Reduction Gearboxes

High operation flexibility from customized gearboxes

Our wide range of gearbox configurations makes our assortment one of the most extensive in the market

Advantages with Brunvoll gearboxes

Brunvoll design team have taken advantage of decades of interaction and innovation together with the most demanding customers throughout the entire maritime cluster. This has given us valuable experience, in order to apply the right design criterias and development of module-based ships' gearboxes with respect to their functions and strength.

All materials used in the gearboxes are carefully selected to secure the optimum conditions of the product, and to obtain life-long durability and safe operations;

  • Gearboxes for a high number of operational modes
  • Flexible design with several PTO/PTI configurations
  • Part of an integrated Propulsion System
  • High quality in materials and a robust design
Brunvoll Reduction Gear Design

Unique flexibility with module based design

On all gearboxes without an integrated PTO/PTI solution it is possible to choose amongst a wide range of PTO/PTI modules which may be connected to the main gearbox.

The modules are selected by definition of the function of the gearbox and the propulsion system, and might be primary or secondary driven with our without integrated clutch solutions for fully automatic operation.

  • All Brunvoll gearbox designs are based on modules giving a unique flexibility.
  • Ideal for hybrid systems with multiple engine configurations.
  • Wide range of Power take-off (PTO) and Power take-in (PTI) units.
  • Each gearbox is configured to each customer's requirements.
  • All gearboxes are designed in 3D, and FEM/FMEA analysed in order to secure strenght and reliability.

Integrated Propulsion Systems with PTO / PTI Configurations

Brunvoll Propulsion System with PTI/PTI type SA

Single-in Single-out propulsion system with clutch + PTO type SA without clutch

  • This system contains a secondary driven PTO for shaft generator, where the PTO always runs when the propeller is running.
  • The system can also be used as a PTI with el-motor.

Single-in Single-out propulsion system with clutch + PTO type PF without clutch

  • This system contains a primary driven PTO without clutch, and is always running with the main engine.
  • The PTO can be used for generators or for pumps.

Single-in Single-out propulsion system with clutch + PTO/PTI type PF with clutch

  • This system contains a primary driven PTO with engine release clutch.
  • The PTO can run independently of the propelller.
  • Usually used for generators or for PTO/PTI solutions where the generator also can operate as el-motor.

The Brunvoll gearbox program

Size Vertical Offset Horizontal Offset Coaxial Offset Power Range kW*
ACG 450 x x x 900 - 1700
ACG 480 x 1200 - 1900
ACG 525 x 1100 - 2200
ACG 600 x x x 1800 - 3500
ACG 680 x x x 2200 - 4400
ACG 750 x x x 2500 - 5200
ACG 850 x x x 3000 - 6000
ACG 950 x x x 3700 - 6700
ACG 980 x x 3700 - 10500
ACG 1080 x x 4500 - 13000
ACG 1130 x x 4500 - 15000
ACG 1200 x x 5000 - 22000
ACG 1400 x x -> 20000
ACG 600K x 1800 - 5200
ACG 680K x 1800 - 5200
ACG 750K x 2500 - 5200
ACG 850K x 3000 - 6000
ACG 950K x 3700 - 6700
ACG 980K x 3700 - 10500
ACG TS 800 x x 2x 700 - 1500
ACG TS 1000 x 2x 1100 - 2200
ACG TS 1100 x 2x 1500 - 3000
ACG TS 1250 x 2x 2200 - 7000
ACG TS 1400 x 2x 3700 - 10000
Larger gearbox sizes
on request
ACG 680 2SP x 2200 - 4400
ACG 750 2SP x 2500 - 5200
ACG 850 2SP x 3000 - 6000
ACG 980 2SP x 3700 - 10500
ACG 1080 2SP x 4500 - 12000
Brunvoll standard gearbox range. Other configurations can be supplied on request.
The power range given for each gearbox is approximately and depends on selected
engine and propeller RPM, and also on eventual ice notation.

Gearbox range

Extensive range of vertical or horizontal offset, twin-in single-out, 2-speed, and special designed gearboxes

Starter characteristics

Direct On-Line starter

Starting current:

5-10x Nominal motor current (IN)

Pros:

Low price and high starting torque

Cons:

High in-rush current

Description:

The Direct On-Line (DOL) starter consists of a contactor and a protection device such as a circuit breaker. The contactor is energized when the start button is pressed, and the full line voltage is connected to the motor. Motor is started with propeller in zero pitch position (IZP).

Click the images to enlarge

Star-Delta starter

Starting current:

2-3x Nominal motor current (IN)

Pros:

In-rush current reduced with approx. 60% compared with DOL

Cons:

Reduced starting torque

Description:

The star-delta starter method applies reduced voltage to the motor, thus reducing current, during startup. This method requires that both ends of motor winding terminals are available. When connected in star each winding has less voltage (1 / √3 ~ 60%), and thus will have reduced starting current and torque. When full speed is reached the motor is connected in delta, having full torque available. Propeller pitch can be increased, and load applied when motor is connected in delta. Motor is started with propeller in zero pitch position (IZP).

Click the images to enlarge

Auto-Transformer

Starting current:

2-3x Nominal motor current (IN)

Pros:

In-rush current reduced with approx. 60% compared with DOL

Cons:

Reduced starting torque

Description:

Auto-Transformer also applies reduced voltage in steps to the motor during startup. The transformer voltage ratio can be designed to the application, typically having a 50-70% motor voltage during startup. The motor consumes less current at a lower starting voltage. For example, with a 50% tap on the Auto-Transformer, the motor draws half its rated current, or about 25% of what it would draw with a DOL starter. Motor is started with propeller in zero pitch position (IZP).

Click the images to enlarge

Electronic soft starter

Starting current:

2-2,5x Nominal motor current (IN)

Pros:

In-rush current reduced 

Cons:

Reduced starting torque.
Based on electronics

Description:

An electronic soft starter is a starting device that controls the way electricity is provided to the motor by using active switching devices such as thyristors. The device works in both in-line and in-delta configuration modes in three-phase motors. 

This starting method is ramping up the motor voltage in the starting sequence resulting in a reduced start-up current, allowing for a smooth and surge-free increase in motor torque. The voltage dips, stress, and wear and tear on the mechanical parts are all reduced as a result. Due to the thyristors there will be harmonic distortion of the current, and the influence on system voltage will depend on starting current and system impedance. Motor is started with propeller in zero pitch position (IZP).

Click the images to enlarge

Frequency converter starter

Starting current:

0,5x Nominal motor current (IN)

Pros:

In-rush current reduced.
Full speed and torque control

Cons:

THD generated, filters required.
Based on electronics

Description:

This is an electronic-controlled approach for starting asynchronous motors smoothly. It controls the frequency and current for the motor with electronics inverter circuits, avoiding large startup current. The thruster system's mechanical parts will be protected from high load because of the smooth start-up, and the this will also reduce the load on generators during startup compared to line-starter options. Depending on required performance torque and current may be below nominal values during startup. This is the high-end solution for the starting the thrusters, giving benefits such as smooth start, better energy economy, reduced wear and tear and process optimization.  Other benefits include motor speed stability during load changes and a longer motor life overall. Motor is started with propeller in zero pitch position (IZP).

Frequency converter starters may have different interface towards the main switchboard where 6-pulse rectifier is the most common, but both 12/24 pulse and Active Frontend (AFE) are used.6-pulse starters are the most common type, widely used due to the compact design and availability.The disadvantage with the 6-pulse starter is the increased THD during startup, particularly in smaller power system with large thrusters this might be an issue. 

To mitigate the THD a 12 or 24 pulse transformer and rectifier may be chosen, typically used for larger thrusters in larger ships. 
Frequency converter starters with active front end guarantees sinusoidal current and does not require a transformer. The AFE rectifier and LCL filter is more spacious than the 6-pulse rectifier and is suitable for high end solutions and ships with relatively small power system compared to thruster power.

Click the images to enlarge
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Technical Information

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References

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Contact

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Vidar Liaskar

Vidar Liaskar

VP Sales, Brunvoll Volda AS

+47 952 57 129
vidar.liaskar@brunvoll.no
Per Endre Woldsund

Per Endre Woldsund

Sales Manager, Brunvoll Volda AS

+47 905 72 814
per.woldsund@brunvoll.no
Arnfinn Brautaset

Arnfinn Brautaset

Sales Manager, Brunvoll Volda AS

+47 915 77 678
arnfinn.brautaset@brunvoll.no
Kirsti Gjørvad

Kirsti Gjørvad

Senior Sales Manager, Brunvoll Volda AS

+47 916 29 430
kirsti.gjorvad@brunvoll.no

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