Ac and Dc generators question (1 Viewer)

[petermaniah198]

Describe how the structural differences between AC and DC generators are related to economic reasons for choosing AC generators over DC generators (4 marks)

Help, i don't know what to mention apart from the split ring commutators and slip ring.

 

[leehuan]

AC generator doesn't even need a commutator.

With a generator don't have to make the coils rotate. You forget that especially in three-phase generators, they make the magnetic field rotate instead.

The rotating magnetic field produced by the solenoid is something you can talk about.

 

[DatAtarLyfe]

You can also talk about the fact that in DC, the split in the split ring causes the brushes to wear and tear (as the sharp edges continually strike the brushes). However in AC, the smooth surface of the slip ring means that there is less wearing and thus less maintenance is needed, hence less costs

 

[Nailgun]

points to talk about

* less wear and tear on ac generators due to slip ring commutators, makes the ac generator cheaper in the long term due to lower maintenance costs as compared to the dc motors higher maintenance split ring commutator

*also becuase of the nature of ac generator and the coil reversing polarity every half turn and the fact you can step up the voltage and reduce power loss (P = I^2 x R and P = VI ) its much cheaper to transmit over long distances and efficient, while also allowing economies of scale to form

im pretty sure thats all you'd need to talk about, but make sure to both say why ac is good, and in contrast why dc is bad for each point (making up the four marks) and also explicity refer to the structure of the generator i.e. the constant friction with the brushes and commutator during the rotation of the coil results in much greater wear and tear in the DC motor as compared to the ac motor where there is much less contact between the coil and the commutator

 

[Nailgun]

AC generator doesn't even need a commutator.

With a generator don't have to make the coils rotate. You forget that especially in three-phase generators, they make the magnetic field rotate instead.

The rotating magnetic field produced by the solenoid is something you can talk about.

what does this have to do with economic reasons lol

 

[leehuan]

points to talk about

* less wear and tear on ac generators due to slip ring commutators, makes the ac generator cheaper in the long term due to lower maintenance costs as compared to the dc motors higher maintenance split ring commutator

*also becuase of the nature of ac generator and the coil reversing polarity every half turn and the fact you can step up the voltage and reduce power loss (P = I^2 x R and P = VI ) its much cheaper to transmit over long distances and efficient, while also allowing economies of scale to form

im pretty sure thats all you'd need to talk about, but make sure to both say why ac is good, and in contrast why dc is bad for each point (making up the four marks) and also explicity refer to the structure of the generator i.e. the constant friction with the brushes and commutator during the rotation of the coil results in much greater wear and tear in the DC motor as compared to the ac motor where there is much less contact between the coil and the commutator

Except that's more for a power transmission lol, cause it goes back to transformers.

But true

 

[Nailgun]

Except that's more for a power transmission lol, cause it goes back to transformers.

But true

yeah but i think power transmission is the big comparison they're trying to make in the syllabus economically so even if the question isn't completely worded to imply that, its probably what they're looking for lol

at any rate, i couldnt think of anything else off the top of my head lele

 

[leehuan]

what does this have to do with economic reasons lol

You don't need a commutator

 

[WrittenLoveLetters]

When do we learn this and should I be scared that I don't know this

 

[Nailgun]

You don't need a commutator

Ah I see what you mean now
and you still need a slip ring commutator for standard ac though? you can't just attach the coil to the brushes lol

and AC induction motors are way more complex than the standard kind so I would assume they are more expensive in general lol

but i see your point

 

[Nailgun]

When do we learn this and should I be scared that I don't know this

nah you're good

i think this is like section 3 or 4 material
the ac induction stuff is section 5

(there are 5 sections)

 

[WrittenLoveLetters]

I only just started induction GG

 

[Nailgun]

I only just started induction GG

yeah dw lol im just hardcore

 

[leehuan]

Ah I see what you mean now
and you still need a slip ring commutator for standard ac though? you can't just attach the coil to the brushes lol

and AC induction motors are way more complex than the standard kind so I would assume they are more expensive in general lol

but i see your point

I didn't exactly mean an induction motor with the squirrel cage

Of course, at the industrial level their three phase generators are quite something. But even at the commercial level pretty sure we use generators with the rotating magnetic field over commutator present ones.

 

[Nailgun]

I didn't exactly mean an induction motor with the squirrel cage

Of course, at the industrial level their three phase generators are quite something. But even at the commercial level pretty sure we use generators with the rotating magnetic field over commutator present ones.

Ah I googled it an now I know what you mean lelele
That's a pretty smart design actually lel, the net result is kind of like a combo of dc and ac

 

[anomalousdecay]

Describe how the structural differences between AC and DC generators are related to economic reasons for choosing AC generators over DC generators (4 marks)

Help, i don't know what to mention apart from the split ring commutators and slip ring.

Economic reasons for AC:

- More efficient over long distances
- Less power stations are required as a result
- AC power is more readily manipulated by transformers and rectifiers.

You can use those points and base it off how the main structural differences allow AC satisfy these requirements whereas DC can't satify these requirements.

 

[RobbParnes]

AC generator doesn't even need a commutator.With a generator don't have to make the coils rotate. You forget that especially in three-phase generators, they make the magnetic field rotate instead.
The rotating magnetic field produced by the solenoid.

www.7pcb.com

 

[leehuan]

AC generator doesn't even need a commutator.With a generator don't have to make the coils rotate. You forget that especially in three-phase generators, they make the magnetic field rotate instead.
The rotating magnetic field produced by the solenoid.

Thread's a bit old and I mentioned this already.