Why a single-phase induction motor not an inherently
self-starting machine?
Answer Posted / 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 |
Post New Answer View All Answers
in the directional overcurrent and earthfault protection,normally we are setting the angle 45 deg lead for phase fault overcurrent and -45 deg lead for earthfault fro forward direction.but both the fault are operating on the same angle region only.why?how the relay will response?
what is data block in plc ? How the values of data block are written and read by hmi ? what is the difference between function and function block ?
Is the theorem applicable to ac sources?
11kv/433v delta/star distribution transformer primary side full load Ht current is 83.33A in , but input side VCB rating 800A.why?
what is reverse power relay brief explanation and in b/w where it is connected
What are the properties of a resistor?
list the type of vfd? wich is sutable for heating kiln?
why the electrolyte level in lead acid battery is maintained 2.5 cms above electrodes?
please send me previose rrb junior engineer qustion papers
CT Ratio of a energy meter connection is Red Phase : 100/5A, yello Phase : 50/5A & Blue phase : 100/5 A what is the overall Multiplication factor
If the earth is a good conductor of electricity, why don't people get shocked every time they walking on earth?
Cb closed condition if there is a tcs fail whether cb will trip or not
Write down the name of 2 lady Bir Pratin of Bangladesh
i have 500 amp inductive load of motors ,,,pleas tell me how can i calculate for capacitor bank for improving my power factor to 99 .....calcullations for capacitor bank,,,,
Pls tell me whether we can use EN3A material for shafts of Permanent magnet alternator.What will be the effect of magnetic and nonmagnetic material for shafts on magnetic properties of PM rotor .