Bissoy.com
Doctors Medicines MCQs Q&A

Below stated are some of the statements about the squirrel cage induction motor. You need to identify which of the following is incorrect. 1. Very poor speed control 2. Although they are energy-efficient white at full load, they need a lot of energy while being started. 3. They are susceptible to voltage variations. 4. The induction motor consumes more current when supply voltage is reduced. 5. They are explosion-proof as there are no brushes which eliminate the risks of sparking.

Below stated are some of the statements about the squirrel cage induction motor. You need to identify which of the following is incorrect. 1. Very poor speed control 2. Although they are energy-efficient white at full load, they need a lot of energy while being started. 3. They are susceptible to voltage variations. 4. The induction motor consumes more current when supply voltage is reduced. 5. They are explosion-proof as there are no brushes which eliminate the risks of sparking. Correct Answer None

Squirrel Cage Induction Motor:

  • A 3 phase squirrel cage induction motor is a type of three-phase induction motor which functions based on the principle of electromagnetism.
  • It is called a ‘squirrel cage’ motor because the rotor inside of it – known as a ‘squirrel cage rotor’ – looks like a squirrel cage.
  • This rotor is a cylinder of steel laminations, with highly conductive metal (typically aluminum or copper) embedded into its surface.

 

Advantages:

  • They are low cost
  • Require less maintenance as there are no slip rings or brushes
  • Good speed regulation as they are able to maintain a constant speed
  • High efficiency in converting electrical energy to mechanical energy while running
  • Have better heat regulation
  • Small and lightweight
  • Explosion-proof as there are no brushes which eliminates the risks of sparking.

 

Disadvantages:

  • Very poor speed control.
  • Although they are energy efficient while running at full load current, they consume a lot of energy on start-up.
  • They are more sensitive to fluctuations in the supply voltage.
  • When the supply voltage is reduced, the induction motor draws more current.
  • During voltage surges, an increase in voltage saturates the magnetic components of the squirrel cage induction motor
  • They have high starting current and poor starting torque (the starting current can be 5-9 times the full load current, the starting torque can be 1.5-2 times the full load torque)

Related Questions

In the following question, sentences of a paragraph have been jumbled and labelled as A, B, C and D. You are required to rearrange the jumbled sentences of the paragraph and mark your response accordingly by selecting the correct option. A: An induction motor can, therefore, be made without electrical connections to the rotor. B: Three-phase squirrel-cage induction motors are widely used as industrial drives because they are self-starting, reliable and economical. C: An induction motor's rotor can be either wound type or squirrel-cage type. D: An induction motor or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding.
(I) Even at no load a large 3-phase squirrel- cage induction motor is started at reduced voltage than rated. (II) If a large 3–phase squirrel-cage induction motor with no load is started at full voltage, it will be damaged.
The cages of five animals, Lion, Tiger, Elephant, Giraffe and Zebra were kept in a line one after the other, not necessarily in the same order. Lion’s cage is not kept at the last and giraffe’s cage is not kept at the first. Tiger’s cage was kept at the centre of the line. Zebra’s cage was kept after Lion’s but before Tiger’s cage. There was one cage kept between Tiger’s and Giraffe’s cage. Whose cage is kept at the last in the line?
The question given below consists of a statement, followed by three arguments numbered I, II and III. You have to decide which of the arguments is/are ‘strong’ arguments and which is/are ‘weak’ arguments and accordingly choose your answer from the alternatives given below each question. Statement: A shortage of bank branches and ATMs across India’s hinterland is holding back Prime Minister Narendra Modi’s financial inclusion efforts and risks angering rural voters ahead of elections next year. After taking office in 2014, Modi set an ambitious target to open a bank account for every household to ensure welfare funds flow directly to India’s poor, while improving access to credit and insurance programs. He pushed policies that helped bring 310 million people into the formal banking system in just four years, according to the World Bank. Based on the arguments stated below and he information stated above, which of the following arguments state the reason for the problem, ‘But many of India’s villages still lack bank branches or ATMs to help service new customers, while the pace of building new financial infrastructure has actually slowed’.  Arguments: I. Because Modi’s government effectively forced poor citizens into the banking system by linking some welfare benefits to bank accounts, villagers have ended up stuck in long queues and struggling with ATMs that often run out of cash or break down.  II. With an election due next year, the mismatch between the government’s policies and the rural banking system is generating frustration among a key slice of India’s electorate. III. The banking system struggled to keep up, while some gains proved temporary. Nearly half of Indian bank accounts were inactive in 2017, meaning they weren’t used at all in the previous 12 months
Below stated are some of the statements about the Alternating current. You need to identify which of the following is incorrect, 1. DC power is far more powerful than AC power. The efficiency and power to size characteristics of DC motors and apparatuses are increased. Lighting by DC (LED) is 75% more efficient than lighting from incandescence. 2. A comparatively high voltage alternating current may be generated and easily raised and dropped by the static equipment known as the transformer, which makes electrical energy transmission and distribution economical, 3. Initial costs and maintenance of the AC motor are less expensive since it has no switch and is less powerful than the DC motor for constant working speed, hence it is desired to create power as alternating current. 4. The great efficiency of transmission in ac makes electric power generation cost-effective, Produced in huge quantities in one station and distributed throughout a vast area.
Read the passage carefully and choose the best answer to each question out of the four alternatives and click the button corresponding to it.
Modern civilization is completely dependent on energy, which has therefore to be abundant and also economical. About 85% of the world's energy is supplied by oil, coal and natural gas while nuclear, hydro, wind and solar power and biomass supply the rest. Coal, nuclear and hydro are used primarily to generate electricity while natural gas is widely used for heating. Biomass is used both for heating and cooking. The wind and solar power is the future's hope as they are sustainable energy sources. Oil powers almost all machines that move and that makes oil uniquely versatile. Oil powered airplanes carry 500 people across the widest oceans at nearly the speed of sound. Oil powered machines produce and transport food. Oil powered machines are ubiquitous. Clearly, we live in the age of oil but it is drawing to a close. According to data available if oil production remains constant until it's gone, there is enough to last 42 years. Oil wells will produce less as they become depleted, which will make it impossible to keep production constant. Similarly natural gas and coal will last another 61 years and 133 years respectively. Naturally, as they become scarce, they become expensive, leading to a worldwide energy crisis. If we are to survive on this planet, we have to make a transition to sustainable energy sources. The transition may be willy-nilly or planned - the choice is ours. The dawning era of limited and expensive energy will be very difficult for everyone on earth but will be even more difficult if it is not anticipated. It is of utmost importance that the public and policymakers understand the global energy crisis and act in tandem to ensure that the species 'homo sapiens' does not become extinct. Biomass is an energy source used in
Read the passage carefully and choose the best answer to each question out of the four alternatives and click the button corresponding to it.
Modern civilisation is completely dependent on energy, which has therefore to be abundant and also economical. About 85% of the world's energy is supplied by oil, coal and natural gas while nuclear, hydro, wind and solar power and biomass supply the rest. Coal, nuclear and hydro are used primarily to generate electricity while natural gas is widely used for heating. Biomass is used both for heating and cooking. The wind and solar power is the future's hope as they are sustainable energy sources. Oil powers almost all machines that move and that makes oil uniquely versatile. Oil powered airplanes carry 500 people across the widest oceans at nearly the speed of sound. Oil powered machines produce and transport food. Oil powered machines are ubiquitous. Clearly, we live in the age of oil but it is drawing to a close. According to data available if oil production remains constant until it's gone, there is enough to last 42 years. Oil wells will produce less as they become depleted, which will make it impossible to keep production constant. Similarly natural gas and coal will last another 61 years and 133 years respectively. Naturally, as they become scarce, they become expensive, leading to a worldwide energy crisis. If we are to survive on this planet, we have to make a transition to sustainable energy sources. The transition may be willy-nilly or planned - the choice is ours. The dawning era of limited and expensive energy will be very difficult for everyone on earth but will be even more difficult if it is not anticipated. It is of utmost importance that the public and policymakers understand the global energy crisis and act in tandem to ensure that the species 'homo sapiens' does not become extinct. The energy sources of the future are
A passage is given with five questions following it. Read the passage carefully and select the best answer to each question out of the given fouralternatives. Just as space permeates everything in the universe, love permeates every part, every aspect of creation. If there is one answer to the question, “How and why doesthis world exist?” the answer, in one word, is Love. Rather, the answer is Pure Love, since the word love has lost its meaning. Your very existence is an expression of pure unconditional love of the Source (you may call it Consciousness, Creator, God, Divine Self). This is the truth of your being.True love transcends both love and hatred. It is unconditional, unquestioning, boundless, unchanging love. It is overflowing love of the Source for the Source throughall of creation. True love is way beyond the personalized love that two or more individuals assert on one another. Personalized love, though apparently selfless, is rooted in desiresand conditional satisfaction. We have been brought up in a society that judges love based on conditions. We have been made to believe that we can receive love only when we fit into peoplesexpectations. If we are not good enough, we will be deprived of love. These beliefs have influenced the collective psyche of families, groups, communities, and societies since generations to such an extent that love has been reduced tofear of denial. We need to shift from the paradigm of false conditional love to the essence of pure unconditional love . The experience of true love comes with surrender of the false I, in letting go of the feeling of separateness. Without this sacrifice, it is not possible to attain divinelove. When this separate I is discarded, you embrace everything in oneness and catch a glimpse of pure love. True love can be experienced only through giving, not by demanding. People who exist in your life are not here to love you. They are here to remind you that you arethe Source of Love. By knowing that you are the Source of love, you can love yourself, instead of waiting to receive love from the world. Ask yourself, “Why do I need an agent to love myself?” Waiting for the world to love you, is like hiring an agent to love yourself! It is time for you to honor yourself as the Source of love. You have undertaken this human journey to realize and express the boundless love that you truly are. According to the passage, which of the following statement is not TRUE?
A passage is given with five questions following it. Read the passage carefully and select the best answer to each question out of the given fouralternatives. Just as space permeates everything in the universe, love permeates every part, every aspect of creation. If there is one answer to the question, “How and why doesthis world exist?” the answer, in one word, is Love. Rather, the answer is Pure Love, since the word love has lost its meaning. Your very existence is an expression of pure unconditional love of the Source (you may call it Consciousness, Creator, God, Divine Self). This is the truth of your being.True love transcends both love and hatred. It is unconditional, unquestioning, boundless, unchanging love. It is overflowing love of the Source for the Source throughall of creation. True love is way beyond the personalized love that two or more individuals assert on one another. Personalized love, though apparently selfless, is rooted in desiresand conditional satisfaction. We have been brought up in a society that judges love based on conditions. We have been made to believe that we can receive love only when we fit into peoplesexpectations. If we are not good enough, we will be deprived of love. These beliefs have influenced the collective psyche of families, groups, communities, and societies since generations to such an extent that love has been reduced tofear of denial. We need to shift from the paradigm of false conditional love to the essence of pure unconditional love . The experience of true love comes with surrender of the false I, in letting go of the feeling of separateness. Without this sacrifice, it is not possible to attain divinelove. When this separate I is discarded, you embrace everything in oneness and catch a glimpse of pure love. True love can be experienced only through giving, not by demanding. People who exist in your life are not here to love you. They are here to remind you that you arethe Source of Love. By knowing that you are the Source of love, you can love yourself, instead of waiting to receive love from the world. Ask yourself, “Why do I need an agent to love myself?” Waiting for the world to love you, is like hiring an agent to love yourself! It is time for you to honor yourself as the Source of love. You have undertaken this human journey to realize and express the boundless love that you truly are. Which of the following statement(s) is/are TRUE about pure love?
For a constant load torque, the supply voltage of a squirrel cage induction motor is reduced by a factor of 0.5, its rotor current is modified by a factor is?