Differences Between Moving Coil (MC) And Moving Iron (MI) Instruments

Let us have a comparison between two major type of electrical measuring instruments they are moving coil (MC) and moving iron (MI) instruments.In this article all major differences between moving iron and  moving coil   instruments are discussed.When you go for viva or interview most often question on electrical measurements is what is the difference between mi and mc type instruments?.In this article you will get answer to all differences between MI & MC type instruments.

Differences Between Moving Coil (MC) And Moving Iron (MI) Instruments

M.C Instruments	M.I Instruments
1. MC type instruments are more accurate.	1. MI type are less accurate than MC type.
2. Manufacturing cost is high.	2. Cheap in cost.
3. Reading scale is uniformly distributed.	3. Non-uniform scale (scale cramped at beginning and finishing)
4. Very sensitive in construction & for input.	4. Robust in construction.
5. Low power consumption	5. Slightly high power consumption.
6. Eddy current damping is used.	6. Air friction damping is used.
7. Can be used only for D.C measurements.	7. Can be used for A.C as well as for D.C measurements.
8. Controlling torqure is provided by spring.	8. Controlling torque is provided by gravity or spring
9. Deflection proportional to current.( θ α I ).	9. Deflection proportional to square of current. ( θ α I² ).
10. Errors are set due to aging of control springs,permanent magnet (i.e. No Hysteresis loss)	10. Errors are set due to hysteresis and stray fields. (i.e. hysteresis loss takes place).

In this comparison between MC and MI Instruments we shared top points.

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