Can you help by answering this question?

The colour having shortest wavelength in the following is

9 views
in Electrical Engineering by

Your answer

Thanks for your contribution. Feel free to answer this question. Please avoid short answer. Your answer is most welcome. Be genuine.

Upload image or document:

Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:
Are you a robot ? (Y = Yes / N = No)
To avoid this verification in future, please log in or register.

1 Answer

0 votes
by

The purpose of skewing of rotor slots in induction motor is to reduce the locking tendency of rotor.

Related questions

2 answers 89 views

In the Squirrel cage induction motors, the rotor slots are usually a slight skew to reduce (A) Windage losses (B) Eddy currents (C) Accumulation of dirt and dust (D) Magnetic hum

asked May 12, 2018 in Induction Machine by Shimroz123
0 answers 20 views

The stator of a 3 phase, 10 pole induction motor possesses 120 slots. If a lap winding is used, calculate the coil pitch, if the coil width extends from slot 1 to slot 11.  (A) 72.12% (B) 83.30% (C) 12% (D) 42% 

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
1 answer 21 views

A centre zero ammeters connected in the rotor circuit of a 6-pole 50 Hz induction motor makes 30 oscillations in one minute. The rotor speed is

asked Apr 1, 2018 in Electrical Engineering by Shimroz123
1 answer 10 views

Skewing of rotor bars eliminate the: (1) Effect of space harmonics (2) Entire effect of crawling (3) Magnetic noise (4) Vibration due to unequal force developed on rotor

asked May 22, 2018 in Electrical Machine by Shimroz123
0 answers 19 views

The power input to the rotor of a 400V, 50 Hz 6 pole three phase induction motor is 20kW. The slip is 3%. The frequency of rotor currents is: (A) 1 Hz (B) 1.5 Hz (C) 2 Hz (D) 1 2 Hz

asked Apr 14, 2018 in Electrical Engineering by Shimroz123
0 answers 21 views

If the supply frequency of a 3-phase induction motor is ‘f’, then frequency of rotor emf at motor slip ‘s’ will be   (a) sf (b) (1 – s)f (c) f/s (d) None of these 

asked Apr 10, 2018 in Electrical Engineering by Shimroz123
0 answers 51 views

If the stator winding of a three-phase induction motor is delta connected, the rotor winding   (a) should be delta connected (b) should be star connected (c) should not be delta connected (d) may be delta or star connected 

asked Apr 10, 2018 in Electrical Engineering by Shimroz123
0 answers 22 views

Calculate the approximate locked rotor current of a 3 phase induction motor having a rating of 500 Hp, 2300 V.  (A) 130 A (B) 39 A (C) 390 A (D) 780 A 

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
0 answers 41 views

A 0.5 Hp, 6 pole wound rotor induction motor is excited by a 3 phase 60 Hz source. Calculate the frequency of the rotor current at standstill.  (A) 50 Hz (B) 30 Hz (C) 60 Hz (D) 120 Hz 

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
1 answer 34 views

The ratio of rotor output to rotor input in an induction motor is 0.96. The slip of the motor is (a) 0.04% (b) 4% (c) 6% (d) 12%

asked May 25, 2018 in Induction Machine by Shimroz123
1 answer 39 views

The frequency (fr) of the rotor current in an induction motor is given by the expression (s = slip, f = supply frequency)

asked May 15, 2018 in Induction Machine by Shimroz123
0 answers 7 views

In an induction motor high rotor resistance is required for (a) Power factor and low starting current (b) high power factor and high starting current (c) high power factor and low starting current (d) low slip and high efficiency

asked Apr 14, 2018 in Electrical Engineering by Shimroz123
1 answer 322 views

in a three-phase induction motor, the rotor field runs at the following speed with respect to the stator structure: 

asked May 22, 2018 in Induction Machine by Shimroz123
1 answer 16 views

In a single phase induction motor driving a fan load, the reason for having a high resistance rotor is to achieve (A) low starting torque (B) quick acceleration (C) high efficiency (D) reduced size

asked May 17, 2018 in Induction Machine by Shimroz123
1 answer 80 views

The locked rotor current in a 3-phase, star connected 15 , kW 4 , pole 230 V , 50 Hz induction motor at rated conditions is 50 A. Neglecting losses and magnetizing current, the approximate locked rotor line current drawn when the motor is connected to a 236 , V 57 Hz supply is  (A) 58.5 A (B) 45.0 A (C) 42.7 A (D) 55.6 A

asked May 17, 2018 in Electrical Machine by Shimroz123
1 answer 23 views

In a single-phase induction motor when the rotor is stationary and voltage is applied to the stator, then (A) the flux is constant (B) the flux first decreases and then increases in the same direction (C) the flux increases and decreases in the opposite direction with the same magnitude (D) current flows through the rotor

asked Apr 28, 2018 in Electrical Machine by Shimroz123
0 answers 24 views

The stator mmf and rotor mmf of a 3-phase induction motor (A) are equal (B) rotate with slip speed (C) are opposite but rotate with synchronous speed (D) rotate with the same rotor speed 

asked Jun 4, 2018 in Induction Machine by Shimroz123
1 answer 11 views

The rotor frequency for a 3-phase 6-pole, 1000 r.p.m. induction motor with a slip of 0.04 is (a) 2 Hz (b) 4 Hz (c) 6 Hz (d) 8 Hz  

asked May 25, 2018 in Induction Machine by Shimroz123
1 answer 60 views

A 6-pole, 50Hz, 3-φ induction motor is running at 950 r.p.m. and has Cu loss of 5kW. The rotor input is (a) 10 kW (b) 95 kW (c) 100 kW (d) 9.5 kW 

asked May 25, 2018 in Induction Machine by Shimroz123
1 answer 18 views

If a 3-phase, 400V, 50Hz, 4 pole induction motor is running at a slip of 5% then the relative speed of rotor field with respect to stator filed is:

asked May 22, 2018 in Induction Machine by Shimroz123
1 answer 40 views

The rotor impedance of a slip ring induction motor is (0.1 + j0.6)Ohm/ ph . The resistance/ph to be inserted into rotor to get maximum torque at starting should be

asked May 3, 2018 in Electrical machine design by Shimroz123
1 answer 32 views

A 3-phase, 4-pole, 50Hz induction motor runs at a speed of 1440 rpm. The rotating field produced by the rotor rotates at a speed of ________ rpm with respect to stator field. (A) 1500 (B) 0 (C) 1440 (D) 60

asked Apr 28, 2018 in Electrical Machine by Shimroz123
1 answer 27 views

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

asked Apr 11, 2018 in Computer Engineering by Shimroz123
0 answers 39 views

The rotor winding of a three phase wound rotor induction motor is equipped with a three phase diode rectifier connected to the slip rings and rectifier output is connected with chopper drive. Compared to conventional rotor resistance control scheme, the chopper controlled method  A) Enhances the motor rating B) Maintains the motor rating as such C) Derates the motor D) None of the above 

asked Apr 9, 2018 in Electrical Machine by Zeeshan
1 answer 15 views

A 3-phase induction motor under locked rotor condition and with stator supply, induces (A) small voltage at slip frequency (B) large voltage at rotor frequency (C) zero voltage at zero frequency (D) large voltage at slip frequency

asked Apr 25, 2018 in Electrical Engineering by Shimroz123
1 answer 34 views

An 8 pole wound rotor induction motor operating on 60 Hz supply is driven at 1800 r.p.m. by a prime mover in the opposite direction of revolving magnetic field. The frequency of the rotor current is (a) 30 Hz (b) 60 Hz (c) 120 Hz (d) 180 Hz 

asked May 25, 2018 in Induction Machine by Shimroz123
1 answer 29 views

An 8-pole, 50Hz, three-phase induction motor is running at 705rpm and has a rotor copper loss of 5kW. Its rotor input is (A) 5.06 kW (B) 0.3 kW (C) 100 kW (D) 83.33 kW

asked Apr 28, 2018 in Electrical Machine by Shimroz123
1 answer 24 views

Types of three phase induction motor rotor

asked Aug 9, 2017 in Electrical Machine by Zeeshan
1 answer 20 views

A three phase slip ring induction motor is fed from the rotor side with stator winding short circuited stator is: (1) Slip frequency (2) Supply frequency (3) Frequency corresponding to rotor speed (4) Zero

asked May 22, 2018 in Induction Machine by Shimroz123
1 answer 25 views

A 6 pole 3-phase wound-rotor induction machine is driven by another machine at 1800 rpm. The rotor of the induction machine is connected to a 50Hz system. If the mechanical rotation of the rotor is in the same direction as the rotor winding flux rotation, then frequency of the stator voltage will be

asked Apr 1, 2018 in Electrical Engineering by Shimroz123
1 answer 24 views

A permanent magnet stepper motor with 8 poles in stator and 6 poles in rotor will have a step angle of (a) 7.5° (b) 15° (c) 30° (d) 60°

asked Apr 25, 2018 in Electrical Engineering by Shimroz123
0 answers 34 views

 What does the shunt resistance component in the equivalent circuit of an Induction motor represent ? (A) Windage and frictional loss only (B) Core losses only (C) Core, windage and frictional loss (D) Copper losses in rotor

asked Apr 14, 2018 in Electrical Engineering by Shimroz123
0 answers 11 views

The reading of wattmeter in no load test of induction motor gives : (A) Friction and windage loss (B) Copper losses on no load in the stator (C) Core losses (D) Sum of all losses

asked Apr 14, 2018 in Electrical Engineering by Shimroz123
0 answers 12 views

In the equivalent circuit of a 3-phase induction motor, the mechanical load on the motor can be represented by a resistance of value (1) R2 (2) R2/S (3) R2(1-S)/S (4) (R2/S)+1 

asked Apr 11, 2018 in Electrical Engineering by Shimroz123
0 answers 45 views

Reduction in supply voltage by 10% will change the torque of an induction motor by   (a) 38% (b) 19% (c) 9.5% (d) No change 

asked Apr 10, 2018 in Electrical Engineering by Shimroz123
1 answer 58 views

Starting torque can be obtained in the case of a single phase induction motor with identical main and auxiliary windings by connecting:  (1) A capacitor across the mains (2) A capacitor in series with the machine (3) A capacitor is series with the auxiliary winding (4) Equal value capacitors in series with the main and the auxiliary windings

asked Apr 9, 2018 in Electrical Engineering by Shimroz123
0 answers 22 views

The diameter of the rotor shaft for an electric motor depends on which of the following (1) rpm only (2) hp only (3) hp and rpm (4) hp, rpm and Power factor 

asked Apr 11, 2018 in Electrical Engineering by Shimroz123
0 answers 624 views

The rotor of a stepper motor has no   (a) Winding (b) Commutator (c) Brushes (d) All of the above 

asked Apr 10, 2018 in Electrical Engineering by Shimroz123
1 answer 63 views

What type of excitation is given to the rotor winding of a synchronous motor?  (A) DC supply at 100 -250 V (B) AC supply at 400 V (C) Revolving field (D) Induction from stator currents 

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
0 answers 12 views

What is the pitch factor of a 4 pole alternator having 36 slots and a coil span of 1 to 8?  (A) 140° (B) 80° (C) 20° (D) 40°

asked Apr 5, 2018 in Electrical Engineering by Shimroz123
0 answers 14 views

A change of 5% in supply voltage to an induction motor will produce a change of approximately (a) 5% in the rotor torque (b) 7.5% in the rotor torque (c) 10% in the rotor torque (d) 25% in the rotor torque

asked Apr 25, 2018 in Electrical Engineering by Shimroz123
1 answer 20 views

 In a variable speed induction motor derive V/f kept constant over a wide range of its frequency variation. The motor operates in the following mode : -  a) Constant power mode b) Constant torque mode c) Constant slip mode d) Variable power and variable torque mode

asked Apr 11, 2018 in Electrical Engineering by Shimroz123
1 answer 20 views

In a single-phase induction motor, the operating direction is determined by the ________ A) Rotor B) Stator C) Starting circuit D) None of these

asked Apr 29, 2018 in Electrical Engineering by Shimroz123
1 answer 14 views

In the capacitor-start, capacitor-run single-phase induction motor (A) two capacitors are connected across the main winding (B) when the centrifugal switch opens, the permanent capacitor is left in the auxiliary winding circuit (C) when the centrifugal switch opens, the permanent capacitor is left in the main winding circuit (D) two capacitors are connected across the auxiliary winding.

asked Apr 25, 2018 in Electrical Engineering by Shimroz123

Welcome to electronics2electrical.com here you can ask questions related to electrical, electronics, mechanical, telecommunication, instrumentation, computer, mathematics, physics etc.
Be respectful to all the members. Do not copy and paste the answers from other websites which have copyright content. While asking question give full details about it.

Categories

Most popular tags

power motor dc circuit transformer voltage current used system phase resistance factor synchronous load ac energy induction electric generator series frequency between speed capacitor use electrical meter line difference control type mosfet transmission magnetic plant high single instrument bjt unit source advantages function diode and machine winding field define torque parallel amplifier supply shunt thyristor motors electricity arduino maximum time relay armature problem value on transformers types coil diagram state flow ratio material three formula starting direction theorem method emf operating efficiency digital wave microprocessor test instruments inductance loss measure operation connected signal low applications effect single-phase network temperature working constant losses different law wattmeter measuring compare controlled breaker drive device logic rc full switch flux wire resistivity disadvantages free of materials machines angle force converter conductor transistor gain open protection scr core measurement number bridge principle generators reactance circuits negative the friction iron loop short pole battery conservation steam resistors hysteresis computer using analog lines secondary station gate a rectifier inverter linear induced relays nuclear capacitance basic characteristics design direct work rotor electronics ammeter forces diesel damping rlc connection factors capacitors minimum insulation moving regulation running self systems air fault range main stability quality starter igbt eddy alternator ideal rl average 3-phase plants arc thermal error fuzzy biasing dielectric pressure balanced superposition errors copper rotation feedback impedance measured electronic electrons charge inductive transfer explain start off back curve over solar is three-phase tariff locomotive peak bias zener engineering commutator surge conductors rating universal potentiometer density permanent mechanical transducer capacity memory adc excitation two fuse pure harmonics application semiconductor inductor internal pmmc reaction welding resonance traction permeability breakers rms designed electromagnetic si generation brushes switching capacitive shaded rate 1 distribution resistor methods delta star oscillator reluctance simplification algebra 8085 boolean weston dynamometer insulating strength installation definition fuel heating earth units

8,503 questions

7,101 answers

134 comments

3,090 users

...