Interested to Buy Any Domain ? << Click Here >> for more details...
without any excitation we can strt any dc or ac moter?
- 6 Answers
- 12822 Views
- Bhel, I also Faced
- E-Mail Answers
Answer Posted / guest
The answer to this question depends upon the type of
motor.The excitation means supply needed to establish the
working flux.
AC motors
3 phase Synchronous Motor
Cannot be started without excitation.Because the magnetic
locking(which is necessry for continous rotation) between
rotating stator field(created due to balanced 3 phase
supply to stator) and rotating rotor field(rotor is being
rotated intially by external means) is not possible without
excitating the field.
3 phase Induction Motor
There is no concept of excitation in this motor.Motor runs
on the principle of induction,So only 3 phase stator
current and rotror bars shorted at end is needed.There is
no need of excitation on rotor bars.
1 phase Induction Motor
There is no concept of excitation in this motor.Only supply
is needed to Stator winding(don't confuse this with
excitation.This is different from excitation).So motor will
run with supply connected to stator.However the stator
winding is splitted into two parts for providing phase angle
(which is necessary for rotation) bewween current flowing
through main and auxiliary windings.
DC motors
AC supply is given to stator winding which is converted
into DC by means of commutator.Field winding, which is
connected in series in case of series motor,
in parallel in case of shunt motor or
in combination in case of compound motor.
In all the three cases excitation is needed to run the
motor.
conclusions:
1)some AC motors(Induction motors: 3 phase and 1 phase) can
started without field where as some AC motor(3 phase
synchronous motor) cann't be started without field.
2)DC motors cann't be started without excitation.
Author:arbelectbit@yahoo.com
| Is This Answer Correct ? | 25 Yes | 1 No |
Post New Answer View All Answers
what is the difference between single ratio, multiple core and multiple ratio, multiple core ? please explain.
what is the transmission loss for electrical supply? specifically a large shopping complex where the grid is half KM away, what will the % of transmission loss? is there any transmission loss for captive unit generation for above set? thanks
in cvt,there are two windings,1a,1n and 2a,2n.in my one project i use only one winding i.e.1a,1n. the other winding is not in use, so i connect it in open delta and want to close it by ibsertibg thermal resistor. the output of cvt is 132kv/115/sqrt3. plesae tell me exact value of resistor, so i may close it to avoid the resonance phenomenin. send me answer on this email adress please. aetcon-po@aetcon.com
What are test signals and their significance?
A 3-PHASE TRANSFORMER IS USED TO STEP-DOWN THE VOLTAGE OF A 3-PHASE, 11KV FEEDER LINE. PER-PHASE TURNS RATIO IS 12.FOR A PRIMARY LINE CURRENT OF 20A, CALCULATE THE SECOUNDRY LINE VOLTAGE, LINE CURRENT AND OUTPUT KVA FOR FOLLOWING.A)STAR- DELTA.B)DELTA-DELTA.
What will be the size of copper cable (each for 3 phase and 1 neutral) from Service connection Kit-Kat to Panel Board (i.e. to main switch) for a 6 pole 3-phase AC induction motor of 200 H.P. capacity? Amp-255 A, Frequency:- 1450 rpm.
What is depreciation factor?
What is the basic rule for block diagram reduction technique?
what are problems caused by the pdu in rack server
which network topology offers the greatest level of tolerance?
comparision between ACB and VCB
What is difference between Harmonic and Non harmonic Capacitor Bank?
How do i carry out or know the vector group of a Dyn1 and Dyn5 transformer
how to compare with Relay settings for HT< panels, RMU panel, and PSS CSS transformer?? 1) Load amps, 2)Tripping time, 3) CT ratio, 4)Cable size 5) Transformer KVA rating 6) transformer full load amps
why the rotor current becomes in steady state during high slip region? please verify with equations.
