The Full Form of PMMC is‍ Permanent magnet moving coil.

Several electrical machines and panels are fitted onboard so that the ship can sail from one port to another, safely and efficiently. The electrical machinery and system require scheduled maintenance and checks to avoid any kind of breakdown during sailing.

Different instruments are used onboard for measuring several electrical parameters to analyze and keep these machines in proper running condition. A permanent magnet moving coil (PMMC) is one such instrument which is popularly used onboard and has several applications. The other popular nomenclature of this instrument is D’alvanometer and galvanometer.

When a current carrying conductor is placed in a magnetic field, it experiences a force and tends to move in the direction as per Fleming’s left-hand rule.

Fleming left-hand rule:

If the first and the second finger and the thumb of the left hand are held so that they are at right angle to each other, then the thumb shows the direction of the force on the conductor, the first finger points towards the direction of the magnetic field and the second finger shows the direction of the current in the wire.