Last Answer : In a D.C. machine stray loss is the sum of iron loss and mechanical loss.
Show More
218 views
1 answer
asked
Mar 21, 2018
by
anonymous
Last Answer : Iron loss, copper loss and mechanical losses these are the losses in DC machine.
Show More
118 views
1 answer
asked
Sep 27, 2017
by
anonymous
Last Answer : Iron losses in a D.C. machine are independent of variations in load.
Show More
161 views
1 answer
asked
Mar 20, 2018
by
anonymous
In DC motor iron losses are occurred in?
Last Answer : In DC motor iron losses are occurred in the armature.
Show More
138 views
1 answer
asked
Mar 26, 2018
by
anonymous
Last Answer : Copper losses,iron losses,variable losses , constant losees
Show More
174 views
1 answer
Last Answer : In a D.C. generator, the iron losses mainly take place in armature rotor.
Show More
273 views
1 answer
asked
Mar 20, 2018
by
anonymous
Last Answer : The total losses in a well designed D.C. generator of 10 kW will be nearly 500 W.
Show More
138 views
1 answer
asked
Mar 20, 2018
by
anonymous
Why poles of dc machine are laminated?
Last Answer : Poles of DC machines are laminated to reduce the eddy current losses in the poles.
Show More
112 views
1 answer
asked
Apr 27, 2020
by
anonymous
Explain concept of back emf in DC machine. State how it governs armature current.
Last Answer : Back emf: When the armature of DC machine rotates under the influence of driving torque, the armature conductors move in the magnetic field and cut it and hence emf is induced in them. The ... flow of armature current i.e. it automatically changes the armature current to meet load requirements.
Show More
190 views
1 answer
asked
Jul 27, 2019
by
anonymous
A 200 V DC machine supplies 20 A at 200 V as a generator. The armature resistance is 0.2 Ohm. If the machine is now operated as a motor at same terminal voltage and current but with the flux increased by 10%, the ratio of motor speed to generator speed is
Last Answer : A 200 V DC machine supplies 20 A at 200 V as a generator. The armature resistance is 0.2 Ohm. If the machine is now operated as a motor at same terminal voltage and current but with the flux increased by 10%, the ratio of motor speed to generator speed is 0.87
Show More
127 views
1 answer
asked
May 8, 2018
by
anonymous
A 36 slot, 4 -pole, dc machine has a simplex lap winding with two conductors per slot. The back pitch and front pitch adopted could be respectively
Last Answer : A 36 slot, 4 -pole, dc machine has a simplex lap winding with two conductors per slot. The back pitch and front pitch adopted could be respectively 19,17
Show More
588 views
1 answer
asked
May 3, 2018
by
anonymous
The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors rotating at 600 rpm and with 1 Wb flux per pole is (1) 1000V (2) 100V (3) 600V (4) 10,000V
Last Answer : The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors rotating at 600 rpm and with 1 Wb flux per pole is 1000V
Show More
370 views
1 answer
asked
Apr 29, 2018
by
anonymous
Aluminium is not used as winding wire for the armature of a dc machine because (1) aluminium has low resistivity (2) a large winding space is taken by aluminium conductors and creates ... ) the thermal conductivity of aluminium is low (4) aluminium has low conductivity as compared to copper
Last Answer : Aluminium is not used as winding wire for the armature of a dc machine because (2) a large winding space is taken by aluminium conductors and creates jointing problems (3) the thermal conductivity of aluminium is low (4) aluminium has low conductivity as compared to copper
Show More
621 views
1 answer
asked
Apr 29, 2018
by
anonymous
In a dc machine, interpoles are used to (1) neutralize the effect of armature reaction in the interpolar region (2) generate more induced emf in the armature (3) avoid interference of the armature flux with the main -field flux (4) reduce the demagnetizing effect of armature reaction
Last Answer : In a dc machine, interpoles are used to neutralize the effect of armature reaction in the interpolar region
Show More
175 views
1 answer
asked
Apr 29, 2018
by
anonymous
The magnetic neutral plane shifts in a dc machine (A) in the direction of motion of motor (B) in the direction of motion of generator (C) due to increase in the field flux (D) cause reduction of flash over between commutator segments
Last Answer : The magnetic neutral plane shifts in a dc machine in the direction of motion of generator
Show More
162 views
1 answer
asked
Apr 28, 2018
by
anonymous
Brushes of DC machine are made up of ?
Last Answer : Brushes of DC machine are made up of carbon.
Show More
165 views
1 answer
asked
Mar 3, 2018
by
anonymous
What arc the errors occurring in measuring devices due to stray magnetic field and temp '? Explain how to compensate them.
Last Answer : 1. Error due to stray magnetic fields- Main magnetic field gets disturbed by external magnetic fields known as stray magnetic fields. 2. Compensation technique To avoid this error, ... resistance alloy having a negligible resistance temp coefficient in the ratio of 1:10 for pressure coil
Show More
170 views
1 answer
asked
Sep 6, 2018
by
anonymous
Last Answer : To avoid the effect of stray magnetic field in A.C. bridges we can use magnetic screening.
Show More
149 views
1 answer
asked
Mar 21, 2018
by
anonymous
Last Answer : To avoid formation of grooves in the commutator of a D.C. machine the brushes of opposite polarity should track each other.
Show More
3.0k views
1 answer
asked
Mar 21, 2018
by
anonymous
Last Answer : Open circuited armature coil of a D.C. machine is identified by the scarring of the commutator segment to which open circuited coil is connected and indicated by a spark completely around the commutator.
Show More
159 views
1 answer
asked
Mar 20, 2018
by
anonymous
.jpg)
Last Answer : In case of D.C. machine winding, number of commutator segments is equal to number of armature coils.
Show More
665 views
1 answer
asked
Mar 20, 2018
by
anonymous
84 views
0 answers
asked
Mar 20, 2018
by
anonymous
Last Answer : In a four-pole D.C. machine alternate poles are north and south.
Show More
81 views
1 answer
asked
Mar 20, 2018
by
anonymous
What are the types of power losses in inductor?
Last Answer : Copper losses, Eddy current loss, and hysteresis loss are the types of power losses in inductor.
Show More
118 views
1 answer
asked
Mar 8, 2018
by
anonymous
State the losses in secondary distribution system.
Last Answer : The losses in secondary distribution system: a) Technical losses: 1. Due to poor voltage 2. Due to unbalance load 3. Due poor quality of transformer & its components 4. Due to poor quality ... of induction type of energy meter. 3. Lack of administration. 4. Energy theft 5. Unmetered supply
Show More
122 views
1 answer
asked
May 3, 2020
by
anonymous
Explain the “mitigation of power theft” and “faulty meter replacement” for energy conservation techniques to reduce commercial losses.
Last Answer : Energy conservation techniques to reduce commercial losses: 1. Mitigation of Power Theft: Power theft being the most important issue which all of the service providing utilities ... agricultural sector. Prepaid meters may prove effective measures against unauthorized abstraction of energy.
Show More
121 views
1 answer
asked
Sep 22, 2018
by
anonymous
Explain following techniques related to energy conservation in transmission and distribution system. (i) By balancing phase currents (ii) Variable technical losses (I2R losses).
Last Answer : (i) Balancing Phase currents: Proper (healthy balanced) three phase loads always draw equal currents in all lines but single phase loads in the 3 phase 4 wire system or loads connected between two ... . 11) Minimize I2R losses. 12) Balance the load currents. 13) Regulate the system voltages.
Show More
195 views
1 answer
asked
Sep 22, 2018
by
anonymous
The friction losses in Real Transformers are : (A) 0% (B) 5% (C) 25% (D) 50%
Last Answer : A
Show More
3.3k views
2 answers
asked
May 8, 2018
by
anonymous
Which of the following can reduce the Eddy current losses? A) By making the core of a stack of plates electrically insulated from each other B) By making the core of solid block C) By increasing the applied voltage D) None of these
Last Answer : Which of the following can reduce the Eddy current losses? A) By making the core of a stack of plates electrically insulated from each other B) By making the core of solid block C) By increasing the applied voltage D) None of these
Show More
90 views
1 answer
asked
Apr 29, 2018
by
anonymous
Last Answer : In case of D.C. machines, mechanical losses are primary function of speed.
Show More
500 views
1 answer
asked
Mar 20, 2018
by
anonymous
.jpg)
Reduction in core losses and increase in permeability are obtained with transformer employing?
Last Answer : Reduction in core losses and increase in permeability are obtained with transformer employing core built-up of laminations of cold rolled grain oriented steel.
Show More
615 views
1 answer
asked
Mar 19, 2018
by
anonymous
.jpg)
Losses which occur in rotating electric machines and do not occur in transformers are?
Last Answer : Friction losses windage losses
Show More
208 views
2 answers
asked
Mar 19, 2018
by
anonymous
In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are?
Last Answer : In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are hysteresis and eddy current losses.
Show More
152 views
1 answer
asked
Mar 19, 2018
by
anonymous
Auto-transformer makes effective saving on copper and copper losses, when its transformation ratio is?
Last Answer : Auto-transformer makes effective saving on copper and copper losses, when its transformation ratio is approximately equal to 1.
Show More
160 views
1 answer
asked
Mar 19, 2018
by
anonymous
In a synchronous motor which losses varies with load?
Last Answer : In a synchronous motor, copper losses varies with load.
Show More
102 views
1 answer
asked
Mar 18, 2018
by
anonymous
Explain the electrical losses of magnetic materials used for the cores of inductors and transformer.
Show More
87 views
0 answers
asked
Mar 10, 2018
by
anonymous
What are the losses in a transmission line?
Show More
61 views
0 answers
asked
Mar 10, 2018
by
anonymous
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.
Show More
512 views
1 answer
asked
Mar 3, 2018
by
anonymous
Explain the on state losses in power BJT.
Last Answer : On state losses in power BJT: Transistor have four types of losses one is turn on state losses second is turn off state losses third is turn on switching losses and fourth is turn ... ON = VCE sat x IC With increasing collector current collector to emitter saturation voltage increases.
Show More
295 views
1 answer
asked
Sep 15, 2017
by
anonymous
The total power of an AM transmitter having a carrier power of 50 W and the percentage of modulation at 80% is A) 50 W B) 66 W C) 68 W D) 70 W
Last Answer : The total power of an AM transmitter having a carrier power of 50 W and the percentage of modulation at 80% is 66 W
Show More
325 views
1 answer
asked
Jun 18, 2018
by
anonymous
Which capacitors are suitable for DC filter circuits?
Last Answer : Electrolytic capacitors are suitable for DC filter circuits.
Show More
83 views
1 answer
asked
Mar 8, 2018
by
anonymous
Anyone care to join me in a quiet prayer for Jeret "Speedy" Peterson?
Last Answer : Not to sound cold, but it won’t help at this point.
Show More
0 views
1 answer
asked
Feb 27
by
anonymous
What is the function of the roll forming machine ?
Last Answer : It is much easier to make croissants and other dinner rolls with a roll forming machine, than it is to roll the croissants by hand. The primary function, therefore, is to take the mixed dough and to thin it, then fold it, to prepare the dough for baking.
Show More
1 view
1 answer
asked
Mar 2
by
anonymous
How to Repair a Washing Machine
Last Answer : How to Repair a Washing Machine One of the modern conveniences that most people cannot live without is their washing machine. Washing machines have become extremely commonplace in today's homes and while ... store for more information on fixing it, or whether it is worth replacing the entire unit.
Show More
11 views
1 answer
asked
May 14, 2021
by
anonymous
How to Repair a Sewing Machine
Last Answer : How to Repair a Sewing Machine As being one of the more heavy-duty appliances, sewing machines can provide many years of reliable use. Often they do need to be cleaned out due to the excess ... it does, you will have to increase the belt's tension by shifting the motor-mountain screws again.
Show More
10 views
1 answer
asked
May 14, 2021
by
anonymous
How to Thread a Sewing Machine
Last Answer : How to Thread a Sewing Machine So you finally found a pattern you want to sew. You've got your mom's trusty sewing machine out, but before you can start sewing away, you must first learn to thread the ... be an easy task. Soon, you'll be a whiz at threading a sewing machine and at sewing, too!
Show More
10 views
1 answer
asked
May 14, 2021
by
anonymous
How to Clean a Washing Machine
Last Answer : How to Clean a Washing Machine You need a washing machine to clean all your clothes and have them smelling clean, so have you ever thought about what it takes to keep the actual machine clean? ... of the washing machine dry. Repeat cleaning the front load washing machine at least once a month.
Show More
3 views
1 answer
asked
May 12, 2021
by
anonymous
10 Benefits of climber machine
Last Answer : 10 Benefits of climber machine The climber machine is tall, slim machine pinched away in the corner of the gym. Maybe you've seen someone on it apparently with his personal trainer in ferry. It's ... that will give more strength to the arms and legs and will increase the strength of the body too.
Show More
5 views
1 answer
asked
Apr 24, 2021
by
anonymous
.jpg)
How to choose a rowing machine and how to use it?
Last Answer : Many people know that it is easy to calculate rowing athletes against the background of other people by a special article. The beauty of their figure is formed during rowing sessions, which provide an ... times for 10 minutes with 10-minute breaks, this will be tantamount to one 30-minute lesson.
Show More
5 views
1 answer
asked
Mar 29, 2021
by
anonymous
Capsule coffee machine. What are the advantages?
Last Answer : Having a coffee maker in the house helps us to easily cheer up and brighten up the beginning of the upcoming day in the morning, especially if the weather is unpleasant. A cup of hot ... favor is the fact that the profile of this manufacturer is precisely capsule coffee makers and coffee capsules.
Show More
15 views
1 answer
asked
Mar 29, 2021
by
anonymous
