Prevent high maintenance costs at an early stage
On sea-going vessels and ships, the propeller blades and propeller shaft bearings are vulnerable to spark erosion as the turning propeller shaft becomes electrically insulated from the hull. This is even the case on vessels that are equiped with sacrificial anode systems.
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In order to direct the electrical current that flows through the propeller shaft to the hull of the ship, a proper propeller shaft grounding system contains parts that have a very low electrical resistance. The main component of the Althen PSE System consists of is a copper slipring with a solid silver inlay that is supplied with two stainless steel clamping bands including dedicated connectors. Furthermore, a brush holder is supplied which holds two silver/graphite brushes (80% Ag) that run over the silver track of the slipring. The brushholder is connected to the hull of the ship by means of an earthing cable. It has been proven that this set ensures optimal electrical continuity, which reduces total cost of ownership.
In addition to our PSE system, a monitoring set can be installed in the engine room to visualize the potential difference between the propeller shaft and the hull of the ship. This system contains an additional brushholder with a single brush that runs over the silver track of the slipring. This brusholder is insulated from the hull of the ship and connected to an analog mV-meter that indicates if the PSE system is working properly. The advantage of this monitoring system is that it operates independently without the need of power supply. The analog mV-meter on the monitoring unit has a range of 0-500mV.
When the shaft earthing set is working properly, the mV-meter should indicate a value below 50mV. Exceeding the 50mV means malfunction of the PSE system, which may be related to filthy or worn parts, or incorrect installation. Additionally the monitoring set can be supplied with a 4-20mA converter that offers an additional alarm function. This function can be used to send a signal to the bridge when the potential difference becomes too high due to malfunction of the PSE system.
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We offer propeller shaft earthing systems but can also help you with further measurement solutions for the maritime industry.