Answer / romesh roy nigam

Cogging - The rotar of squirral cage motar some times
refuse to start at all,particularly when the voltage is low
this when number of rotar teeth becomes equal to numbers of
stator teeth & due to magnatic locking between stator and
rotar teeth.
Crawling - The phenomenon when squirral cage motar some
times showing tendency to run stably at speed as low as one
seventh of its synchronus speed

Answer / raul

COGGING : when the stator and rotor poles of a 3-phase
Induction motor r either equal or have an integral
ratio......there is a strong alignment or magnetic locking
b/w the stator n rotor teeths.......so due to this the
motor is unable to start inspite of applying full rated
voltage across the motor........
CRAWLING : it is inability of a 3-phase induction motor to
speed up to desired slip speed and has a tendency to run at
a stable speed of 1/7th of the synchronous speed. this
normally occurs due to the 7th harmonic present in the non-
sinusoidal flux wave.......it can be avoided by using short
chorded windings.......

What is the function of wave trap in an electrical substation?

2 Answers  

---

what is the meaning of DSL

4 Answers   Airtel,

---

Draw a Block diagram of TWO UPS systems connected in Parallel in Paralled mode?

0 Answers   HSL,

---

What is the operating principle of turbo-generator.

0 Answers  

---

Make a list of materials and layout diagram for a 35hp motor, to be wired at 35meter away from the MDB in a chemical factory.

2 Answers   FEWA,

---

What are IP protections used for electrical panels, JB, equipments installed in explosive zones like Petrochemicals, Oil & gas

1 Answers  

---

Can the same motor be operated in both direction ?

12 Answers  

---

what is cogging and crawling

20 Answers   ABB, Ashok Leyland, Bharat Bijlee, BMRCL, MN Dastur, Siemens,

---

The control system is used for?

3 Answers   CCP, NTPC,

---

How to Calculate The sag of OPGW in Transmission Line???

0 Answers   Zenco Systems,

---

why battery dc voltage become Half when we check with respect to ground for example 120volts + and - terminals and when we check + terminal with Earth thats 60volts why 60volts we can not ground the battery.

6 Answers   GE,

---

Explain few advantages of electric traction system?

0 Answers  

---