Answer / partha podder

Starting current of a motor is high.The simplest way to
start a three-phase induction motor is to connect its
terminals to the line. In an induction motor, the magnitude
of the induced EMF in the rotor circuit is proportional to
the stator field and the slip speed (the difference between
synchronous and rotor speeds) of the motor, and the rotor
current depends on this EMF. When the motor is started, the
slip speed is equal to the synchronous speed, as the rotor
speed is zero (slip equal to 1), so the induced EMF in the
rotor is large. As a result, a very high current flows
through the rotor. This is similar to a transformer with the
secondary coil short circuited, which causes the primary
coil to draw a high current from the mains. When an
induction motor starts DOL, a very high current is drawn by
the stator, on the order of 5 to 9 times the full load
current. This high current can, in some motors, damage the
windings; in addition, because it causes heavy line voltage
drop, other appliances connected to the same line may be
affected by the voltage fluctuation. To avoid such effects,
several other strategies are employed for starting motors.

Answer / mahesh chaudhari

Generally its 5 to 6 times than that of rated specified
current on motor name plate.

Answer / simon

It varies 4rm motor 2 motor & supply 2 supply.

what happen when dc supply is given to the transformer

9 Answers   Bhel,

---

1.Z transform always lies around ? a) origin b) pole c) zero d) z=1. Multiples Mcqs which is bother me can’t find answers on internet. Some help required with little explanation . Note: this is not homework or related to any test. Thanks

0 Answers   CCP,

---

why we are not earthing ht cable at both the ends(sending & receiving end)?

5 Answers   Essar,

---

What is the different types of cable & current capacity of cable

0 Answers  

---

How much ampere can withstand for 2sq mm c able?

2 Answers  

---

how to find transformation ratio of squirrel cage induction motor

0 Answers   BITM, WER,

---

what is the benift of HT metering & LT metering

1 Answers  

---

what is the difference between "ampere trip and ampere frame"

1 Answers  

---

Send me Model Question paper for the post Scientific Assistant in NPCIL

0 Answers  

---

write encoder 17 pins details? pin a;b+, pin b;w+,..pin s & t. what is the meaning of b+, w+? explain;

0 Answers  

---

i want to syncronise 5 nos of DG. How? pls reply

3 Answers  

---

ell me capacitor bank chossen formula.load in KW

1 Answers  

---