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.

1.What is the proper definition of power system stability? 2.some times a blue spark is visible in the secondary side of a distribution transformer at the contact position of bushings and fuse wire,why?

1 Answers  

---

how to decide the panel size like MDB ,SMDB PANEL SIZES

0 Answers  

---

can we start a 6.6kv ht motor with 415 lt supply

1 Answers  

---

How do you calculate of power factor, if it is lagging or leading for unit(1).

4 Answers  

---

Which device is used for the source of emission of electrons in a crt?

0 Answers  

---

---

I have a relay contact rated at 220v dc which is supplied with a 24vdc from the panel,for it to trip the dampers(24vdc).What if the application of the relay changes so that it should work at its rated 220vdc then will it work at 24vdc supply given or any other consideration needs to be taken .....

0 Answers  

---

pre arcing time of ehv breaker

0 Answers  

---

WHY KVAR IMPORTANT WHEN ANY PLANT IS RUNNING ON IT'S OWN POWER PLANT?

1 Answers  

---

ups and invertor battery selection chart and full formula

2 Answers   APC,

---

what is ASCR cable and where we use it?

6 Answers   BSL,

---

when we conduct high voltage testing why milli amp. is required?

2 Answers  

---

What is application/Function of Electro chlorinator in Offshore Oil & gas Platform ?

1 Answers  

---