Part 2. Moving Iron Instruments

Question 1

Write out the formulars for moving iron instruments θ and Md

Answer 1

θ=1/2I²/kdL/dT
Md=BILDN
Where Md=Mc at equilibrium

Question 2

Extension of range of moving coil instruments formulars

Answer 2

Rsc=(m-1)*Rm where m=V/Vm ( voltage multiplier connection series)
Rsh=Rm/(m-1) where m=I/Im (Current limiter or shunt(parallel connection)

Question 3

Dynamometer diagram

Answer 3

Question 4

Draw diagrams of shunt, multipliers and multirange ammeter and multirange voltmeter

Answer 4

DRAW it

Question 5

Construction and principle of operating a dynamometer

Answer 5

1.list the parts and CDS for construction
Principle of operating
1. Current low in fixed coil prod. Magnetic field
2. Flux density is proportional to the current B~I
3. Torque from the moving coil deflects the pointer on the scale