KONGSBERG SR/SV Steering Servo Maintenance Comprehensive Guide

Monthly: Clean the servo compartment and surrounding environment, test all control consoles (including emergency and normal steering), check steering time according to SOLAS, check the blockage indicator of the dual filter, check the coupling between the pump and motor, and ensure that the control panel indicates normally.

Quarterly: Conduct alarm system function testing according to the manual.

Every six months: Conduct internal leak testing, collect hydraulic oil samples from actuators, and replace filters.

Every year: Check the alarm logs of the frequency converter, test the communication system between the servo and the cab, conduct insulation tests on the motor (Megger test), and inspect the electrical components and grounding connections.

Chapter 5: Core components - Steering actuator

The core of SR/SV type servos lies in their unique actuator design. It adopts a cylindrical rudder, with blades/pistons working inside a spherical rotor centered on the rudder. This design allows the blades to adapt to rotor spherical deflection caused by installation deviations or rudder deflection. Synthetic bearing gaskets can maintain 100% surface contact, absorb and suppress vibration and shock pulses, and are continuously lubricated by hydraulic oil.

Important notice: To access the lower seal and bearing gasket, it is necessary to lift the rotor. Prior to this, it is necessary to securely lock the rudder blades and prepare the lifting equipment. Kongsberg is not responsible for fixing the rudder blades, which is entrusted to the shipyard or a suitable third party by the shipowner.

Chapter 6: Power Unit - Motor, Pump, and Valve Block

SR/SV servos can be configured with two main hydraulic power systems:

Variable frequency pump system (FCP):

Design feature: Two reversible pump units controlled by frequency converters are used. The motor only starts when receiving the rudder command and stops when it reaches the command position.

Working principle: Under normal circumstances, when a single pump is running and both pumps are running simultaneously, the steering speed doubles. The pump unit consists of a reversible pump, a motor, and a bell shaped housing with an elastic coupling.

Valve block integration: The integrated valve block has fewer and simpler valve components due to the use of reversible pumps. Including one-way valve, load control valve, electromagnetic isolation valve, safety valve, and return oil filter, etc.

Conventional pump system:

Design features: Equipped with an independent pump unit, the pump operates continuously, and the oil is controlled by the steering valve. The pump unit includes an oil tank with a base, a steering valve, a return oil filter, and a vane pump (or gear pump) with an elastic coupling. The motor is connected to the top plate through a flange.

Pipeline connection: The pump unit needs to be connected through three pipelines: two to the distribution valve of the actuator and one to the oil tank.

Chapter 7: Detailed Explanation of Core Maintenance Programs

This chapter is the practical core of maintenance work, covering the most critical technical operations.

7.1 Inverter Error Log

Check that the cooling air duct of the frequency converter is unobstructed and free from dust cover.

Ensure that the cover plate is properly secured.

View through the alarm log button on the local control panel, navigate using the directional keys, and all events are timestamp based on running hours.

7.2 Hydraulic oil recommendation - crucial

Warning: Using fluids not specified by Kongsberg may result in vessel maneuvering malfunctions, causing personal injury and equipment damage.

Attention: Hydraulic oil is the main component and should not be mixed with other oil products. The performance of the servo is highly dependent on the viscosity of the oil, and the selection must take into account the ambient temperature.

Standard: It shall meet DIN 51524 standard, pour point shall be lower than -30 ° C, and it must have anti-wear, water resistance and foam resistance characteristics.

Recommended brands: The manual provides a detailed list of models from multiple manufacturers, such as Shell Tellus S2 VX 32、Mobil DTE 10 Excel 32、BP Bartran HV 32、Statoil Hydraway HVXA 32 Etc., as well as biodegradable types.

Oil change indicator: When laboratory testing shows an increase in neutralization value, low residue of extreme pressure additives, an increase in insoluble particles, and oil cleanliness below ISO 4406 standard 17/14 or NAS 1638 standard level 8, it must be replaced.

7.3 System oil quantity

The manual lists the approximate oil quantities of different models (SR562 to SR743, SV430 to SV850) under variable frequency pump and conventional pump configurations. For example, the SR722 variable frequency pump system requires approximately 125 liters, while the SR722 with PU50 pump system requires approximately 450 liters.

7.4-7.6 Oil level inspection and oil sampling

Oil level: If the liquid level gauge on the expansion tank shows oil, it indicates that the oil level is normal. Long term unchanged oil level indicates no leakage.

Sampling: It is necessary to use chemically pure oil bottles and perform highly clean operations. The sampling point is usually located on the upper housing, rear of the valve block, or on the filter housing. Rinse the sampling tube during operation, mark and compare the new oil immediately after sampling.