Monitoring
Index Introduction... 2 Components...3 Functional Description... 6 Features... 8 Standard Monitoring Functions... 9 Alarm Definition... 9 Technical Data...11 Miscellaneous...13 Applications...16 Examples... 20 Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 1 / 22
Introduction The Geislinger Monitoring GMS Mark4 (4 th generation) is an instrument designed to continuously monitor the torsional vibration amplitudes e.g. of a reciprocating internal combustion engine. The main advantages of the Geislinger Monitoring are: Optimum operation of the engine due to early detection of problems. Monitoring of a damper/coupling to determine the exact condition of the damper/coupling before an engine overhaul or dry docking. If the evaluation of the measurements shows that the damper/coupling is working properly, it can be justified in front of the classification society, that no overhaul is necessary. Should an overhaul be necessary it can be planned and the spare parts can be ordered in time. Reduction of maintenance cost and time during dry docking or engine overhaul. Increased life of the GMS Mark 4 monitored installation with longer inspection intervals. Easy to use for torsional vibration measurements Geislinger quality and worldwide after sales service Power Monitoring with high accuracy The system gives an alarm signal when safety limits are reached or exceeded, it also indicates engine speed and operating hours. Furthermore, it can measure torsional vibration amplitudes, analyze the results and transmit them to a PC. Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 2 / 22
Components The Geislinger Monitoring consists of three main components: Digital sensors Junction Box System Unit System Unit Sensor 2 Outer part Junction Box Sensor 1 Inner part Fig.1 General arrangement of components Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 3 / 22
Digital Sensors The measurement is usually achieved with digital sensors of an inductive type, which are mounted in a fixed position and measure against rotating wheels with teeth. If no such wheels are available, the use of angular encoders is also possible. Junction Box At the Junction Box, the cables of all sensors are formed into a single cable which leads to the System Unit. The signals from the sensors are converted and transmitted to the System Unit. System Unit The System Unit contains a LCD display, three alarm lights, four push buttons and a printed circuit board equipped with a microprocessor which calculates primarily the phase velocity of rotating elements. By means of measurements from one or two torsionally vibrating elements (e.g. on a coupling or damper), the values of the static and dynamic twist between the elements as well as the vibratory angle of the elements are calculated. The calculated torsional vibration values and other parameters are shown on the LCDdisplay as a graph or as FFT analyzed values. The power supply for the Geislinger Monitoring and the alarm outputs (relay and analog outputs) for e.g. a ship control system are at the rear of the System Unit. A serial communication port RS232 for measurements and programming is also included in the System Unit. Cabling All cables are supplied by the customer. This includes also the cable between System and Junction Box. The cables must be approved by the classification society. Between System Unit and Junction Box, Geislinger recommends a cable with a common copper screen, 6 conductors in pairs, each conductor with a minimum cross section of 0.5 mm². Unit Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 4 / 22
General Arrangement of the Components The sensors are equipped only with short cables to avoid distortion of the signal. Therefore the Junction Box has to be placed close to the sensors (max. distance = 1.7m). The Junction Box can be mounted directly on to the engine or damper housing by welding the mounting plate to the engine or damper housing and screwing the Junction Box on the plate. The System Unit is normally placed in the engine control room. For dimensions of installation openings and mounting holes see chapter. ( Technical Data ) System Unit Junction Box Sensors Cabling Installed in the engine control panel in the engine control room Close to sensors (max 1.7m), can be mounted directly to engine or damper housing Adjustable inductive sensors installed in fixed position with brackets inside the damper housing, bracket with inspection hole and oil tight cable gland. All cables are supplied by the customer. This includes also the cable between System Unit and Junction Box. The cables must be approved by the respective classification society. Between System Unit and Junction Box Geislinger recommends a cable with a common copper screen, 6 conductors in pairs, each conductor of a minimum cross section of 0.5 mm². Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 5 / 22
Functional Description Display and Buttons LED s LCD display area push buttons cover of serial communication line Fig.2 Front of System Unit The System Unit has 4 push buttons and 3 LED s. monitoring function no. 1 area for alarms monitoring function no. 2 monitoring function no. 3 area for messages Fig.3 Display description engine speed operating hours; values in decimal format: 3.50 = 3 hours 30 minutes Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 6 / 22
Monitoring Function number of monitoring function name of monitoring function minimum value (bar graph) bar graph maximum value (bar graph) actual value (unit is milliradian) WARNING LOW limit (if defined) WARNING HIGH limit ALARM limit Fig.4 Description of a Geislinger Monitoring function Normal Operation The Geislinger Monitoring is starting up automatically after electrical power is connected. During operation the readings are taken from the sensors and processed simultaneously. The computed values of the monitoring functions are shown both as numbers and as bar graph on the display. Depending on the engine speed, the system reads the appropriate limits from the memory and compares these values with the ones computed. The limits are also shown in the bar graph. If a value is over a warning or alarm limit the following happens: On the right side of the screen the monitoring function, a warning or an alarm will appear. The corresponding relay output is opened. The corresponding LED is illuminated. Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 7 / 22
Features In the following section some features of the Geislinger Monitoring are described. Signalcurve Shows the torsional vibration signal for each programmed application per one revolution. Fourier Shows the amplitude of the different orders for each application after a FFT (Fast Fourier Transformation) analysis. Fig.5 Signal curve graphics Info Submenu Contains general information about the programmed monitoring functions and current serial communication line settings. The programmed alarm curves are also shown in a graphical mode. Serial Communication Line RS232 for Connection to a PC The Geislinger Monitoring is equipped with a standard RS232 communication interface located on the front of the System Unit. It is possible to transmit measured and analyzed values to a PC for further calculations. At the PC the values can be recorded with a simple terminal program, which is included in every Microsoft Windows software. The graphic evaluation of the recorded values can be carried out by a standard spreadsheet like Microsoft Excel. Fig.6 Fourier graphics Fig.7 Programmed alarm curves Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 8 / 22
Standard Monitoring Functions Free End Total This monitoring function shows the synthesis of the vibratory angle at the free end of the crankshaft. Reduction in power, cylinder failure or cylinder misfiring influence the vibratory angle at the free end of the crankshaft. For this monitoring function the sensor signal is acquired directly from the crankshaft or damper inner part (damper inner part is bolted to the crankshaft). Free End Filtered This application calculates the vibratory angle of a single order or a range of orders out of the synthesis of the vibratory angle at the free end of the crankshaft. In many propulsion systems only a specific order, or a range of orders caused by torsional vibrations is responsible for critical shaft, crankshaft or intermediate shaft vibratory stresses. Monitoring the amplitude of this order is a proper method for detecting dangerous operating conditions. For this monitoring function the same sensor signal as in monitoring function Free End Total is used. Damper Twist Shows the vibratory twist angle between damper inner part and damper outer part. This application controls the damper load. Dysfunctional oil supply or heavy wear of the damper springs leads to an increased vibratory twist. This will activate an alarm on the Geislinger Monitoring. A blocked damper with no vibratory twist causes also an alarm, because other parts of the propulsion system (e.g. crankshaft, intermediate shaft) are overloaded if the damper does not work. Monitoring of the damper is also very useful for determining the exact condition of the damper before an engine overhaul or drydocking. If the measurements show that the damper is working properly, it can be justified in front of the classification society, that no damper overhaul is necessary. In the case that spare parts are needed they can be ordered in time. Alarm Definition After the CPU has calculated the vibratory angle or vibratory twist, the results are evaluated against limit curves. Limit curves are defined as continuous lines with a maximum of 20 supporting points. Each point is defined by its coordinates. The unit of the x coordinate is rpm (or the static twist in case of coupling monitoring), the unit of the y coordinate is milliradian. It is possible to monitor only a part of the speed range. The WARNING LOW curve is normally only defined for monitoring of damper or coupling twist. To avoid nuisance alarms, an actual alarm is triggered only if several alarm points occur in sequence. This number of sequential alarm points is defined in the setup. If an alarm is activated, usually a Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 9 / 22
message appears on the display, a LED is illuminated on the display and an alarm relay is activated. For special applications the Geislinger Monitoring can be programmed in a way that warnings or alarms from certain monitoring functions are not connected to the relay output. Levels may sometimes exceed the WARNING limit because of abnormal engine handling, but this should not be the normal condition. ALARM limits must not be reached or even exceeded. WARNING LOW curve actual calculated value Warning limit WARNING LOW Alarm limit IDEAL FIRING WARNING HIGH ALARM normal operating graph operating range not monitored permissible operating range Fig. 8 Alarm definition Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 10 / 22
Technical Data Specifications Permissible ambient temperature System Unit Junction Box Inductive sensors 55 Celsius (131 F) 70 Celsius (158 F) 100 Celsius (212 F) Power supply Voltage: 24V DC 20% Maximum current consumption: 1 Ampere Technical standards Electrical and environmental testing according to IACS E 10 rules and type approval from DNV Outputs 4 relay outputs (max. 24 VDC, 1 Ampere) 1 analogue output (4.. 20 ma) 1 serial communication line RS232 Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 11 / 22
Dimensions and Weights System Unit 192 x 147 mm, (approx. L x W = 7.6 x 5.8 ) approx. 135 mm deep (5.3 ) (including space for cables at rear) weight: 1.5 kg (3.3 lbs) 8 x 45 182 134 135 Installation depth: outer dimensions of System Unit: 192 x 147 mm 135mm M 4 179 Fig.9 Assembly opening for System Unit Junction Box 130 x 130 mm (Approx. L x W = 5.1 x 5.1 ) (including space for cable glands) 60 mm high (2.4 ) weight: 0.6 kg (1.3 lbs) Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 12 / 22
Miscellaneous What are Torsional Vibrations? Torsional vibrations are the result of pulsating, dynamic torques of a reciprocating combustion engine and the propeller. All system components like crankshaft, intermediate shaft, propeller shaft and optional couplings and gears have to transmit the static torque and the additional vibratory torque. The Geislinger Monitoring monitors the torsional vibrations. Torsional Vibration Terms order... vibration frequency divided by speed synthesis... summary of single orders FFT... Fast Fourier Transformation frequency analyzed vibration Description of Signal Processing A sensor mounted on a fixed position measures against a rotating toothed wheel. Instead of a sensor also an angular encoder supplying a digital signal can be used. The encoder can be mounted on the front end of a wheel or shaft. The signal of the sensor switches from low output to high output when a tooth passes the tip of the sensor. The signal is the elapsed time (pulse duration) between one tooth and the next tooth (see Fig. 10). The measured pulse duration is proportional to the angular velocity. A microprocessor records the signal of the last ten revolutions. On demand this sample of ten revolutions is used for further signal processing. sensor sensor signal t1 t2 t3 t4 t5 t high low Fig.10 Signal processing Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 13 / 22
A plot of time over angle yields a graph shown in Fig.11. The mean time between two teeth (constant angular velocity or rpm) can be subtracted. time t3 t1 t2 t4 t5 t6 t7 t8 t9 mean time between two teeth angle Fig.11 Plot of Sensor Signal To obtain the peaks of the signal, it is necessary to do oversampling (insert additional generic points). Another necessary step is to calculate from time differences to angle differences by use of the angular velocity. vibratory angle generic points t1 t2 t3 t4 t5 t6 t7 t8 t9 angle Fig.12 Signal oversampling After these calculation steps (result is shown in Fig.12) the signal passes through a bandpass filter (Fig.13). The purpose of the bandpass filter is to remove accelerations (caused by the engine speed control system) through removing low orders (below the first order in case of 2 cycle engines, below the 0.5th order in case of 4 cycle engines) and to smoothen the signal by interpreting the additional inserted points as high frequent interferences (this is necessary to obtain the exact amplitude of the vibratory angle). Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 14 / 22
Bandpass filter order vibratory angle max amplitude = (max min) / 2 angle min Fig.13 Results of signal filtering The result of the filtered values is the ±vibratory angle of the synthesis of a specified range of orders (Fig.13) depending on the filter settings. The quality of the filters allows filtering of just one order or half orders. The last step is to calculate the amplitude by: (maximumminimum)/2 of the vibratory (twist) angle and check this value against safety limits. These limits are depending on the engine speed (rpm). For explanation of alarm limits see chapter Alarm Definition. Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 15 / 22
Applications In the following catalog section the various possible Geislinger Monitoring applications are described. Free End Monitoring This option calculates the synthesis of all orders of the absolute vibratory angle of a rotating part by means of a sensor signal. Also a range of orders or a single order can be filtered. Only one sensor (inductive sensor or angle encoder) is used. Typical applications for Free End Monitoring are: Misfiring Detection The synthesis of the vibratory angle at the free end of the crankshaft indicates how smooth the Fig.14 Free End Monitoring engine is running. Misfiring of one or more cylinders of a combustion engine will cause an increase of torsional vibrations (increased amplitude of the synthesis of the vibratory angle) and may result in a damage of certain components. Shaft Stress, Crankshaft Stress or Intermediate Shaft Stress Monitoring In many propulsion systems only a specific order is responsible for critical shaft, crankshaft or intermediate shaft stresses caused by torsional vibrations. Monitoring of the amplitude of this order is a proper method to detect dangerous operating conditions. Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 16 / 22
Damper Monitoring This option includes the monitoring of the synthesis of the vibratory twist angle between two rotating parts. The two rotating parts are combined elastically. Two sensors are necessary. From the signal of each sensor the synthesis of all orders of the absolute vibratory angle is calculated. The synthesis of the amplitude of the difference between these values is monitored. Fig.15 Damper Monitoring Damper Monitoring is mainly used for: Monitoring of the vibratory twist angle between damper inner part and damper outer part is necessary for controlling the damper load. Dysfunctional oil supply or heavy wear of the damper springs leads to an increased vibratory twist. This will activate an alarm in the Geislinger Monitoring. A blocked damper with no vibratory twist causes also an alarm, because other parts of the propulsion system (e.g. crankshaft, intermediate shaft) are overloaded. Monitoring of the damper is also very useful to determine the exact condition of the damper before an engine overhaul or dry docking. If the measurements show that the damper is working properly, it can be justified in front of the classification society, that no damper overhaul is necessary. In the case that spares parts are needed, they can be ordered in time. Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 17 / 22
Coupling Monitoring Monitors the synthesis of the vibratory twist angle between two rotating parts with a static offset, caused by torque. Based on the measured static twist, computing of the transmitted torque and power is possible. The two rotating parts are combined elastically. For this monitoring function two sensors are necessary. Both rotating parts Fig.16 Coupling Monitoring must have a reference mark (a longer gap or tooth), which is used for recognizing the static offset. The torsional stiffness of the monitored part can be entered as a cubic polynom and is used for calculating torque and transmitted power. Coupling Monitoring is mainly used for: One sensor is mounted on the power input side, the other on the power output side of the coupling. Monitoring of the vibratory twist angle between coupling inner part and coupling outer part is necessary to control the coupling load. Dysfunctional oil supply or heavy wear of the Geislinger Coupling springs due to overload leads to an increased vibratory twist. This will activate an alarm in the Geislinger Monitoring System. A blocked coupling with no vibratory twist causes also an alarm, because other parts of the propulsion system are overloaded. Monitoring of the coupling is also very useful to determine the exact condition of the coupling before an engine overhaul or dry docking. If the measurements show that the coupling is working properly, it can be justified in front the classification society that no coupling overhaul is necessary. In the rare case that spares parts are needed, they can be ordered in time. Shaft Monitoring Shaft monitoring is similar to coupling monitoring. The only difference is that the stiffness of the springs is substituted by the stiffness of the shaft. The accuracy of the measured torque increases with the distance between the sensors (= length of shaft) and the data quality of the shaft dimensions. Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 18 / 22
Power Monitoring As the name indicates the system provides a reliable propulsion power monitoring. As in most ships steel shaft lines are used, the Geislinger Power Monitoring is based on twist measurement. The steel shafts in spite of their size provide certain elasticity and thus twist under engine load and torsional vibrations. The Geislinger Power Monitoring measures this behaviour via sturdy measuring gear rings and robust, reliable inductive sensors. Fig.17 Power Monitoring Precise algorithms detect the torsional vibrations and provide an exact overview of static twist the engine output and shaft line vibrations. This simple and compact concept avoids error prone radio based signal transmission as well as strain gauges. Power Monitoring is mainly used for: The Geislinger Power Monitoring is perfectly suitable for installation on existing propulsion systems as well as on new ships. It provides the master an easy tool for economic ship operation: If the speed is reduced it is possible to directly see the influence on the engine output for example 20 percent speed reduction result in almost 45% less engine power consumption. This can be directly converted into fuel savings. In such a way it is possible to optimize the overall fuel consumption. The Geislinger Power Monitoring is also suitable to effortlessly detect increased fuel consumption due to unfavourable currents or natural cover and thus enables the master to take the suitable countermeasures. This is especially important for speed controlled engines. Benefits A big bonus of the Geislinger Power Monitoring is that it not only provides a precise power measurement onboard, it additionally monitors continuously the vibration behaviour of the shaft line. As ships become more and more complex and ship staff becomes a short resource, this is a safety element which is getting more and more important. In this way critical load conditions are detected and an alarm signal is transferred to the ship alarm system. Thus damage of the propulsion system and related ship accidents can be avoided. Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 19 / 22
Examples Geislinger Monitoring used for Damper Monitoring Damper type: D 260/17 + Geislinger Monitoring Damper outer diameter: Nominal damper twist: 2600 mm 3.5 mrad This damper is designed to protect the crankshaft and therefore an important part of the main engine. Sensor 2 Junction Box Sensor 1 Fig.18 Example for Damper Monitoring Sensor 1 is mounted near the damper inner part, sensor 2 is mounted near the damper outer part. This installation is an example for the high accuracy of the Geislinger Monitoring System, because the vibratory angles are very low. In case of damper twist: 3.5 mrad; in case of free end filtered (9th order): 1.75 mrad. Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 20 / 22
Geislinger Monitoring used for Coupling Monitoring Coupling type: BE 180/22.5/126U + GFL S112 F8 + Geislinger Monitoring Coupling outer diameter: Performance data: 1800 mm 13 000 kw, 308 rpm, torque: 403 knm The combination of Geislinger Flexlink and Geislinger Coupling is mounted between an electric motor and a pod propeller unit. The system is designed to protect the pod propeller and to compensate for misalignments. Sensor 2 Sensor 1 Fig.19 Example for Coupling Monitoring Sensor 2 is mounted near the outer part of the Geislinger coupling (input of torque), sensor 1 is mounted near the outer part of the Geislinger Flexlink coupling (output of torque). Through this arrangement both couplings are monitored. Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 21 / 22
Geislinger Monitoring used for Power Monitoring The Power Monitoring is installed on ships' propeller shafts allowing the output propeller power to be monitored as part of the overall ship's fuel usage optimisation control system. Sensor 2 (turn wheel gear) Shaftline Sensor 1 (measuring gear at aft flange) Monitoring Unit optional Display Fig.20 Example for Power Monitoring Sensor 2 is mounted at the flywheel position of the engine (input of torque), sensor 1 is mounted at the measurement ring position of the propeller side (output of torque). In common the system unit is located in the engine control room. To show the monitored power also on the bridge of the vessel it is also possible to install an optional second display. Geislinger GmbH, 5300 Hallwang, Austria Monitoring Catalog: Version 5.1 September 2008 22 / 22
Geislinger Coupling Geislinger Damper Geislinger Gesilco Geislinger Flexlink Geislinger Monitoring Geislinger Carbotorq Geislinger Vdamp Geislinger GmbH A-5300 Hallwang/Salzburg, Austria Hallwanger Landesstrasse 3 Tel. +43/662/669 99-0 Fax +43/662/669 99-40 info@geislinger.com www.geislinger.com
Geislinger Coupling Geislinger Damper Geislinger Gesilco Geislinger Flexlink Geislinger Monitoring Geislinger Carbotorq Geislinger Vdamp Geislinger GmbH A-5300 Hallwang/Salzburg, Austria Hallwanger Landesstrasse 3 Tel. +43/662/669 99-0 Fax +43/662/669 99-40 info@geislinger.com www.geislinger.com