Why a single-phase induction motor not an inherently self-starting machine?

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Why a single-phase induction motor not an inherently
self-starting machine?

Question Posted / ramesh

11 Answers
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Why a single-phase induction motor not an inherently self-starting machine?..

Answer / balamurugan

The 3-phase induction motor have the rotating magnetic field
(R.M.F),whereas the single phase induction motor does not
produce R.M.F,...According to the dobule field revolving
theory that the thing is explained....

Is This Answer Correct ?

42 Yes

12 No

Why a single-phase induction motor not an inherently self-starting machine?..

Answer / srini

In 1 phase induction motor has be produce alternating
flux. it does not be produce rotating flux.
so zero torque will be produce. hence add some methods
like phase splitting method, we split the winding in
starting or running winding can be get the 2 phase winding
so, this method can be make induction motor is to be self
start.

Is This Answer Correct ?

16 Yes

6 No

Why a single-phase induction motor not an inherently self-starting machine?..

Answer / jaimin modi

in 1 phase i.m the stator is distributed wdg. & squirrel
cage rotor.When it is fed from 1 phase supply the sator
wdg. produces flux which is alternating i.e. alternates
along one space axis only.it is not synchronously revolving
flux as in case of 2 or 3 phase wdg.fed from 2 or 3 phase
supply.this pulsating flux acting on stationary squirrel
cage rotor can not produce rotation(remember:only revolving
flux can)so....it made self start by means of capacitor
with 90 phase split.ok.bye

Is This Answer Correct ?

13 Yes

8 No

Why a single-phase induction motor not an inherently self-starting machine?..

Answer / sambhu chandran

because in 1 phase induction motor the flux produced is
alternating. so the net torque is zero ,for making it as uni
directinal we use several methods like phase splitting
method,capacitor start capacitor running,etc

Is This Answer Correct ?

7 Yes

6 No

Why a single-phase induction motor not an inherently self-starting machine?..

Answer / nisha meena

1. Yes 2. Yes 3. Yes 4. No 5. No 6. No 7. No 8. Yes 9. Yes 10. No

Is This Answer Correct ?

0 Yes

1 No

Why a single-phase induction motor not an inherently self-starting machine?..

Answer / gunasekaran

net torque is zero for single phase motor because average
value of the single phase circuit is zero

Is This Answer Correct ?

12 Yes

14 No

Why a single-phase induction motor not an inherently self-starting machine?..

Answer / raghav mishra

Single phase motor needs different method to start and run. The single phase line itself will not produce rotating field in stator because of only one sinusoidal not three like three phase supply. To create the rotating field, we must split the phase into two different sinusoidal wave that lagged for some degree each other. There are two method that commonly in used;
1. Use smaller diameter of winding wire in starting winding, so the current will flow faster compare to Running Winding.
2. Use of capacitor in starting winding- capacitor fast charge and discharge action makes the current leading.

When the supply is applied, the current in starting winding will lead the current in running winding hence we have rotating field that will induced emf in rotor. So the push pull action will began immediately.The Rotor turns and started.

Is This Answer Correct ?

1 Yes

4 No

Why a single-phase induction motor not an inherently self-starting machine?..

Answer / krishna

because single phase supply is
pulsations in nature it can't able to
produce rotating magnetic field and
there is chance for magnetic locking.
for above reason motor can't able to
run

Is This Answer Correct ?

0 Yes

3 No

Why a single-phase induction motor not an inherently self-starting machine?..

Answer / meghraj prasad

becoZ wen the main winding is exicted
frm a 1Ð¤ supply,it produces
alternatin magnetic field instead of
RMF..nd acording to the field
revolving theory we know that any
alternating vector can be resolved in
two vectors rotating in opposite
direction and each having magnitude
equal to half of original vector..and
the vector will be rotate in such a
way that resultant will be zero so it
fails to produce net starting torque
and hence it is not self starting.,bt
i cn b made self starting...

Is This Answer Correct ?

0 Yes

3 No

Why a single-phase induction motor not an inherently self-starting machine?..

Answer / pranu

some one say about magnetic locking... the actual answer...

Is This Answer Correct ?

2 Yes

6 No