A 150 kW electric motor has an efficiency of 92 %, when it operates at full load. Calculate the losses in the...

A 150 kW electric motor has an efficiency of 92 %, when it operates at full load. Calculate the losses in the machine. 

(A) 92 kW (B) 150 kW (C) 163 kW (D) 13 kW 
by

1 Answer

Answer :

efficiency  -output /input * 100

150/0.92----------163(input)

losses-----(163--150)  ---------13kw.

by

Related questions

Maintain 850 OC for 1 hour (soaking time).  Cool the material to 60 OC in 4 hours. a) Calculate the efficiency of the furnace, if the specific heat of steel is 0.12 kcal/kgOC and fuel oil consumption per batch is 1400 litres.  GCV of fuel oil - 10200 kcal/kg,  Cost of fuel oil - Rs. 46,000/kL,  Sp. gr. of fuel oil - 0.92. b) Due to high cost of oil, the plant management decides to convert to a lower operating cost LPG fired furnace lined on the inside with ceramic fibre insulation and with an operating efficiency of 80%, for same requirement. The investment towards installation of the new furnace is Rs. 50 lakhs. Calculate the Return on Investment, if the plant operates two batches per day and 250 days in a year.  Cost of LPG - Rs. 75/kg,  GCV of LPG - 12500 kcal/kg.

Description : In a heat treatment shop, steel components are heat-treated in batches of 80 Tons. The  heat treatment cycle is as follows;  Increase temperature from 30 OC to 850 OC in 3 hours.  ... efficiency of 80%, for same requirement. The investment towards installation of  the new furnace is Rs. 50

Last Answer : Quantity of steel treated per batch - 80 Tons a. Efficiency of Furnace: Useful heat supplied to steel - 80000 x 0.12 x (850 - 30)   = 7872000 kcal/batch .1 mark Total heat ... = Rs. 64400/batch Efficiency of new LPG furnace - 80% Heat supplied in new LPG furnace - 7872000/0.8

Which of the following statements is correct concerning the motor performance curves and data table shown in the illustration? EL-0006 A. The motor RPM at full load is 1737 RPM. B. The motor draws 12.62 kw from the switchboard when operating at full load. C. If the motor was developing 10 HP its power factor would be 0.92. D. All of the above.

Description : Which of the following statements is correct concerning the motor performance curves and data table shown in the illustration? EL-0006 A. The motor RPM at full load is 1737 RPM. B. The motor draws 12.62 kw ... If the motor was developing 10 HP its power factor would be 0.92. D. All of the above.

Last Answer : Answer: D

A 40 kW engine has a mechanical efficiency of 80 %. If the frictional power is assumed to be constant with load, what is the approximate value of the mechanical efficiency at 50 % of the rated load? (a) 45% (b) 55 % (c) 65% (d) 75%

Description : A 40 kW engine has a mechanical efficiency of 80 %. If the frictional power is assumed to be constant with load, what is the approximate value of the mechanical efficiency at 50 % of the rated load? (a) 45% (b) 55 % (c) 65% (d) 75%

Last Answer : Ans :c

The following heat engine produces power of 100,000 kW. The heat engine operates between 800 K and 300 K. It has a thermal efficiency equal to 50% of that of the Carnot engine for the same temperature. The rate at which heat is absorbed from the hot reservoir is (A) 100,000 kW (B) 160,000 kW (C) 200,000 kW (D) 320,000 kW

Description : The following heat engine produces power of 100,000 kW. The heat engine operates between 800 K and 300 K. It has a thermal efficiency equal to 50% of that of the Carnot engine for the same temperature. The rate at which heat is ... is (A) 100,000 kW (B) 160,000 kW (C) 200,000 kW (D) 320,000 kW

Last Answer : (D) 320,000 kW

A 3-phase 50HZ SCIM takes a power input of 30 KW at its full load speed of 1440 rpm. Total stator losses are 1 KW. The slip and rotor ohmic losses at full load are a) 0.02, 600 W b) 0.04, 580 W c) 0.04, 1160 W d) 0.04, 1200 W

Description : A 3-phase 50HZ SCIM takes a power input of 30 KW at its full load speed of 1440 rpm. Total stator losses are 1 KW. The slip and rotor ohmic losses at full load are a) 0.02, 600 W b) 0.04, 580 W c) 0.04, 1160 W d) 0.04, 1200 W

Last Answer : Ans: 0.04, 1160 W

What will be the efficiency when the transformer operates at unity power factor and 60% of full load

Description : What will be the efficiency when the transformer operates at unity power factor and 60% of full load 

Last Answer : What will be the efficiency when the transformer operates at unity power factor and 60% of full load 96.5%

A transformer operates 24 hours day at full -load. It's full -load efficiency is :

Description : A transformer operates 24 hours day at full -load. It's full -load efficiency is :  (A) equal all day efficiency (B) more than all -day efficiency (C) less than all -day efficiency (D) equal to maximum efficiency

Last Answer : A transformer operates 24 hours day at full -load. It's full -load efficiency is : equal all day efficiency 

A meter whose constant is 600 revolutions/kWh makes 5 revolutions in 20 seconds. Calculate the load in kW.

Description : A meter whose constant is 600 revolutions/kWh makes 5 revolutions in 20 seconds. Calculate the load in kW. (1) 0.5 kW (2) 1 kW (3) 1.5 kW (4) 2 kW  

Last Answer : 1.5 kW 

An electric heater draws 5 kW of power for continuous hot water generation in an industry. How much quantity of water in litres per min can be heated from 30oC to 85oC ignoring losses?. a) 1.3 b) 78.18 c) 275 d) none of the above

Description : An electric heater draws 5 kW of power for continuous hot water generation in an industry. How much quantity of water in litres per min can be heated from 30oC to 85oC ignoring losses?. a) 1.3 b) 78.18 c) 275 d) none of the above

Last Answer : a) 1.3

A transformer has maximum efficiency at 3/4 full load. The ratio of its iron losses and full load copper loss is : -

Description :  A transformer has maximum efficiency at 3/4 full load. The ratio of its iron losses and full load copper loss is : -  a) 16/9 b) 4 / 3 c) 3/4 d) 9 /16

Last Answer :  A transformer has maximum efficiency at 3/4 full load. The ratio of its iron losses and full load copper loss is : -  9 /16

A 50 KVA transformer has iron loss 2 kW on full load. Calculate its iron loss at 75% of full load.

Description : A 50 KVA transformer has iron loss 2 kW on full load. Calculate its iron loss at 75% of full load.

Last Answer : Iron loss is dependent on voltage and independent of load. Hence iron loss at 75% of Load = Iron loss at full load = 2 kW

A 10,000-watt motor operates an elevator weighing 5000 newtons. Assuming no frictional losses, how high is the elevator raised in 10 seconds. Is it raised: w) 2 meters x) 20 meters y) 50 meters z) 100 meters

Description : A 10,000-watt motor operates an elevator weighing 5000 newtons. Assuming no frictional losses, how high is the elevator raised in 10 seconds. Is it raised: w) 2 meters x) 20 meters y) 50 meters z) 100 meters

Last Answer : ANSWER: X -- 20 METERS

A three phase induction motor is drawing 16 Ampere at 440 Volts. If the operating power factor of the motor is 0.90 and the motor efficiency is 92%, then the mechanical shaft power output of the motor is a) 12.04 kW b) 10.09 kW c) 10.97 kW d) None of the above

Description : A three phase induction motor is drawing 16 Ampere at 440 Volts. If the operating power factor of the motor is 0.90 and the motor efficiency is 92%, then the mechanical shaft power output of the motor is a) 12.04 kW b) 10.09 kW c) 10.97 kW d) None of the above

Last Answer : b) 10.09 kW

A 400 V, 15 kW, 4-pole, 50 Hz, Y-connected induction motor has full load slip of 4%. The output torque of the

Description : A 400 V, 15 kW, 4-pole, 50 Hz, Y-connected induction motor has full load slip of 4%. The output torque of the machine at full load is  (A) 1.66 Nm (B) 95.50 Nm (C) 99.47 Nm (D) 624.73 Nm

Last Answer : A 400 V, 15 kW, 4-pole, 50 Hz, Y-connected induction motor has full load slip of 4%. The output torque of the machine at full load is 99.47 Nm

In a 2 kW, 200 V, 1000 rpm. DC series motor the torque at full load was found to be 0.3 N -m. The torque at

Description : In a 2 kW, 200 V, 1000 rpm. DC series motor the torque at full load was found to be 0.3 N -m. The torque at half full load in N -m is :

Last Answer : In a 2 kW, 200 V, 1000 rpm. DC series motor the torque at full load was found to be 0.3 N -m. The torque at half full load in N -m is : 0.075

A three-phase alternator operates at 450 volts with a power factor of 0.8. If the ammeter indicates 250 amperes, what should be the KW meter reading? A. 90.00 KW B. 127.27 KW C. 155.70 KW D. 194.85 KW

Description : A three-phase alternator operates at 450 volts with a power factor of 0.8. If the ammeter indicates 250 amperes, what should be the KW meter reading? A. 90.00 KW B. 127.27 KW C. 155.70 KW D. 194.85 KW

Last Answer : Answer: C

Which of the listed motors will operate at the highest RPM, assuming that each operates at the same frequency? A. A four-pole synchronous motor under normal load. B. A four-pole induction motor under no load. C. A six-pole synchronous motor under normal load. D. A six-pole induction motor under full load.

Description : Which of the listed motors will operate at the highest RPM, assuming that each operates at the same frequency? A. A four-pole synchronous motor under normal load. B. A four-pole induction motor under ... A six-pole synchronous motor under normal load. D. A six-pole induction motor under full load.

Last Answer : Answer: A

One 200 KVA transformer has an iron loss of 1 KW and full load Cu loss of 2 KW. Its load KVA corresponding...

Description : One 200 KVA transformer has an iron loss of 1 KW and full load Cu loss of 2 KW. Its load KVA corresponding to maximum efficiency is:  (A) 100 KVA (B) 141.4 KVA (C) 50 KVA (D) 200 KVA 

Last Answer : 100

The total losses in a well designed D.C. generator of 10 kW will be nearly?

Last Answer : The total losses in a well designed D.C. generator of 10 kW will be nearly 500 W.

A satellite transmitter operates at 4GHz with an antenna gain of 4dBi. The receiver 40000 km away has an antenna gain of 50 dBi. If the transmitter has a power of 8 W, find (ignoring feedline losses and mismatch) the EIRP in dBW. A. 50 B. 69 C. 49 D. 30

Description : A satellite transmitter operates at 4GHz with an antenna gain of 4dBi. The receiver 40000 km away has an antenna gain of 50 dBi. If the transmitter has a power of 8 W, find (ignoring feedline losses and mismatch) the EIRP in dBW. A. 50 B. 69 C. 49 D. 30

Last Answer : C. 49

A 220/440 V, 50 Hz, 5 KVA, single phase transformer operates on 220V, 40Hz supply with secondary winding open circuited. Then (A) Both eddy current and hysteresis losses decreases. (B) Both eddy current and hysteresis losses increases. (C) Eddy current loss remains the same but hysteresis loss increases. (D) Eddy current loss increases but hysteresis loss remains the same.

Description : A 220/440 V, 50 Hz, 5 KVA, single phase transformer operates on 220V, 40Hz supply with secondary winding open circuited. Then (A) Both eddy current and hysteresis losses decreases. (B) Both ... same but hysteresis loss increases. (D) Eddy current loss increases but hysteresis loss remains the same.

Last Answer : (A) Both eddy current and hysteresis losses decreases.

A partially saturated sample of soil has a unit weight of 2.0 g/cm3 and specific gravity of soil particles is 2.6. If the moisture content in the soil is 20%, the degree of saturation is (A) 20 % (B) 77 % (C) 92 % (D) None of these

Description : A partially saturated sample of soil has a unit weight of 2.0 g/cm3 and specific gravity of soil particles is 2.6. If the moisture content in the soil is 20%, the degree of saturation is (A) 20 % (B) 77 % (C) 92 % (D) None of these

Last Answer : Answer: Option C

A soil sample of mass specific gravity 1.92 has moisture content 30%. If the specific gravity of solids is 2.75, the degree of saturation, is (A) 95.4 % (B) 95.5 % (C) 95.6 % (D) 95.7 %

Description : A soil sample of mass specific gravity 1.92 has moisture content 30%. If the specific gravity of solids is 2.75, the degree of saturation, is (A) 95.4 % (B) 95.5 % (C) 95.6 % (D) 95.7 %

Last Answer : Option D

Account Receivables lag impacts sales. At no credit terms, the appeal falls to about ______ %, at 30 days, appeal is _____ %, at 60 days, appeal is ______%. a. 98.5, 92, 65 b. 65, 92, 98.5 c. 70, 85, 99 d. none of the above, there is no impact

Description : Account Receivables lag impacts sales. At no credit terms, the appeal falls to about ______ %, at 30 days, appeal is _____ %, at 60 days, appeal is ______%. a. 98.5, 92, 65 b. 65, 92, 98.5 c. 70, 85, 99 d. none of the above, there is no impact

Last Answer : b. 65, 92, 98.5

Punjab has farm power ok intensity of ...... a. 200 W/ hector. c) 150 kW/hector b. 3.5 kW/hector d) 3.5 W/hector

Description : Punjab has farm power ok intensity of ...... a. 200 W/ hector. c) 150 kW/hector b. 3.5 kW/hector d) 3.5 W/hector

Last Answer : 3.5 kW/hector

A shaft turns at 150 rpm under a torque of 1500 N-m. Power transmitted is (a) 15p kW (b) 10p kW (c) 7.5p kW (d) 5p kW (IES 1999) Hint: P = 2pNT/60

Description : A shaft turns at 150 rpm under a torque of 1500 N-m. Power transmitted is (a) 15p kW (b) 10p kW (c) 7.5p kW (d) 5p kW (IES 1999) Hint: P = 2pNT/60

Last Answer : (c) 7.5p kW

Weight per unit of drawbar power is generally ranges between a)50-120kg/kw b)120-150kg/kw c)150-250kg/kw d)250-300kg/kw

Description : Weight per unit of drawbar power is generally ranges between a)50-120kg/kw b)120-150kg/kw c)150-250kg/kw d)250-300kg/kw

Last Answer : a)50-120kg/kw

A single purchase crab has a handle 45 cm long and a drum of 25 cm diameter. The pinion has 30 teeth and spur has 150 teeth. The efficiency of the machine is 75%. If the maximum force that can be applied is 500 newtons, the maximum load that can be lifted will be a.9860 N b.6750 N c.20250 N d.1250 N e.13500 N

Description : A single purchase crab has a handle 45 cm long and a drum of 25 cm diameter. The pinion has 30 teeth and spur has 150 teeth. The efficiency of the machine is 75%. If the maximum force that can be applied is ... maximum load that can be lifted will be a.9860 N b.6750 N c.20250 N d.1250 N e.13500 N

Last Answer : b. 6750 N

The maximum demand of consumer is 2 kW and his daily energy consumption is 20 units. Its Load Factor is

Description : The maximum demand of consumer is 2 kW and his daily energy consumption is 20 units. Its Load Factor is (1) 10.15% (2) 41.6 % (3) 50 % (4) 60% 

Last Answer : Total maximum demand of energy in a day = 2kw*24= 48 units Consumer consumption is 20 units . Load factor = (number of units utilizing)/(total max. demand)      = 20/48 = 41.6%

By which of the following methods motor rating for variable load drives can be determined ? (a) Method of average losses (b) Equivalent current method (c) Equivalent torque method (d) Equivalent power method (e) All of the above.

Description : By which of the following methods motor rating for variable load drives can be determined ? (a) Method of average losses (b) Equivalent current method (c) Equivalent torque method (d) Equivalent power method (e) All of the above.

Last Answer : (e) All of the above.

In a synchronous motor which losses varies with load?

Description : In a synchronous motor which losses varies with load?

Last Answer : In a synchronous motor, copper losses varies with load.

In synchronous motor, does the winding losses vary with load?

Description : In synchronous motor, does the winding losses vary with load?

Last Answer : No, in the synchronous motor the winding losses do not vary with load.

A 3 phase 50 Hz induction motor has full load speed of 970 rpm. Calculate no of poles and slip frequency.

Description : A 3 phase 50 Hz induction motor has full load speed of 970 rpm. Calculate no of poles and slip frequency.

Last Answer : The number of poles in an induction motor can be calculated using the following formula: No. of poles = (120 * frequency) / speed In this case, the number of poles would be calculated as follows: No. of poles = ( ... ) - 50 Hz = 8.08 Hz So the motor has 6 poles and a slip frequency of 8.08 Hz.

An engine produces 10 kW brake power while working with a brake thermal efficiency of 30%. If the calorific value of the fuel used is 40000 kJ/kg, then what is the fuel consumption? (a) 1.5 kg/hour (b) 3 kg/hour (c) 0.3 kg/hour (d) 1 kg/hour

Description : An engine produces 10 kW brake power while working with a brake thermal efficiency of 30%. If the calorific value of the fuel used is 40000 kJ/kg, then what is the fuel consumption? (a) 1.5 kg/hour (b) 3 kg/hour (c) 0.3 kg/hour (d) 1 kg/hour

Last Answer : Ans :b

The power generation potential in mini hydro power plant for a water flow of 3 m3 /sec with a head of 14 meters and with a system efficiency of 55% is a) 226.6 kW b) 76.4 kW c) 23.1 kW d) none of the above

Description : The power generation potential in mini hydro power plant for a water flow of 3 m3 /sec with a head of 14 meters and with a system efficiency of 55% is a) 226.6 kW b) 76.4 kW c) 23.1 kW d) none of the above

Last Answer : a) 226.6 kW

A circuit breaker for a 300 KW alternator is rated at 470 amperes of full continuous load. The amount of overcurrent allowed is 125%. Which of the following conditions will trip the breaker? A. Sustained current flow of 470 amperes. B. Sustained current flow of 500 amperes for 10 minutes. C. Momentary starting load of 550 amperes. D. Sustained current flow of 590 amperes.

Description : A circuit breaker for a 300 KW alternator is rated at 470 amperes of full continuous load. The amount of overcurrent allowed is 125%. Which of the following conditions will trip the breaker? A. ... 10 minutes. C. Momentary starting load of 550 amperes. D. Sustained current flow of 590 amperes.

Last Answer : Answer: D

The nucleus `._(92)^(235)U` decays according to `._(92)^(238)U rarr ._(92)^(234)Th + ._(2)^(4)He`. Calculate the kinetic energy of the emitted `alpha`

Description : The nucleus `._(92)^(235)U` decays according to `._(92)^(238)U rarr ._(92)^(234)Th + ._(2)^(4)He`. Calculate the kinetic energy of the emitted `alpha`

Last Answer : The nucleus `._(92)^(235)U` decays according to `._(92)^(238)U rarr ._(92)^(234)Th + ._(2)^(4)He`. ... kg " " ._(2)^(4)He = 6.64807 xx 10^(-27)`

Calculate the energy released by fission of 1 g of `._(92)^(235)U`, assuming that an energy of 200 MeV is released by fission of each atom of `.^(235)

Description : Calculate the energy released by fission of 1 g of `._(92)^(235)U`, assuming that an energy of 200 MeV is released by fission of each atom of `.^(235)

Last Answer : Calculate the energy released by fission of 1 g of `._(92)^(235)U`, assuming that an energy of 200 MeV is ... `= 6.023 xx 10^(26) kg mol^(-1)`)

A synchronous motor operates at 0.8 pf lagging. If the field current of the motor is continuously

Description : A synchronous motor operates at 0.8 pf lagging. If the field current of the motor is continuously increased  1. The power factor decreases upto a certain value of field current and thereafter it increases.  2. The armature current ... the correct answer is (a) 1, 2 (b) 3, 4 (c) 1, 3 (d) 2, 4

Last Answer : A synchronous motor operates at 0.8 pf lagging. If the field current of the motor is continuously increased  1. The power factor decreases upto a certain value of field current and thereafter it increases.  2. The armature current ... the correct answer is (a) 1, 2 (b) 3, 4 (c) 1, 3 (d) 2, 4

A 3-phase voltage source inverter operates in 180° conduction mode with a star connected resistive load. If input

Description : A 3-phase voltage source inverter operates in 180° conduction mode with a star connected resistive load. If input dc voltage is 100 V, then the peak to peak output line voltage is :

Last Answer : A 3-phase voltage source inverter operates in 180° conduction mode with a star connected resistive load. If input dc voltage is 100 V, then the peak to peak output line voltage is : 200 V

Water losses in water supply, is assumed as (A) 5 % (B) 7.5 % (C) 10 % (D) 15 %

Description : Water losses in water supply, is assumed as (A) 5 % (B) 7.5 % (C) 10 % (D) 15 %

Last Answer : (D) 15 %

Total mechanical losses ( frictional losses , pumping loss in intake and exhaust and power accessories) will amount to a.10-20 % ihp b.2-10 % ihp c.20-30 % ihp d.30 -50 % ihp

Description : Total mechanical losses ( frictional losses , pumping loss in intake and exhaust and power accessories) will amount to a.10-20 % ihp b.2-10 % ihp c.20-30 % ihp d.30 -50 % ihp

Last Answer : a.10-20 % ihp

In a furnace employing forced draught as compared to induced draught, (A) Air is sucked in, so air leaks are more and hence the furnace efficiency is reduced (B) The fan operates hot and hence blades are liable to corrosion and erosion (C) Positive pressure exists in the furnace (D) None of these

Description : In a furnace employing forced draught as compared to induced draught, (A) Air is sucked in, so air leaks are more and hence the furnace efficiency is reduced (B) The fan operates hot and hence blades are liable to corrosion and erosion (C) Positive pressure exists in the furnace (D) None of these

Last Answer : (C) Positive pressure exists in the furnace

Pick out the correct statement. (A) Compression ratio of an Otto engine is comparatively higher than a diesel engine (B) Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio (C) Otto engine efficiency decreases with the rise in compression ratio, due to decrease in work produced per quantity of heat (D) Diesel engine normally operates at lower compression ratio than an Otto engine for an equal output of work

Description : Pick out the correct statement. (A) Compression ratio of an Otto engine is comparatively higher than a diesel engine (B) Efficiency of an Otto engine is higher than that of a diesel ... Diesel engine normally operates at lower compression ratio than an Otto engine for an equal output of work

Last Answer : (B) Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio

List the various losses on a DC Motor.

Description : List the various losses on a DC Motor. 

Last Answer : The various losses on a DC Motor: 1) Winding losses (Copper losses): i) Armature winding losses ii) Shunt field losses iii) Series field losses 2) Core losses (iron losses): 3) Brush contact losses: 4) Windage and frictional (Mechanical losses):

If the lagging power factor of the load decreases, the line losses will

Description : If the lagging power factor of the load decreases, the line losses will (A) Decrease (B) Increase (C) Flrst decrease and then Increase (D) Remain same

Last Answer : If the lagging power factor of the load decreases, the line losses will Increase

A permanent magnet moving coil instrument gives full scale deflection of 25mA when a voltage of 75mV is applied across it. Calculate: (i) Resistance of shunt required for full scale deflection of 150 A. (ii) Series resistance for full scale deflection of 500 V.

Description : A permanent magnet moving coil instrument gives full scale deflection of 25mA when a voltage of 75mV is applied across it. Calculate: (i) Resistance of shunt required for full scale deflection of 150 A. (ii) Series resistance for full scale deflection of 500 V.

Last Answer : Answer :

Why are motor ratings given in KW and that of alternator and transformer given in KVA?

Description : Why are motor ratings given in KW and that of alternator and transformer given in KVA?

Last Answer : kW is the output mechanical power of a motor and is expressed in kW. kVA is the net (apparent) power input to the transformer. This input power is the output + losses. kW = kVA x system power factor

The rotor power output of a 3-phase induction motor is 15 KW and corresponding slip is 4%. The rotor copper loss will be (A) 600 W. (B) 625 W (C) 650 W (D) 700 W

Description : The rotor power output of a 3-phase induction motor is 15 KW and corresponding slip is 4%. The rotor copper loss will be (A) 600 W. (B) 625 W (C) 650 W (D) 700 W

Last Answer : Ans: B Rotor copper losses = rotor input- rotor output and output = (1-s) input ∴ Input = output/(1-s) = 15000 /1-0.04 = 15625 ∴ loss = 15625 -1500 = 625 watt

A 3-phase, 400 votts, 50 Hz, 100 KW, 4 pole squirrel cage induction motor with a rated slip of 2% will have a rotor speed of (A) 1500 rpm (B) 1470 rpm (C) 1530 rpm (D) 1570 rpm

Description : A 3-phase, 400 votts, 50 Hz, 100 KW, 4 pole squirrel cage induction motor with a rated slip of 2% will have a rotor speed of (A) 1500 rpm (B) 1470 rpm (C) 1530 rpm (D) 1570 rpm

Last Answer : Ans: B N = NS (1-S) and NS =120 f / p =120 x 50 /4 = 1500 rpm ∴N= 1500 (1-0.02) =1470 rpm