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Assignment of EEMI (3rd sem Electrical) (1) (2) (3) (4) (5) (6) Explain construction & working of PMMC Instrument. Give classification of analog instruments. Derive expression for Deflecting torque of a single phase induction type meter. Discuss various effects which can be used for deflecting system of an instrument. What is an ‘ammeter shunt’? Explain how it is used in case of ammeters. The inductance of a moving iron ammeter is given by the expression : = 10 + 5 − 2 Where θ is the angular deflection in radians from zero position. If the deflection for a current of 5A is 30 degree, find the angular deflection in radians for a current of 10 A. Also determine the spring constant. (7) A 1mA meter d’Arsonval movement with an internal resistance of 100Ω is to be converted into 0-100 mA ammeter. Calculate the shunt resistance required. What will be the range of ammeter if shunt resistance is doubled? (8) Explain the working principle and construction of the dynamometer type measuring instrument with clean diagram. Also explain the deflecting and controlling torque & advantages and disadvantages of dynamometer type instrument. (9) Which are the types of moving iron Ammeter and voltmeters. Explain the principle, construction and working of both moving iron type instruments with diagram. And also give the advantages and disadvantages. (10) The moving coil meter has 60 turns width of 2 cm and depth of 3 cm. It hangs in magnetic field of 50 milli wb/m2 . Find the turning movement of coil when it is carrying current of 1 mA. (11) Derive = + 1 for extension of Ammeter and Voltmeter ranges using shunt and multiplier. (12) 3-mA meter movement with internal resistance of 100 ohm is to be converted into 0-150 mA ammeter. Calculate the value of shunt resistor. (13) A shunt resistance of 300 ohm is used with galvanometer having internal resistance of 1500 ohm. Calculate the multiplying power of shunt. If it is required to make the multiplying power equal to 40: then calculated value of shunt resistor. (14) Explain following terms: (a) Multi-range Ammeter (b) Universal shunt (c) precaution taken while using an Ammeter. (15) (a) Explain Basic DC voltmeter with diagram and also derive the equation for series resistance (multiplier) (16) (17) (18) (19) (20) (21) (b) A basic d’arsonval movement is having the full scale deflection of 50 micro amperes. An internal resistance of meter is 200 ohm. Calculate the value of multiplier to obtain the voltage range of 0 to 20 volts. (c) A dc voltmeter having voltage range of 0 to 10 volts. An internal resistance of meter is 400 ohm. Calculate the current required to cause the full scale deflection: if 200 kilo ohm multiplier is used. what is seeback effect? Explain the thermocouple type instruments with diagram. Design a multi-range DC milli-ammeter using basic movement having an internal resistance of 100 ohm and full scale deflection current of 1 mA. The required current range are 0-20 mA, 0-100 mA and 0-2 mA. A 1 mA meter d’arsonval movement with an internal resistance of 100 ohm is to be converted into 0-100 mA. Calculate the shunt resistance required. What will be the range of ammeter if shunt resistance is double. (a)sensitivity of voltmeter. (b)A dc voltmeter uses 150 micro ampere meter movement & having an internal resistance of 200 ohm. Calculate the value of multiplier on the 50 V range. A moving coil instrument gives maximum deflection for 15 mA. It has a resistance of 5 ohm. Calculate the value of shunt resistance required to make it read up to 10 Amps. Find the multiplying power of shunt of 200 ohm resistance used with galvanometer of 1000 ohm resistance. Determine the value of shunts to obtain multiplying power of 5, 10, 50.