menu search
person
speed control methods of three phase induction motor?
thumb_up_alt 0 like thumb_down_alt 0 dislike
140 views

Your answer

Can you give answer to this question ?

Upload an image:

Privacy: Your email address will only be used for sending these notifications.

2 Answers

Speed control of three phase induction motor

•There are two types of AC motor one is synchronous motor and second is asynchronous motor (induction motor).

•Three phase induction motor is a self starting motor.

•Motor have two main parts one is stator and second is rotor.

•Speed of three phase induction motor can be control from stator side and rotor side.

•The main method for controlling speed of induction motor are one is by changing number of poles second is by stator voltage control third is by V/F control and fourth is by rotor resistance control.

By changing number of poles :

•This method is use for squirrel cage rotor motor only.

image

•The number of stator poles can be change by three methods one is multiple stator winding and second is method of consequent poles and third is pole amplitude modulation.

•We have,"    N_s =  120f/P

•Where, N_s  is the synchronous speed , f is the frequency , P is the number of poles.

•So by changing the number of poles synchronous speed changes.

By stator voltage control :

•We have, 

image

•Torque is directly proportional to stator voltage.

•This method is very easy and cheap but still use rarely.

•Because by decreasing the voltage torque will reduce.

•But this will increase current in motor which will heat the motor which is not good it causes losses.

•Also the torque is proportional to square of voltage so large voltage change is required for changing torque.

By V/F control :

•We have,  N_s=  120f/P

•Where, N_s  is the synchronous speed , f is the frequency , P is the number of poles.

•Also, V=4.44φfTK  ( which means φ α V/f ).

•Where, V is the voltage , φ is the flux , f is the frequency , T is number of turns per phase , K is the winding constant.

•If we increase the frequency (f) flux (φ) will decrease because they are inversely proportional and if we increase the voltage (V ) flux (φ) will increase because they are directly proportional.

•In this method we have to keep V/f ratio constant.

By Rotor resistance control :

•We have, Torque α slip/(rotor resistance)

•This method is use for wound rotor motor only.

image

•By adding external variable resistance to rotor via slip ring we can control the speed of motor.

•It can also use as starter.

•It is simple method.

•But there is resistance means heat means losses means less efficiency.

thumb_up_alt 0 like thumb_down_alt 0 dislike

Speed control of three phase induction motor

image

image

image

image

image

image

thumb_up_alt 0 like thumb_down_alt 0 dislike
← Prev Question Next Question →
Request Answer

Related questions

thumb_up_alt 0 like thumb_down_alt 0 dislike
86 views 1 answer
thumb_up_alt 3 like thumb_down_alt 0 dislike
134 views 2 answers
thumb_up_alt 0 like thumb_down_alt 0 dislike
61 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
58 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
120 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
63 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
81 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
115 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
49 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
187 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
87 views 2 answers
thumb_up_alt 1 like thumb_down_alt 0 dislike
76 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
104 views 2 answers
thumb_up_alt 0 like thumb_down_alt 0 dislike
68 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
65 views 0 answers
thumb_up_alt 0 like thumb_down_alt 0 dislike
38 views 0 answers
thumb_up_alt 0 like thumb_down_alt 0 dislike
160 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
77 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
85 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
422 views 1 answer
thumb_up_alt 1 like thumb_down_alt 0 dislike
94 views 2 answers
thumb_up_alt 0 like thumb_down_alt 0 dislike
87 views 2 answers
thumb_up_alt 0 like thumb_down_alt 0 dislike
64 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
87 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
71 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
198 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
100 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
78 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
77 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
62 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
79 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
88 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
104 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
37 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
51 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
134 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
45 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
54 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
2,721 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
77 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
65 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
34 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
107 views 2 answers
thumb_up_alt 0 like thumb_down_alt 0 dislike
78 views 2 answers
thumb_up_alt 0 like thumb_down_alt 0 dislike
134 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
52 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
73 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
82 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
53 views 1 answer
thumb_up_alt 0 like thumb_down_alt 0 dislike
57 views 1 answer
Welcome to AskOrAnswerMe.com , where you can ask questions and receive answers from other user. Feel free to ask any question. Help everyone by giving best answer to the questions.

11,555 questions

10,173 answers

190 comments

4,088 users

...