Bissoy.com
Doctors Medicines MCQs Q&A

The insulation resistance values of a Star connected squirrel cage induction motor with motor terminals U, V, W are UV = 0 MΩ; VW = 0 MΩ; UW = 0 MΩ; UE = 200 MΩ; VE = 200 MΩ; WE = 200 MΩ, WE = 200 MΩ. What is the health of the motor ?

The insulation resistance values of a Star connected squirrel cage induction motor with motor terminals U, V, W are UV = 0 MΩ; VW = 0 MΩ; UW = 0 MΩ; UE = 200 MΩ; VE = 200 MΩ; WE = 200 MΩ, WE = 200 MΩ. What is the health of the motor ? Correct Answer Motor insulation failed

Concept:

Following are standard result regarding insulation resistance:

  • The megger reading should be zero if the winding of the motor is having continuity.
  • The megger reading should be high or infinity (∞) if the winding of the motor is open.


Explanation:

To know the health of the motor, we should know the insulation resistance of the motor terminal.

In above question, the insulation resistance between winding are given as,

UV = 0 MΩ; VW = 0 MΩ; UW = 0 MΩ; UE = 200 MΩ; VE = 200 MΩ; WE = 200 MΩ, WE = 200 MΩ 

As we know that, 

  • The megger reading should be zero if the winding of the motor is having continuity.
  • The megger reading should be high or infinity (∞) if the winding of the motor is open.

 

The motor is healthy: All winding shows Zero resistance.

One of the windings got shorted to the body: If insulation resistance is measured between the frame of motor or winding then we can say that one winding got shorted to the body.

One of the windings got opened: If one of the winding is open then it shows high or infinity resistance.

We can say that some motor windings show high resistance and some are zero. Hence, Motor insulation failed.

Related Questions

Among the five stars, Star Z, Star Y, Star X, Star W, and Star V, Star W is brighter than Star Y and Star X. Star Z is dimmer than Star Y but brighter than Star X. Star V is brighter than Star Z but dimmer than Star Y. Which star is the second brightest?
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.
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?
In the question given below are two conclusions followed by five statements. You have to choose the correct set of statements that logically satisfies conclusions. Conclusions: I. Some Star are Moon II. Some Sun are not Mars Statements: I. Some Sun are Moon, Some Moon are star and No star is Mars. II. Some Sun are Moon, All Moon are Star and No Star is Mars. III. All Sun are Moon, All Moon are Star and Some Star are Mars. IV. All Sun are Moon, Some Moon are Star and No Star is Mars. V. Some Sun are Moon, Some Moon are Star and No Moon is Mars.
(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.
Read the passage carefully and choose the best answer to each question out of the four alternatives and click the button corresponding to it. In the world today we make health an end in itself. We have forgotten that health really means to enable a person to do his work and do it well. A lot of modern medicine, and this includes many patients as well as many physicians, pay very little attention to health but very much attention to those who imagine they are ill. Our great concern with health is shown by the medical columns in newspapers, the health articles in popular magazines and the popularity of television programmes and all those books on medicine. We talk about health all the time. Yet for the most part the only result is more people with imaginary illness. A healthy man should not be wasting time talking about health : he should be using health for work.
Talking about health all the time makes people
If a 400 V, 50 hz star connected, 3-phase squirrel cage induction motor is operated from 400V and 75 Hz supply. The torque that the motor can now provide while drawing rated current from the supply will _________
Which type of starter is recommended for 100 hp, 440 V, 50 Hz, 3 phase Star connected squirrel cage induction motor for agriculture water pump application?
Read the passage carefully and choose the best answer to each question out of the four alternatives and click the button corresponding to it. In the world today we make health an end in itself. We have forgotten that health really means to enable a person to do his work and do it well. A lot of modern medicine, and this includes many patients as well as many physicians, pay very little attention to health but very much attention to those who imagine they are ill. Our great concern with health is shown by the medical columns in newspapers, the health articles in popular magazines and the popularity of television programmes and all those books on medicine. We talk about health all the time. Yet for the most part the only result is more people with imaginary illness. A healthy man should not be wasting time talking about health : he should be using health for work.
Modern medicine is primarily concerned with
Read the passage carefully and choose the best answer to each question out of the four alternatives and click the button corresponding to it. In the world today we make health an end in itself. We have forgotten that health really means to enable a person to do his work and do it well. A lot of modern medicine, and this includes many patients as well as many physicians, pay very little attention to health but very much attention to those who imagine they are ill. Our great concern with health is shown by the medical columns in newspapers, the health articles in popular magazines and the popularity of television programmes and all those books on medicine. We talk about health all the time. Yet for the most part the only result is more people with imaginary illness. A healthy man should not be wasting time talking about health : he should be using health for work.
The passage suggests that