Advantage and disadvantage of repulsion type moving iron instrument?

Advantages

• The instruments are suitable for use in AC and DC circuits.
• The instruments are robust, owing to the simple construction of the moving parts.
• The stationary parts of the instruments are also simple.
• Instrument is low cost compared to moving coil instrument.
• Torque/weight ratio is high, thus less frictional error.

• Error due to variation in temperature.
• Error due to friction is quite small as torque-weight ratio is high in moving coil instruments.
• Stray fields cause relatively low values of magnetizing force produced by the coil. Efficient magnetic screening is essential to reduce this effect.
• Error due to variation of frequency causes change of reactance of the coil and also changes the eddy currents induced in neighbouring metal.
• Deflecting torque is not exactly proportional to the square of the current due to non-linear characteristics of iron material.