Interested to Buy Any Domain ? << Click Here >> for more details...
Answer Posted / rama krishna
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.
| Is This Answer Correct ? | 4 Yes | 10 No |
Post New Answer View All Answers
what is a vector protection in transformer
why co incidence factor considered in transformer sizing?
Why the dc voltage drop during starting of emergency lube oil pump? The Voltage drop from 135kv to 125 kv for one min. before re-establish to 135kv?
what is the difference between RMS & TRUE RMS VOLTAGE
1.ZEBRA conductor(large size) 2.KUNDHA conductor( small size ) 3.panther conductor(very small ) 4.lepard conductor (very very small)
What is the fault or needs to be done when frequency in ac drives is not changing?
Whether 3 phase induction motorwith 100 hp capacity , Amp 160 for which sensitive earth fault relay , type CTUM 15 can be used?
Draw a circuit diagram in which if button is open we can use socket and bulb as a series test circit and if button is close than simple we can use socket as any load purpose.
The transmission does not have options: a)Partition noise b) Flicker noise c) resistance d) Short noise and reason
TYPE'S OF BREKAR ,WHAT IS TRANSFORMAR & SAFTY. STARTER DOL & STAR DELTA STARTER.
What is PQA???Applications........
difference between semiconductor & conductor & insulator?
How Can I calculate for the photometrics requirements for a street lighting? Data given are: 45 units of 6 meter light pole with 150 watts metal halide lamp, 220 volts and installed in a promenade area.
how to calculate kvar in Akiva
