Synchrounous motor is three phase motor,but its not self
starting .why?
Answer Posted / raul
when a 3-phase supply is provided to the stator winding of
the synch motor, a rotating field is produced n adjacent N-
S poles r formed on the stator windings.....due to rotor
inertia the rotor is not able to follow the rotating
magnetic field rotating at synch speed......therefore some
means has to be provided to make it self
starting........the solution lies in this
principle............the rotor is generally of squirrel
cage construction which speeds up as a induction motor and
when the motor picks up speed close to synch speed, the
rotor windings r excited by d.c. thus forming adjacent
poles on the rotor.....and in this way the stator poles
locks in with the rotor poles with opposite polarity to
rotate the rotor at synch speed...........that why synch
motor is DOUBLY EXCITED.
| Is This Answer Correct ? | 2 Yes | 2 No |
Post New Answer View All Answers
why does make gain margin and phase margin on same plot.?
1. Design a counter which counts 0, 4, 8, 2, 6, and repeats using: 1.a using JK flip flops 1.b using T flip flops 1.c using D flip flops
some time we open engine breaker 8.0 MW load but plant not trip. and another time engine open 4.0 MW load engine trip why? individually engine breaker open & individually emergency stop why difference?
Differentiate between Zero and Negative sequence current
What are reasond for high wattage in single phase induction motors
bsnl tta exam question
Give the expression for the frequency of oscillations in an op-amp sine wave oscillator?
Why the field rheostat is adjusted such that the voltmeter reads 380V
What is the formula for calculating the Instantaneous Short Circuit & overcurrent for any breaker
Is there chopping current in resistive circuit
Dear sir, my knowledge about cable size determination is limited. Though I read examples I could not calculate the Cable size required for electric driven pump 40 KW, 380 Volt, 50 HZ, 50 meter from transformer and it is three phase star delta starting. Please help as there is no one in my surroundings to help.
List examples of current sources?
what is the meaning of number in (11, 31, 61,14, etc. CDG11, CDG31, CDG61, DDT32
Why PT voltages are measured with respect to ground? What do u mean by voltage or current polarized.
what are types of encoder