that the new generator design has actually decreased overall generator set length in several configurations. For example, length of the 8 kW model has gone from 35.2 in. to 32.5 in.; the 12 kW set from 38.1 in. to 36.6 in.; and the 20 kW set from 47.7 in. to 43.4 in.

New design features include the addition of more copper throughout the generator to increase efficiency and motor starting capability. The additional copper also holds temperature rise to 95 [degrees] C to extend generator life in high heat environments such as inside sound shields housed in relatively small engine rooms.

The generator rotor includes a shaft, large sealed beating, an easily accessible rotating rectifier, a large diameter exciter rotor and main rotor. The rotor exciter and stator are totally hot dipped in epoxy insulation for protection against the marine environment. Wiring is all Class H insulated. The skewed, angled groove stator design is hand-wound by experienced manufacturing personnel and produces electricity with a clean and symmetrical wave form for precise electric power, high electrical efficiency and motor starting, Alaska Diesel said.

The stator is mounted in a strong, rolled steel generator frame with machined ends to mate with the cast iron bearing housing and SAE flywheel adapter ring. The bearing housing is cast iron for strong corrosion resistance and a thermal expansion rate that more closely matches the bearing on the rotor. A large diameter cooling fan is cast into the drive member, increasing airflow for better cooling and reduced fan noise.

An important service feature is that the exciter stator housing and bearing housing can be removed for easy access without removing the rotor or generator from the base. All the new K series ends are SAE 4 compatible, except the 8 kW unit, which is SAE 5 compatible. In the new 10 kW marine diesel generator set, single-phase electrical output is standard, with three-phase optional.

Another significant improvement is the automatic voltage regulator (AVR). The solid state circuitry has been modified to provide better wave form control and excellent protection for sensitive electronics and electric motors.