DP MAINTENANCE TRAINING

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Timothy Gordon
5 years ago
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1 DP MAINTENANCE TRAINING SINGAPORE

2 Topics Day 2 Review Introduction to Serial Communications Serial Interface Cards Using the Workstation Diagnostics Screens Practical Applications Discussion of AMC

3 Topics Day 3 Introduction to Different Types of Thrusters Thruster Interfacing, Control and Feedback Signals, Measuring Equipment Introduction to Wago PLC, Maintenance Computer Practical Applications Introduction to Networks, IP Addressing, AMC Converteam P80-Pilot, Isagraf Software, Downloading Files to Components

4 DP MAINTENANCE TRAINING THRUSTERS

5 Main Elements Sensors and Thrusters Anemometer DGPS Artemis DP Control Computer Gyrocompass Laser Reference Vertical reference unit Propellers Tunnel Thruster Taut Wire Position Measuring System Acoustic Positioning System Azimuth Thruster Tunnel Thruster Rudders Weight Acoustic Transponder

6 Tunnel Thruster

7 Azimuth Thruster

8 Swing Down Thrusters

9 Cycloidal Voith Schneider

10 Water Jet Control Flaps Thrust out Jet Impeller Water flow in

11 Types of Thruster

12 White Gill Jet Direction Drive Impeller Drive Directional Thrust Water inflow

13 Main Propeller and Rudder

14 Adjustable Plate Directed Thrust Moment

15 Balancing Prop Forces Water Flow from Propeller gives counteracting thrust for Prop 1 forward moment Propeller 1 (Fwd mode) Propeller 2 (Astern Mode) Directed Thrust Moment Water Flow passing rudder gives forward moment

16 Different types of thruster Variable speed, fixed pitch direct drive diesel through gearbox and slipping clutch, electric VFD & SCR. Variable pitch, fixed speed (CPP) direct drive using diesels, electric drive with hydraulic pitch control. Azimuthing thrusters can be both the above normally use hydraulic steering motor. Often used as main propulsion, bow thrusters often retractable or swing down type.

Thruster Interface +24V DIGITAL INPUT AVAILABLE FOR DP SYSTEM HEALTHY PUMPS RUNNING DP MODE ANALOGUE OUTPUT REFERENCE/DEMAND COMMAND THRUSTER / PROPELLER / RUDDER ANALOGUE INPUT FEEDBACK

17 Thruster Interface +24V DIGITAL INPUT AVAILABLE FOR DP SYSTEM HEALTHY PUMPS RUNNING DP MODE ANALOGUE OUTPUT REFERENCE/DEMAND COMMAND THRUSTER / PROPELLER / RUDDER ANALOGUE INPUT FEEDBACK FEEDBACK DP SYSTEM THRUSTER CONTROL SYSTEM OR PROPELLER / RUDDER The reference/demand and feedback could each be up to 4 signals for one thruster. For example: PITCH, SPEED, AZIMUTH SINE, AZIMUTH COSINE.

18 Thruster Interface The DP system will send a reference ( 10V or 4-20mA) to the thruster only if the available signal is present and the thruster has been selected A thruster will become deselected only if the operator deselects it or if the available signal is lost. Loss of the available signal means either a loss of the digital input (e.g. a wire falls off, a relay contact opens, the DP s 24V fails) or loss of communication between outstation and control console / control cabinet (e.g. loss of outstation power, network problems). The DP control software assumes that the reference is being followed by the thruster if the thruster is available to the DP. The feedback signal ( 10V or 4-20mA) is completely ignored by the control software. Feedback is used only for display and for raising feedback fault alarms.

19 Thruster interfacing There are normally at least two feedback potentiometers, one to the DP and one to the thruster controller. There are thrusters on the market (Rolls Royce) which control both the pitch and speed of the propeller through a combi control, the amount of thrust is computed in the Rolls Royce controller Where propeller speed is controlled (Fixed pitch, variable speed propellers) RPM sensors are used instead of pitch angle feedback. Prime movers may be hydraulic through electric pumps, electric (either DC(SCR) or AC (VFD)) using DC or squirrel cage motors, or direct drive diesel engines via a gearbox and clutch.

20 Thruster interfacing VFD prime movers may interface directly to the DP system using CANbus or Ethernet connection. Azimuth thrusters require some means of steering the propeller, normally two hydraulic motors preferably supplied from either side of the switchboard. Azimuth angle feedback is provided by sin/cos potentiometers or encoders. Feedback to the DP may be sin/cos +-10V = or 4 to 20mA = 0-359

21 Thruster interfacing sin/cosine potentiometer

22 Thruster interfacing Pitch control is performed using hydraulic solenoids, proportional valves or stepper motors to increase or decrease pitch. In CPP propellers there will be a zero pitch interlock to prevent the thruster being started when the pitch blade is not at zero degrees.

Offshore Hydromechanics Module 1

Offshore Hydromechanics Module 1 Dr. ir. Pepijn de Jong 6. Real Flows part 2 Introduction Topics of Module 1 Problems of interest Chapter 1 Hydrostatics Chapter 2 Floating stability Chapter 2 Constant