AC motor (1 Viewer)

[Xayma]

I think you will find I corrected myself. Technically speaking though I am correct, as there is a split ring commutator and only one, not split rings (a plural) which was mentioned.

 

[DavidB]

XAYMA....you are so gay cuz, its not even funny.

I understand u like showing off and shit...but y wuld u mention a universal motor if its asking about AC motors??? U just confused the hell out of everyone unnecessarily.

Im with the ilovechildren person
(U ROCK!)

Peace

 

[Xayma]

A universal motor is also an AC motor just as much as the others. It allows variable speed without expensive control technology as opposed to a synchronous motor.

 

[CrashOveride]

Why do ac electric motors still work even though the current is constantly changing polarity?

 

[Jase]

No what you need to ask yourself is why don't DC motors work without a commutator...

 

[LSP]

Why do ac electric motors still work even though the current is constantly changing polarity?

if the magnetic field is created by coils, when the polarity changes, the direction of magnetic field also changes so that it will continue to spin

 

[CrashOveride]

though it means the rotor must rotate at the same frequency as the ac current. coz i was thinking like if u just turned it on then in the first few split seconds the polarity would already be changing and hence the forces acting on the sides would keep alternating. But i just read ac electric motors arnt self-starting

 

[Xayma]

though it means the rotor must rotate at the same frequency as the ac current. coz i was thinking like if u just turned it on then in the first few split seconds the polarity would already be changing and hence the forces acting on the sides would keep alternating. But i just read ac electric motors arnt self-starting

Syncronous run at 50 cycles per second. Universal can run at any due to the reason that all the fields switch.

 

[CrashOveride]

how do you mean all the fields switch ?

 

[Xayma]

Universal the electromagnets change polarity at the same time as the armature.

 

[senso]

are you all sure we need to know all these different ac motors?
I swear the most the syllabus asks for is to contrast dc and ac.

 

[helper]

It is one of those unclear things. They removed the comparison between the types of AC but left the prac work in for induction motors, and the comparison in of AC and DC, which it is assumed is mainly for the AC synchronous and DC but could be for the universal.

 

[tennille]

Yeah, i think you do. It does mention induction motor in the syllabus.

 

[sub]

can we get away without knowing this universal motor? ive never heard of it b4... only synchronous and the induction ac motors...

 

[helper]

More than likely yes but in an longer answer they might want the detail.

 

[sub]

k, can u explain the synchronous motor to me? apparently its not self-starting...why?

 

[helper]

Same as DC but with slip rings. The oscillating current changes polarity at the same time as the rotor passes the 90 degree rotation. The motor needs to be at the synchronous speed in order for the two changes to match. So a starter is needed to make them synchronous.

The Universal uses an electromagnet to produce the magnetic field that will always change at the same time as the rotation.

 

[smallcattle]

how come none of these are been mentioned in the Excel???

which one is the normal simple AC motor????

 

[helper]

That is the problem the board has no said.

 

[Xayma]

The simple normal AC motor is the synchronous, the one with slip rings.