Answer / yuvi

Induction motor is nothing but a transformer with a
rotating short circuited secondary coil.

Applying AC supply to the field causes rotating magnetic
field influencing the armature. This induces secondary
current which inturn creates its own magnetic field.

Now we have two magnetic fields that react to each other.
The armatures magnetic field tries to catchup with the
rotating magnetic field of the field circuit causing the
armature to rotate. How ever, when the RPM equals RPM of
magnetic field, there wont be any variation in magnetic
field with respect to the armature and hence there will be
no current flowing through the armature, resulting in zero
torque. Hence there will always be a difference in RPM of
magnetic field and RPM of armature. This difference is
called slip.

Higher the slip>> Higher difference in RPM>> Higher
variation in flux crossing armature>> Higher armature
current >> Stronger magnetic field by armature >> Greater
torque the motot has.

Answer / virendra joshi

Above ans is correct but for better understanding s = Ns-
N where is a (synchronous) speed of magnatic flux & n is
the actual spee of the motor .

also %s = Ns - n / NS

whycircuit breaker is not connected at the generator end where the capacity of the generator is more say 60MW, 100MW etc.

2 Answers   Adani, Adani Power,

---

Describe the method of Plate Earthing.

1 Answers  

---

how much current a 100 sq mm busbar will carry?

1 Answers   ABB,

---

what is (+) and (-) in generator field detector stand for?

0 Answers  

---

why two point starter,three point starter, four point starter cannot be used for A.C machines?

2 Answers  

---

Explain what is electric traction? Explain few advantages of electric traction system?

0 Answers  

---

What is meant by H.R.C fuse?

40 Answers   Gas Projects, GSCE, Taj Group,

---

what is back trip and re-trip in protection schemes? why these two? define me the exact function of these two?

1 Answers   Siemens,

---

Insulater disk using formula for 33/66/135 line h t line

1 Answers   Hofincons, Kirloskar, KPTCL,

---

when we megger is not damaged when we are measuring very low resistance? high d.c. voltage is produced in megger so according to i=V/R. current will be high so what is the reason ?

1 Answers  

---

Is there thumb rule to calculate how many Insulators to be used for Transmission line of different volatges

3 Answers   CS,

---

how we can check that any motor is faulty may be single phase or three phase?

2 Answers   MAHINDRA,

---