2-speed Gearboxes

The Brunvoll 2-speed gearbox is a fully integrated reduction gearbox that provides two propeller speed steps in hybrid or diesel-mechanical controllable pitch propulsion. It suits vessels with varying power demand and reduces fuel consumption at low propeller rpm.

Operating principle

• Step 1: the main engine drives the propeller through the main gear ratio while the shaft generator is driven via the PTO gear set – for high propeller demand and low electrical demand
• Step 2: the main engine drives the propeller through the PTO gear and on through the PTI gear set and main gear, giving lower propeller rpm while the engine runs at nominal speed – for lower propulsion demand combined with high shaft generator output
• Suitable for configurations with main-engine power generation to the main switchboard, and for hybrid systems requiring boost, Power Take Home (PTH) and/or diesel-electric mode

Design

• Gear housing in high-quality grey cast iron with high stiffness and good vibration damping; nodular cast iron optional (typically for high ice class)
• High-precision gears optimised for high load, low vibratory excitation and long life
• Sliding bearings for journal and thrust bearings
• High-capacity, hydraulically operated, multiple-disc, oil-lubricated clutches
• Designed in 3D and analysed at full load; fulfils all class society requirements

Technical data

| Size | Offset | Power range (kW)* |

|---|---|---|

| ACG 680 2SP | Vertical | 2200 – 4400 |

| ACG 750 2SP | Vertical | 2500 – 5200 |

| ACG 850 2SP | Vertical | 3000 – 6000 |

| ACG 980 2SP | Vertical | 3700 – 10500 |

| ACG 1080 2SP | Vertical | 4500 – 12000 |

*Power range depends on selected rpm and any ice notation.

Applications

Purse seiners, trawlers, AHTS, seismic vessels, mega yachts and rescue vessels. On the pelagic vessel Odd Lundberg, trawling in step two with 50–60 Hz floating frequency reduced fuel consumption by 100–130 litres per hour.