Twin-In Single-Out Gearboxes

Flexibility, Redundancy, Efficiency, Reliability - The gearbox is the heart in a propulsion configuration that makes it all possible.

The Twin-In Single-Out gearbox is a gearbox for high flexibility in propulsion system configurations. Multiple options for engine solutions with or without PTO/PTI units.

A propulsion system ready for the future

  • Flexible system designed for the possibility of a high number of oprational modes
  • Hybrid system prepared for multiple engine and energy sources
  • Efficient power distribution from a wide range of power input and power output (PTI/PTO)
  • Compliant with all types of future energy sources
  • Compatible with all engine makes
  • Configured to your specific needs and operating profiles
  • Part of a Brunvoll Integrated Propulsion and Manoeuvring System
  • High quality in materials and a robust design
Brunvoll Propulsion System with Propellers and shaftline, TS800 gearbox, Tunnel thrusters and Control System, in a configuration with gensets, electric motors, VFDs, batteries and main switchboard.
Size Vertical Offset Horizontal Offset Coaxial Offset Power Range kW*
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 size on request
Standard Brunvoll gearboxes.
* The power range for each gearbox depends on selected rpm and eventual ice notation.

Configuration flexibility

The wide range of twin-in single-out gearboxes allows for numerous configurations. The gearboxes may be used in a single propeller shaft, or as a twin-screw system. Compatible with all energy types and power sources, and we configure the system according to your specific needs.

Ideal for all applications requiring configuration flexibility by power from different energy sources, or requirements for wide power range power in a wide operating profile;  

  • Ro-Pax
  • Offshore vessels
  • Fishing vessels
  • Aquaculture - Live Fish Carriers
  • Anchor Handling Tug Supply vessels
  • Patrol Vessels
  • High power cargo vessels

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

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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Vidar Liaskar

Vidar Liaskar

Sales Manager, Brunvoll Volda AS

+47 952 57 129
vidar.liaskar@brunvoll.no
Arnfinn Brautaset

Arnfinn Brautaset

Sales Manager, Brunvoll Volda AS

+47 915 77 678
arnfinn.brautaset@brunvoll.no
Per Endre Woldsund

Per Endre Woldsund

Sales Manager, Brunvoll Volda AS

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

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