4800p016 propeller shaft earthing system
TRANSCRIPT
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8/8/2019 4800P016 Propeller Shaft Earthing System
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Propeller Shaft Earthing System
PES advantages are : +
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high efficiency silver tracked basic system
remote indicator for permanent supervision
continuous protection of propeller and bearingsat moderate costs
patented continuous slip ring cleaning device
Constant contamination of silver surface increasesthe risk of spark erosion due to bad contact.Usually the system must be checked every weekfor cleanliness.Due to low staff and high work load theSlip ring Cleaning Device preventsincrease of the residual potential and keeps PESin safe condition over long time.
onboardcontinuously
The effectiveness ofPES must continuously becontrolled to keep the propeller protected.The remote indicator displays permanently by atwo-coloured display about the present conditionof the system.
PES protects the exposed propeller and the shaftbearings against spark erosion damages.High efficiency silver tracked slip rings and provencontact brushes ensure a short circuit between
,the rotating propeller shaft and the ships hull.Several tests in the past indicate that only thismaterial combination ensures a repeatable low
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PES serves for a short circuit between the rotating propeller shaft and the ship's hull.PES can prevent the micro pitting marks at the propeller, on the sliding surfaces of crankshaft journals
and main bearings of the engines to be assumed as spark erosion.PES ensures an excellent potential decomposition and the contact brushes ensure lubrica and long life.
Special features are:a remote indicator system in order to achieve a continuous control the effectiveness of the wholesystem
an continuous slip ring cleaning device to prevent an increase of the residual potential during operation
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Energie - Umwelt - Beratung e. V.- Institut -
JOWA
JOWA ABwww.jowa.se
JOWA AB, Tulebo 865, S-428 34 KALLERED, Goteborg, S weden
tel. +46-31 795 00 40, fax. +46-31 795 45 40, e-mail: [email protected]
GermanyJOWA GERMANY GmbH
Butzower Str. 1AD-18239 HOHEN LUCKOW
tel. +49-3829574115fax. +49-3829574141
e-mail: [email protected]
NetherlandsJOWA MARINE B.V.
Ringdijk 510 BNL-2987 VZ RIDDERKERK
tel. +31-180416067fax. +31-180466250
e-mail: [email protected]
ChinaJOWA (SHA) MARINE EQUIPMENT CO., LTD.
5111 Luo Shan Road, Pudong New AreaSHANGHAI 201204
tel. +86-2168944890
fax. +86-2168927550e-mail: [email protected]
SingaporeJOWA (S) PTE., LTD.
26, Lo rong G Telok KurauSINGAPORE 426195
tel. +65-68728802
fax. +65-68728896e-mail: [email protected]
NorwayJOWA NORGE A/S
P O Box 2281 StromsoN-3003 DRAMMENtel. +47-32236700fax. +47-32236701
e-mail: [email protected]
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Technical Information
A turning propeller shaft on a ship becomes electrically insulated from ship hull by the lubricating oil film inthe bearings and by use of non-metallic bearing materials in the tail shaft. When the shaft is insulated in this wayan electrical potential can be measured between the turning propeller shaft and the ship hull and this canaccelerate corrosion in the ship.
If the ship as a system of cathodic protection, whether it is sacrificial anodes or an impressed current system, theshaft insulation will prevent the propeller and the boss from receiving protection.The electrical potential between shaft and hull can also cause a heavy current to flow in bearings whenthe oil film breaks down or is contaminated with seawater.This current can cause deep pitting of the bearing surface. Excessive wear on the shaft bearings canoften be traced to this cause.Trouble can be avoided and cathodic protection extended to the propeller if the shaft is properly earthed with ashaft earthing system. The effectiveness of the system should ensure a maximum contact resistance of nogreater than 0,001 ohms for water filled bearing and 0,01 ohms for an oil filled bearing.
- Propeller Shaft Earthing System