The turning gear is an electrically driven system to turn the engine flywheel manually in diesel engine. It consist of a motor, gear arrangement. When engaged the gear arrangement mounts on the engine shaft gear and rotate the flywheel by about .60 RPM (it varies). it is needed for maintenance and inspection.
Electrically-driven turning device in Wartsila 20 V32 engine:
Electrically-driven turning device in engines also called turning gear to manually rotate the flywheel for inspection and maintenance. Its simply arrangement of motor and gear coupling with fly wheel. Under normal running condition, the gear is disengaged.
The engaging and disengaging of the turning gear is accomplished by the lever with yellow ball knob. The turning gear is spring-loaded outwards in order to prevent it from meshing with the flywheel when out of operation.
Precautions using turning gear arrangement
The turning device is provided with a start blocking valve which prevents starting if the turning gear is engaged. For careful adjustment of the crankshaft position there, is a hand wheel with which it is possible to perform manual turning.
There are precautions & protection using the turning gear. When starting the engine normally the turning gear must be disengaged. Imagine what would happen if the gear is engaged at the time of starting the engine! It would be a mechanical disaster.
There are sensors like proximity sensor used to safe operation of turning gear. If the turning gear is engaged, proximity sensor will sense it engine will be blocked to start. The two proximity sensor might be used. One sense the engagement and another the disengagement of turning gear. This is because , what if the turning gear is in middle of engagement and disengagement. Then the both sensor will sense no contact. So there should be two opposite signal – 1,0 or 0,1. not 1,1 or 0,0.