Several electrical machines and panels are installed on board so that the ship can safely and efficiently navigate from port to port. The electrical machinery and the system require scheduled maintenance and controls to avoid any type of damage during navigation.
Different instruments are used on board to measure various electrical parameters to analyze and maintain these machines in good working condition. A permanent magnet mobile coil (PMMC) is one of these instruments that is popularly used on board and has several applications. The other popular nomenclature of this instrument is D'alvanometer and galvanometer.
Permanent magnet mobile coil: working principle
When a current carrying conductor is placed in a magnetic field, it experiences a force and tends to move in the direction according to Fleming's left hand rule.
Fleming left hand rule:
If the first and second fingers and the thumb of the left hand are held so that they are at right angles to each other, then the thumb shows the direction of the force on the conductor, the first finger points in the direction of the magnetic and the second finger shows the direction of current in the cable.