(PMMC) Permanent magnet moving coil.
The PMMC instrument in most accurate type for DC measurement
The working principle of this instrument is same as aersoal type gol vonometer.
PRINCIPLE :-
When a movable coil is placed in the magnetic field it experience a torque and move .It represent the capability of a for to produced change in the rotation motion of body PMMC is only measure direct current D.C the PMMC can be used for direct current measurment only and induction type for A.C current measurment only remaining all meter can be used with either direct current of alternating current.
CONSTRUCTION :-
(1) Moving Coil :- The moving coil is wound or rectangular form is made up of jewel bearing. The coils moves freely in the field of permanent magnet.
(2) Magnetic System :- Magnet systems is a leader in convesational mobile interfaces providing superior user experience powered by chatbots and Al.
(3) Deamping :- Deamping torque is provided by movement of aluminium former moving magnetic field of the permanent magnet pointer and scale.
WORKING :- Due to instructin blue stationary magnetic field created by magnet and magnet produced by flowing the current in coil it deflecting torque is produced.
Td= BIL neuton
B = Flux density
I = Current
L = Length of coil
B = bridth of coil
A = Totel area of coil
Td= NBIL
↳ No.of terms
Deflecting torque → NBIL x b / NBIA
Force area of coil
Td ∝ I Td=K I
Controlling torque TC ∝ ∅
TC = C∅ → Angular deflection
TD = TC
C Ø = KI
∅ = k/C
∅ = I / ∅ ∝ I
I
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